Asphaltene solvation and despersion process

Abstract

The capacity of a crude oil to solvate and / or disperse asphaltenes is increased by providing a crude oil which includes an additive comprising (i) a poly(butylenyl)bezene sulphonic acid; or, (ii) a poly(propylenyl)benzene sulphonic acid; or, (iii) a combination of a poly(butylenyl)bezene sulphonic acid and a poly(propylenyl)benzene sulphonic acid

Description

FIELD OF THE INVENTIONThis invention relates to increasing the capacity of a crude oil to solvate and / or disperseasphaltenes in the crude oil. In particular, although not exclusively, the invention relates toenhancing the solubility and / or dispersibility of asphaltenes in a crude oil, especially a crudeoil which has an asphaltene content.More specifically, the invention relates to a method for increasing the capacity of a crude oilto solvate and / or disperse asphaltenes in the crude oil and / or a method for enhancing thesolubility and / or dispersibility of asphaltenes in a crude oil, by adding one or more 4-poly(alkylenyl)benzene sulphonic acid derivative(s) as additive(s) to the crude oil. Further, theinvention relates to the use of one or more 4-poly(alkylenyl)benzene sulphonic acidderivative(s) as additive(s) in a crude oil, especially a crude oil which has an asphaltene content,to increase the capacity of a crude oil to solvate and / or disperse asphaltenes in the crude oiland / or to enhance the solubility and / or dispersibility of asphaltenes in a crude oil, particularlysuch use, during extraction of a crude oil from a subterranean crude oil reservoir and / or duringtransportation of a crude oil to a petroleum refinery and / or during storage of a crude oil and / orduring a blending operation of a crude oil with a different type of crude oil.BACKGROUND OF THE INVENTIONA crude oil typically includes asphaltenes. Asphaltenes include molecules having a largenumber of different and complex structures. Typically, asphaltenes comprise high molecularweight aromatic molecules, such as unsaturated macromolecules primarily of carbon andhydrogen but also containing minor components such as sulfur, oxygen, nitrogen and / or variousmetals, particularly heavy metals. Asphaltenes are characterized in terms of their solubility inaromatic solvents, and they are more commonly defined as that portion of a crude oil, which issoluble in xylene and toluene, but insoluble in paraffinic solvents, such as heptane or pentane.Asphaltenes typically exist in crude oil as soluble species and / or in the form of a colloidaldispersion, through interactions with resins present in the crude oil (e.g. asphaltenes are solvatedby interactions with the resins in a crude oil). Suitably, the solvation and / or dispersion of PF2019M006 / FF2asphaltenes in a crude oil is delicately balanced and this balance, and the capacity of a crude oilto solvate and / or disperse asphaltenes therein, may be disturbed upon pressure changes,compositional changes (e.g. by blending two or more different crude oils together or blending acrude oil with a hydrocarbon fluid), or other mechanical or physical processing operations of acrude oil.Crude oil from different geographical locations typically has its own unique physical properties(e.g. viscosity and volatility) and chemical composition (e.g. asphaltene content, sulfur content).Crude oil ranges in density and consistency, from relatively thin, light weight fluid oils toextremely thick, semi-solid heavy weight oils. Lower quality crude oils typically include a higherquantity of asphaltenes, and / or sulfur, compared with higher quality crude oils. Accordingly, itmay be necessary to blend two or more different types of crude oil together to provide a crudeoil blend having the desirable viscosity, volatility and chemical compositional characteristics tofacilitate transport and / or storage of the crude oil. For example, it may be desirable to blend alower quality heavy crude oil having a high viscosity and high asphaltene content with a higherquality light crude oil having a lower viscosity and lower asphaltene content and / or with ahydrocarbon oil, to facilitate ease of handling, transportation (e.g. by pipeline, tanker or ship)and / or storage of the lower quality heavy crude oil between the wellbore reservoir region and apetroleum refinery. However, it is recognised that mixing two different types of crude oil togethermay form a crude oil blend having a significantly lower capacity for solvating and / or dispersingasphaltenes. This diminished capacity for solvating and / or dispersing asphaltenes has been foundto occur in such blends of crude oil, even when no asphaltene insolvency exists in either of thedifferent types of crude oil alone constituting the blend.Crude oil is extracted from a subterranean crude oil reservoir by forming a well. The extractionof crude oil from the reservoir may be facilitated by natural processes (e.g. underground pressureforcing the crude oil to the surface) and / or using secondary recovery processes and / or usingenhanced recovery processes. Secondary recovery processes include injecting fluids (e.g. water,natural gas, air) into the reservoir to increase reservoir pressure; enhanced recovery processesinclude reducing the viscosity of the oil in the reservoir, for example, by injecting steam,surfactants and carbon dioxide into the reservoir. Suitably, crude oil during the extractionoperation(s) is typically subjected to a number of different physiochemical processes which mayPF2019M006 / FF3diminish the capacity of the crude oil to solvate and / or disperse asphaltenes contained thereinand / or reduce the solubility and / or dispersibility of asphaltenes in the crude oil.The diminished capacity of a crude oil to solvate and / or disperse asphaltenes, and / or a reductionin the solubility and / or dispersibility of asphaltenes in a crude oil upon pressure changes,compositional changes, or other mechanical or physiochemical processing operations of a crudeoil, presents a number of problems for: crude oil producers(commonly referred to as the upstreamsector in the oil and gas industry); in the transportation of crude oils from the wellbore region toa petroleum refinery (e.g. by pipeline, rail, ship, oil tanker); in the storage of crude oils beforethe oil is refined at a petroleum refinery (e.g. storage at the wellbore region, storage atintermediate sectors between the wellbore region and a petroleum refinery, and storage at apetroleum refinery); and, in the processing of a crude oil before it is refined at a petroleumrefinery (e.g. blending a crude oil with a different type of crude oil to form a crude oil blend).For example, the diminished capacity of a crude oil to solvate or disperse asphaltenes, and / or areduction in the solubility and / or dispersibility of asphaltenes in a crude oil, may promote theformation of asphaltene deposits that may plug and / or restrict oil flow in downhole tubulars,wellbores, choke off pipes, safety shut off valves, separator equipment, flow lines (e.g. pipelines),blending equipment, storage vessels and associated process transport mechanisms. To overcomethese disadvantages, the equipment is ordinarily taken offline and cleaned mechanically orchemically cleaned, resulting in lost production time and increased operating costs.Accordingly, there is a need to increase the capacity of a crude oil, and of a crude oil blendcomprising two or more different types of crude oil, to solvate and / or disperse asphaltenes in thecrude oil and / or crude oil blend, wherein such capacity may be lowered upon pressure changes,compositional or other mechanical or physical processing operations of a crude oil and crude oilblend; especially in respect of a crude oil or crude oil blend which has an asphaltene content.Further, there is a need to increase the solubility and / or dispersibility of asphaltenes in a crudeoil, and in a crude oil blend comprising two or more different types of crude oil, wherein thesolubility and dispersibility of asphaltenes in said crude oil and crude oil blend may be loweredupon pressure changes, compositional or other mechanical or physical processing operations ofcrude oil and crude oil blend; especially in respect of a crude oil or crude oil blend which has anasphaltene content. This will typically improve the overall efficiency and decrease operating PF2019M006 / FF4costs for extracting, transporting, storing and / or processing of crude oil before it is refined in apetroleum refinery operation at a petroleum refinery.SUMMARY OF INVENTIONThe invention provides improvements for increasing the capacity of a crude oil to solvateand / or disperse asphaltenes in said crude oil. Further, the invention provides improvements forincreasing the solubility and / or dispersibility of asphaltenes in a crude oil. Further, theinvention provides such improvements in respect of a crude oil blend comprising two or moredifferent types of crude oil. Suitably, the crude oil or said crude oil blend has an asphaltenecontent. Still further, the invention provides such improvements in respect of a refineablepetroleum feedstock which includes a crude oil or said crude oil blend.Thus, in a first aspect, the invention provides a method for enhancing the capacity of a crudeoil to solvate and / or disperse asphaltenes in said crude oil, the method comprising adding aneffective minor amount of Additive A or Additive B, or an effective minor amount of acombination of Additive A and Additive B, to the crude oil; wherein:(i) Additive A comprises one or more 4-poly(butylenyl)benzene sulphonic acid(s), whereinthe poly(butylenyl) substituent group of greater than 50 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the total mass of allsaid one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equalto 32 total carbon atoms in said substituent group, as determined by GC; and,(ii) Additive B comprises one or more 4-poly(propylenyl)benzene sulphonic acids, whereinthe poly(propylenyl) substituent group of greater than 50 mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the total mass of allsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equalto 21 total carbon atoms in said substituent group, as determined by GC.Thus, in a second aspect, the invention provides a method for increasing the solubility and / ordispersibility of asphaltenes in a crude oil, the method comprising adding an effective minoramount of Additive A or Additive B, or an effective minor amount of a combination of AdditiveA and Additive B, to the crude oil; wherein:PF2019M006 / FF5(i) Additive A, when present, is present in an effective minor amount of from 1 to 1000 ppmby mass, based on the total mass of the crude oil, and Additive A comprises one or more4-poly(butylenyl)benzene sulphonic acid(s), wherein the poly(butylenyl) substituentgroup of greater than 50 mass % of said one or more 4-poly(butylenyl)benzene sulphonicacid(s) of Additive A, based on the total mass of all said one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equal to 32 total carbonatoms in said substituent group, as determined by GC; and,(ii) Additive B, when present, is present in an effective minor amount of from 1 to 1000 ppmby mass, based on the total mass of the crude oil, and Additive B comprises one or more4-poly(propylenyl)benzene sulphonic acids, wherein the poly(propylenyl) substituentgroup of greater than 50 mass % of said one or more 4-poly(propylenyl)benzenesulphonic acid(s) of Additive B, based on the total mass of all said one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equal to 21 total carbonatoms in said substituent group, as determined by GC.In a third aspect, the invention provides the use, of an effective minor amount of Additive A orAdditive B, or an effective minor amount of a combination of Additive A and Additive B, asan additive, or a combination of additives A and B, in a crude oil to enhance the capacity of acrude oil to solvate and / or disperse asphaltenes in said crude oil, wherein: Additive Acomprises one or more 4-poly(butylenyl)benzene sulphonic acid(s), wherein the poly(butylenyl)substituent group of greater than 50 mass % of said one or more 4-poly(butylenyl)benzenesulphonic acid(s) of Additive A, based on the total mass of all said one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equal to 32 total carbon atoms insaid substituent group, as determined by GC; and, Additive B comprises one or more 4-poly(propylenyl)benzene sulphonic acids, wherein the poly(propylenyl) substituent group ofgreater than 50 mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) ofAdditive B, based on the total mass of all said one or more 4-poly(propylenyl)benzenesulphonic acid(s), has greater than or equal to 21 total carbon atoms in said substituent group,as determined by GC.In a fourth aspect, the invention provides the use, of an effective minor amount of Additive Aor Additive B, or an effective minor amount of a combination of Additive A and Additive B,as an additive, or a combination of additives A and B, in a crude oil to enhance the solubility PF2019M006 / FF6and / or dispersibility of asphaltenes in said crude oil, wherein: Additive A comprises one ormore 4-poly(butylenyl)benzene sulphonic acid(s), wherein the poly(butylenyl) substituentgroup of greater than 50 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s)of Additive A, based on the total mass of all said one or more 4-poly(butylenyl)benzenesulphonic acid(s), has greater than or equal to 32 total carbon atoms in said substituent group,as determined by GC; and, Additive B comprises one or more 4-poly(propylenyl)benzenesulphonic acids, wherein the poly(propylenyl) substituent group of greater than 50 mass % ofsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the totalmass of all said one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than orequal to 21 total carbon atoms in said substituent group, as determined by GC.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil comprises a crude oil having an asphaltene content.Suitably, in the method of the first aspect and / or use of the third aspect, the capacity of a crudeoil to solvate and / or disperse asphaltenes is enhanced upon pressure changes, compositional orother mechanical or physical processing operations of the crude oil.Suitably, in the method of the second aspect and / or use of the fourth aspect, the solubilityand / or dispersibility of asphaltenes in a crude oil is enhanced upon pressure changes,compositional or other mechanical or physical processing operations of the crude oil.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,Additive A, when present, is present in an amount of from 1 to 10000, preferably 1 to 5000,more preferably 1 to 1000, even more preferably 1 to 500, even more preferably 1 to 100, evenmore preferably 1 to less than 100, ppm by mass, based on the total mass of the crude oil.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,Additive B, when present, is present in an amount of from 1 to 10000, preferably 1 to 5000,more preferably 1 to 1000, even more preferably 1 to 500, even more preferably 1 to 100, evenmore preferably 1 to less than 100, ppm by mass, based on the total mass of the crude oil.PF2019M006 / FF7Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,when a combination of Additive A and Additive B is used, the combined treat rate of AdditiveA and Additive B is from 2 to 10000, preferably 2 to 5000, more preferably 2 to 1000, morepreferably 2 to 200, even more preferably 2 to less than 100, ppm by mass, based on the totalmass of the crude oil.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil comprises a single type of crude oil or a crude oil blend comprising two or moredifferent types of crude oil. The single type of crude oil or crude oil blend may further includea hydrocarbon oil (i.e. not a crude oil).Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil comprises a single type of crude oil having an asphaltene content or a crude oilblend comprising two or more different types of crude oil, wherein at least one, preferably eachof said different type of, crude oil has an asphaltene content.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil represents, or forms part of, a refineable petroleum feedstock which may berefined in a petroleum refinery operation at a petroleum refinery.Suitably, the crude oil comprises intermediate (light) crude oils, medium crude oils, heavycrude oils and shale oils, and combinations thereof.Unexpectedly, it has been found that a significant increase in the capacity of a crude oil tosolvate and / or disperse asphaltenes therein may be achieved by employing the particular 4-poly(butylenyl)benzene sulphonic acid(s) (Additive A) or the particular 4-poly(propylenyl)benzene sulphonic acid(s) (Additive B) as an additive in the crude oil, whena major amount of the poly(butylenyl) substituent groups of Additive A or a major amount ofthe poly(propylenyl) substituent groups of Additive B have the defined narrow total carbonchain length distribution, wherein such capacity of the crude oil may otherwise be loweredupon pressure changes, compositional or other mechanical or physical processing operations ofthe crude oil (e.g. forming a crude oil blend). Further, it has been found that a significant increasein the solubility and / or dispersibility of asphaltenes in a crude oil may be achieved by PF2019M006 / FF8employing the particular 4-poly(butylenyl)benzene sulphonic acid(s) (Additive A) or theparticular 4-poly(propylenyl)benzene sulphonic acid(s) (Additive B) as an additive in the crudeoil, when a major amount of the poly(butylenyl) substituent groups of Additive A or a majoramount of the poly(propylenyl) substituent groups of Additive B have the defined narrow totalcarbon chain length distribution, wherein the solubility and / or dispersibility of asphaltenes mayotherwise be lowered in the crude oil upon pressure changes, compositional or other mechanicalor physical processing operations of the crude oil (e.g. forming a crude oil blend). Still further,this technical effect is achievable by adding a relatively small amount (e.g. 1 to 1000, preferably1 to less than 100, ppm by mass) of Additive A or Additive B to a crude oil. Suitably, the useof a relatively small amount (e.g. 1 to 1000, preferably 1 to less than 100, ppm by mass) of theparticular 4-poly(butylenyl)benzene sulphonic acid(s) (Additive A) or the particular 4-poly(propylenyl)benzene sulphonic acid(s) (Additive B) , in a crude oil typically significantlyincreases the capacity of crude oil to solvate and / or disperse asphaltenes therein, and / or asignificantly increases the solubility and / or dispersibility of asphaltenes in a crude oil,compared with the crude oil not including either Additive A or Additive B.The increased capacity of a crude oil to solvate and / or disperse asphaltenes therein, and / or theincreased solubility and / or dispersibility of asphaltenes in a crude oil, may permit (i) increasedamounts of asphaltenes to be solvated and / or dispersed in a crude oil; and / or, (ii) formationof a crude oil, or formation of a crude oil blend, having a defined asphaltene contentwherein the asphaltenes are more stably solvated and / or dispersed therein (i.e. asphalteneprecipitation from and / or agglomeration in the crude oil is reduced).Still further, it has unexpectedly been found, the use of Additive A is much more effective thanAdditive B. Suitably, in the method of the first and second aspects and / or use of the third andfourth aspects, an effective minor amount of Additive A is added to a crude oil.Although Additive A has been found to be more effective than Additive B, a combination ofAdditive A and Additive B, typically provides an effect which is at least comparable to the useof Additive A alone. Suitably, in the method of the first and second aspects and / or use of thethird and fourth aspects, an effective minor amount of a combination of Additive A andAdditive B is added to a crude oil.PF2019M006 / FF9Suitably, in in the method of the first and second aspects and / or use of the third and fourthaspects, Additive A or Additive B, or a combination of Additive A and Additive B, is eachindependently added to the crude oil before the crude oil is at a petroleum refinery or when thecrude oil is at a petroleum refinery. Preferably, Additive A or Additive B, or a combination ofAdditive A and Additive B, is each independently added to the crude oil before the crude oil isat a petroleum refinery.For the avoidance of doubt, when Additive A or Additive B, or a combination of Additive Aand Additive B, is each independently added to a crude oil we mean that each additive or thecombination of additives may be independently added directly to a crude oil(s) as definedherein, each additive or the combination of additives may be independently added to a crudeoil blend as defined herein, and / or each additive or the combination of additives may beindependently added to a refineable petroleum feedstock comprising a crude oil or crude oilblend as defined herein.Suitably, Additive A or Additive B, or a combination of Additive A and Additive B, is eachindependently added to a crude oil at one or more crude oil production and / or processing stagesbefore the crude oil arrives at a petroleum refinery. Suitably, Additive A or Additive B, or acombination of Additive A and Additive B, is each independently added to a crude oil at oneor more crude oil production and / or processing stages before the crude oil arrives at a petroleumrefinery selected from: (i) to a crude oil residing in a subterranean crude oil reservoir, forexample, during the extraction process by injecting the additive(s) into the crude oil reservoirvia the wellbore; (ii) to a crude oil during the storage of the crude oil, for example, to a crudeoil being stored in storage tanks, which tanks may be located at the wellbore region, or atintermediate locations between the wellbore region and petroleum refinery; (iii) to a crude oilduring the transportation of a crude oil, for example, to a crude oil being transported by pipeline,ship, rail, oil tanker, especially to a crude oil being transported from the wellbore region to apetroleum refinery; (iv) to a crude oil before or during the processing of a crude oil before itarrives at a petroleum refinery, for example, to a crude oil being blended with a different typeof crude oil, and / or hydrocarbon fluid, to form a crude oil blend. Preferably, Additive A orAdditive B, or a combination of Additive A and Additive B, is each independently added tothe crude oil at one or more crude oil production process stages selected from: (i) to a crude oilduring the storage of a crude oil; (ii) to a crude oil during the transportation of a crude oil, PF2019M006 / FF10especially to a crude oil being transported from the wellbore region to a petroleum refinery;and, (iii) to a crude oil before or during the processing of a crude oil before it arrives at apetroleum refinery, for example, to a crude oil being blended with a different type of crude oil,and / or hydrocarbon fluid, to form a crude oil blend.Suitably, in in the method of the first and second aspects and / or use of the third and fourthaspects, when a combination of Additive A and Additive B is added to a crude oil, Additive Amay be added to a crude oil at the same one or more crude oil production and / or processingstages as Additive B, or Additive A may be added to a crude oil at a different one or more crudeoil production and / or processing stages than Additive B. Preferably, Additive A and AdditiveB are added to a crude oil at the same one or more crude oil production and / or processing stages.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,when a combination of Additive A and Additive B is added to a crude oil, Additive A andAdditive B may be added essentially simultaneously to a crude oil, or Additive A and AdditiveB may be added sequentially to a crude oil. Preferably, Additive A is added to a crude oilessentially simultaneously with Additive B. More preferably, Additive A and Additive B arein the form of a single additive package.Additive A and / or Additive B may be added to a crude oil by techniques well known to thoseskilled in the art, for example, the additive(s) may be blended into a crude oil, the additive(s)may be introduced into flowlines transporting a crude oil, the additive(s) may be injected intoa crude oil, for example, into a crude oil reservoir via the wellbore.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil is at ambient temperature (i.e. at a temperature of its immediate surroundings andwithout application of heat from an additional external heat source). Crude oil in a crude oilreservoir may be at temperature of up to 150 °C. The transportation, storage and processing ofcrude oil before the crude oil is refined at a petroleum refinery is dependent upon geographicallocation.Suitably, in the method of the first and second aspects and / or use of the third and fourth aspects,the crude oil is at a temperature of less than 40, preferably less than or equal to 35, °C.PF2019M006 / FF11Suitably, in any one of the first to fourth aspects of the invention, the poly(butylenyl)substituent group of greater than or equal to 55, preferably greater than or equal to 60, morepreferably greater than or equal to 65, mass % of said one or more 4-poly(butylenyl)benzenesulphonic acid(s) of Additive A, based on the total mass of all said one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equal to 32 total carbon atoms insaid substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(butylenyl)substituent group of less than or equal to 35, preferably less than or equal to 30, more preferablyless than or equal to 25, more preferably less than or equal to 20, mass % of said one or more4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the total mass of all saidone or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equal to 60 totalcarbon atoms in said substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(butylenyl)substituent group of from 40 to 70, preferably 40 to 65, mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the total mass of all said oneor more 4-poly(butylenyl)benzene sulphonic acid(s), has from 32 to 56 total carbon atoms insaid substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(butylenyl)substituent group of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of AdditiveA includes a poly(butylenyl) substituent group having 32, 36, 40, 44 and / or 48, preferably 32,36 and / or 40, total carbon atoms, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, Additive A has a numberaverage molecular weight (Mn) of from 550 to 800 daltons, as determined by the liquid-liquidextraction and potentiometric titration method described herein, preferably a number averagemolecular weight (Mn) of 550 to 800 daltons and a polydispersity index of 1.1. to 1.5.PF2019M006 / FF12Suitably, in any one of the first to fourth aspects of the invention, the poly(butylenyl)substituent group of said one or more 4-poly(butylenyl)benzene sulphonic acids of Additive Ais derived from the polymerization of but-1-ene.Suitably, the poly(butylenyl) substituent group of said one or more 4-poly(butylenyl)benzenesulphonic acid(s), Additive A, has a branched chain structure. By “branched chain structure”we mean the poly(butylenyl) substituent group consists of a branched chain butanediylrepeating radical. The poly(butylenyl) substituent group may be regarded as consistingessentially of a relatively long straight acyclic alkyl chain bonded to the benzene ring and saidalkyl chain is further substituted by two or more methyl and / or ethyl groups along the lengthof the chain (i.e. the branching is along the relatively long alkyl chain by virtue of pendantmethyl and / or ethyl substituent groups). It has been found that when Additive A includes sucha branched chain poly(butylenyl) substituent group, then this typically further reduces foulingby the feedstock, asphaltene agglomeration (or flocculation) and / or asphaltene precipitation inand / or from the feedstock when the feedstock is heated at an elevated temperature, comparedto the use of poly(alkylenyl)benzene sulphonic acid additive(s) in which the poly(alkylenyl)substituent group is an essentially straight carbon chain.Suitably, in any one of the first to fourth aspects of the invention, a highly preferred AdditiveA comprises one or more 4-poly(butylenyl)benzene sulphonic acids, wherein thepoly(butylenyl) substituent group is derived by polymerising but-1-ene, the poly(butylenyl)substituent group has a branched chain structure, the poly(butylenyl) substituent group ofgreater than or equal to 55 mass % of said one or more 4-poly(butylenyl)benzene sulphonicacid(s) has greater than or equal to 32 total carbon atoms in said substituent group, thepoly(butylenyl) substituent group of from 40 to 65 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) has from 32 to 56 total carbon atoms in saidsubstituent group, and the poly(butylenyl) substituent group comprises a poly(butylenyl)substituent group having 32, 36 and / or 40 total carbon atoms. Preferably, in such a highlypreferred Additive A, Additive A has a number average molecular weight (Mn) of from 550 to800 daltons and a polydispersity index of from 1.1 to 1.5.Suitably, in any one of the first to fourth aspects of the invention, the poly(propylenyl)substituent group of greater than or equal to 55, preferably greater than or equal to 60, more PF2019M006 / FF13preferably greater than or equal to 65, more preferably greater than or equal to than 70, evenmore preferably greater than or equal to than 75, mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the total mass of all saidone or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equal to 21 totalcarbon atoms in said substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(propylenyl)substituent group of less than or equal to 30, preferably less than or equal to 25, more preferablyless than or equal to 20, mass % of said one or more 4-poly(propylenyl)benzene sulphonicacid(s) of Additive B, based on the total mass of all said one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equal to 30 total carbon atomsin said substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(propylenyl)substituent group of from 60 to 95, preferably 65 to 95, more preferably 67 to 90, mass % ofsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on thetotal mass of all said one or more 4-poly(propylenyl)benzene sulphonic acid(s), has from 21 to27 total carbon atoms in said substituent group, as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, the poly(propylenyl)substituent group of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) of AdditiveB includes a poly(propylenyl) substituent group having 21, 24 and / or 27 total carbon atoms,as determined by GC.Suitably, in any one of the first to fourth aspects of the invention, Additive B has a numberaverage molecular weight (Mn) of 400 to 600 daltons, as determined by the liquid-liquidextraction and potentiometric titration method described herein.Suitably, in any one of the first to fourth aspects of the invention, the poly(propylenyl)substituent group of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) of AdditiveB is derived from the polymerization of prop-1-ene.PF2019M006 / FF14Suitably, the poly(propylenyl) substituent group of said one or more poly(propylenyl)benzenesulphonic acids, Additive B, has a branched chain structure, i.e. the poly(propylenyl)substituent group consists of the branched propanediyl repeating radical. The poly(propylenyl)substituent group may be regarded as consisting essentially of a relatively long straight acyclicalkyl chain bonded to the benzene ring and said alkyl chain is further substituted by two ormore methyl groups along the length of the chain (i.e. the branching is along the relatively longalkyl chain by virtue of pendant methyl substituent groups).Suitably, in any one of the first to fourth aspects of the invention, a highly preferred AdditiveB comprises one or more 4-poly(propylenyl)benzene sulphonic acids, wherein thepoly(propylenyl) substituent group is derived by polymerising prop-1-ene, the poly(propylenyl)substituent group has a branched chain structure, the poly(propylenyl) substituent group ofgreater than or equal to 60 mass % of said one or more 4-poly(propylenyl)benzene sulphonicacid(s) has greater than or equal to 21 total carbon atoms in said substituent group, thepoly(propylenyl) substituent group of from 65 to 95 mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) has from 21 to 27 total carbon atoms in saidsubstituent group, and the poly(propylenyl) substituent group includes a poly(propylenyl)substituent group having 21, 24 and / or 27 total carbon atoms. Preferably, in such a highlypreferred Additive B, Additive B has a number average molecular weight (Mn) of from 400 to600 daltons.Suitably, when a combination of Additive A and Additive B is used in any one of the first tofourth aspects of the invention, the mass:mass ratio of Additive A to Additive B is in the rangeof 20:1 to 1:20, such as 10:1 to 1:10, preferably 3:1 to 1:3. Most preferably, Additive A is usedin an amount in excess of Additive B and the mass:mass ratio of Additive A to Additive B isin the range of 20:1 to 1:1, such as 10:1 to 1:1, preferably 3:1 to 1:1.Suitably, Additive A, Additive B, and a combination of Additive A and Additive B, are eachindependently soluble or dispersible in the crude oil.DefinitionsPF2019M006 / FF15In this specification, the following words and expressions, if and when used, shall have themeanings ascribed below:“Active ingredients” or “(a.i.)” refers to additive material that is not diluent or solvent;“comprising” or any cognate word specifies the presence of stated features, steps, or integersor components, but does not preclude the presence or addition of one or more other features,steps, integers, components or groups thereof. The expressions “consists of” or “consistsessentially of” or cognates may be embraced within “comprises” or any cognate word. Theexpression “consists essentially of” permits inclusion of substances not materially affecting thecharacteristics of the composition to which it applies. The expression “consists of” or cognatesmeans only the stated features, steps, integers components or groups thereof are present towhich the expression refers;“Ashless” in relation to an additive means the additive does not include a metal;“Ash-containing” in relation to an additive means the additive includes a metal;“Crude oil” means the hydrocarbon fossil fuel oil located underground which is extracted andrefined in a petroleum refinery operation at a petroleum refinery. The term “crude oil”embraces a single type of crude oil or a crude oil blend comprising two or more different typesof crude oil. Crude oil embraces intermediate (light) crude oils, medium crude oils, heavycrude oils and shale oils;“Crude oil having an asphaltene content” means a crude oil, as defined herein, which includesasphaltenes;“Capacity of a crude oil to solvate and / or disperse asphaltenes” means the ability of a crudeoil to solvate and / or disperse asphaltenes. The capacity and enhanced capacity of a crude oilto solvate and / or disperse asphaltenes is assessed by the crude oil asphaltene stability test asdescribed herein;PF2019M006 / FF16“Enhancing the capacity of a crude oil to solvate and / or disperse asphaltenes” meansincreasing the ability of a crude oil to solvate and / or disperse asphaltenes when such abilityis lowered upon pressure changes, compositional or other mechanical or physical processingoperations of the crude oil (e.g. forming a crude oil blend from two or more different types ofcrude oil). The enhanced capacity may permit increased amounts of asphaltenes to besolvated and / or dispersed in a crude oil. Alternatively, or additionally, the enhancedcapacity may permit formation of a crude oil, or formation of a crude oil blend, having adefined asphaltene content wherein the asphaltenes are more stably solvated and / ordispersed (i.e. asphaltene precipitation from and / or agglomeration in the crude oil isreduced);“Increasing the solubility and / or dispersibility of asphaltenes in a crude oil” meansincreasing the solubility and / or dispersibility of asphaltenes in a crude oil when suchsolubility and / or dispersibility is lowered upon pressure changes, compositional or othermechanical or physical processing operations of the crude oil (e.g. forming a crude oil blend fromtwo or more different types of crude oil). The increased solubility and / or dispersibility isassessed by the crude oil asphaltene stability test as described herein;“Hydrocarbon fluid” means a hydrocarbon liquid or oil which is not a crude oil;“Petroleum refinery operation” means any process which is, or can be, employed in refininga petroleum feedstock (e.g. a crude oil), such as any process employed in an oil refineryoperation. Petroleum refining operation embraces any process which is, or can be,employed in refining a crude oil, crude oil blends comprising two or more different typesof crude oils and the further refining of fractions obtained from refining crude oil and crudeoil blends. Petroleum refinery operations typically include, but are not limited to, thefollowing processing units, components and / or apparatus: a desalting unit to remove inorganicsalts from the feedstock (i.e. crude oil); heat transfer components such as a heat exchanger, afurnace, a crude preheater, a coker preheater, to heat the petroleum feedstock; an atmosphericdistillation unit to distil the feedstock (i.e. crude oil) into various fractions; a vacuumdistillation unit to further distil the heavy bottom fractions from the atmospheric distillationunit; a catalytic cracking unit (e.g. fluid catalytic cracking unit) to break larger molecules intosmaller, lighter hydrocarbon fractions; a catalytic hydrocracking unit to upgrade heavier PF2019M006 / FF17aromatic and unsaturated fractions from the distillation units to gasoline, jet fuel and gasoil; avisbreaker unit to upgrade the heavy bottom fractions from the vacuum distillation unit bythermally cracking them into lighter hydrocarbon fractions; a coking unit (e.g. delayed coking,fluid coking, flexi-coking unit) to thermally crack very heavy residual oil fractions from thedistillation units, especially vacuum distillation unit, to end-products, such as petroleum coke,naptha and diesel oil by-products; a hydrotreater to desulfurize fractions from the distillationunits; a catalytic reforming unit to convert desulfurized fractions to higher-octane molecules;an isomerization unit to convert linear molecular fractions into higher-octane branchedmolecular fractions;“Refineable petroleum feedstock” means a petroleum feedstock which is refined in a petroleumrefinery operation at a petroleum refinery and, in the context of the invention, includes a crudeoil. The term “refineable petroleum feedstock” does not include the ultimate refinedcommercial end-products of a petroleum refinery operation which are not subjected to a furtherrefining operation, such as gasoline and diesel fuels, light and heavy naphtha, kerosene, heavyfuel oils, and lubricating oils.“Refineable petroleum feedstock having an asphaltene content” means a refineable petroleumfeedstock, as defined herein, which includes asphaltenes;“Hydrocarbyl group” means a univalent radical that contains hydrogen and carbon atoms onlyand it is bonded to the remainder of the compound directly via a single carbon atom. The term“hydrocarbyl group” includes “alkyl”, “alkylenyl”, “alkenyl”, “allyl” and “aryl” groups.Preferably, the hydrocarbyl group is an aliphatic hydrocarbyl group, more preferably thehydrocarbyl group is a saturated aliphatic hydrocarbyl group, even more preferably a branchedchain saturated aliphatic hydrocarbyl group, even more preferably a branched-chain alkylgroup, even more preferably a branched-chain acyclic alkyl group;“Alkyl group” means a univalent alkyl radical (i.e. a monovalent hydrocarbon group containingno double or triple bonds) which is bonded to the remainder of the compound directly via asingle carbon atom. Preferably, the alkyl group is a branched-chain acyclic alkyl group. PF2019M006 / FF18“Alkylene” is synonymous with “alkanediyl” and means a bivalent saturated hydrocarbonradical derived from an alkane by removal of a hydrogen atom from two different carbon atoms(i.e. a divalent hydrocarbon radical containing no double or triple bonds); it may be linear orbranched.“Poly(alkylene)” is synonymous with “poly(alkene)” and means a polymer containing theappropriate alkanediyl repeating radical. Such polymers may be formed by polymerization ofthe appropriate alkene (e.g. poly(butylene) may be formed by polymerizing but-1-ene, but-2-ene and / or 2-methyl propene; and poly(propylene) may be formed by polymerizing propene).“Poly(alkylenyl)” substituent group means a univalent polymer substituent group containingthe appropriate alkanediyl repeating radical which is bonded to the rest of the compound via asingle carbon atom. Suitably, a poly(alkylenyl) group may be formed from the correspondingpoly(alkylene) (e.g. a poly(butylenyl) group may be formed from poly(butylene), apoly(propylenyl) group may be formed from poly(propylene);Reference to a group or compound being a particular polymer (e.g. poly(propylenyl) group,poly(butylenyl) group, poly(butylene), poly(propylene)) encompasses polymers thatpreferably consist of the respective alkanediyl repeating radical, but also less preferablythose which contain primarily the respective alkanediyl repeating radical along withnegligible amounts of other substitutions and / or interruptions along the polymer chain. Inother words, reference to a group being a poly(butylenyl) group or poly(propylenyl) in itsbroadest aspect does not require that the group consist of 100% butanediyl or 100 %propanediyl, respectively, repeating radicals without, for example, any linking groups,substitutions, or impurities. Such impurities or other substituents may be present inrelatively minor amounts provided they do not materially affect the performance of theadditive compared with the same additive containing the respective alkanediyl repeatingradical at 100% purity;“Alkene” is synonymous with “alkylene” and means a hydrocarbon compound which includesone or more carbon to carbon double bonds, such as propylene or propene, prop-1ene, butyleneor butene, and but-1-ene;PF2019M006 / FF19“Alkenyl group” means a monovalent hydrocarbon radical which includes one or more carbonto carbon double bonds and is bonded to the remainder of the compound directly via a singlecarbon atom;“halo” or “halogen” includes fluoro, chloro, bromo and iodo;“oil-soluble” or “oil-dispersible”, or cognate terms, used herein do not necessarily indicate thatthe compounds or additives are soluble, dissolvable, miscible, or are capable of beingsuspended in a crude oil in all proportions. These do mean, however, that Additive A, AdditiveB and a combination of Additive A and Additive B are, for example, soluble or stablydispersible in a crude oil to an extent sufficient to exert their intended effect. Moreover, theadditional incorporation of other additives may also permit incorporation of higher levels of aparticular additive(s), if desired;“major amount” means in excess of 50 mass %, preferably 60 mass % or more, more preferably70 mass % or more, even more preferably 80 mass % or more, of a composition;“minor amount” means less than 50 mass %, preferably less than or equal to 40 mass %, morepreferably less than or equal to 30 mass %, even more preferably less than or equal to 20mass %, of a composition;“effective amount” in respect of an additive, or combination of additives, means an amount ofsuch additive(s) in a composition that is effective to provide, and provides, the desired technicaleffect;“ppm” means parts per million by mass, based on the total mass of the composition;“TBN” in relation to an additive component or of a composition, means total base number (mgKOH / g) as measured by ASTM D2896;“KV100” means kinematic viscosity at 100oC as measured by ASTM D445;PF2019M006 / FF20Mn means number average molecular weight. Mn of Additive A and Additive B may bedetermined by the liquid-liquid extraction and two-phase potentiometric titration methoddescribed herein. Mn of the poly(butylene) used to synthesise Additive A may be determinedby gel permeation chromatography; Mn of the poly(propylene) used to synthesise Additive Bmay be determined by gas chromatography (GC) using a flame ionization detector (FID) andsimulated distillation in accordance with ASTM D2887, as described herein;Mw means weight average molecular weight. Mw of Additive A and Additive B may bedetermined by gas chromatography (GC) and simulated distillation in accordance with ASTMD2887 using a flame ionization detector (FID), as described herein. Mw of the respectivepoly(butylene) and poly(propylene) used to synthesise Additive A and Additive B may bedetermined by GC using the same method;“Polydispersity index” of a polymeric entity means Mw / Mn of the polymeric entity andrepresents an index of the breadth of molecular weight distribution.The mass % of the poly(butylenyl) substituent group having a particular total number of carbonatoms in Additive A, based on the total mass of the one or more 4-poly(butylenyl)benzenesulphonic acids of Additive A, is determined by measuring the mass distribution of the one ormore 4-poly(butylenyl)benzene sulphonic acids of Additive A by gas chromatography (GC)and simulated distillation in accordance with ASTM D2887 using a flame ionization detector(FID), as described herein;The mass % of the poly(propylenyl) substituent group having a particular total number ofcarbon atoms in Additive B, based on the total mass of the one or more 4-poly(propylenyl)benzene sulphonic acids of Additive B, is determined by measuring the massdistribution of the one or more 4-poly(propylenyl)benzene sulphonic acids of Additive A bygas chromatography (GC) and simulated distillation in accordance with ASTM D2887 using aflame ionization detector (FID), as described herein;All percentages reported are mass % on an active ingredient basis, i.e. without regard to carrieror diluent oil, unless otherwise stated.PF2019M006 / FF21Also, it will be understood that various components used, essential as well as optimal andcustomary, may react under conditions of formulation, storage or use and that the inventionalso provides the product obtainable or obtained as a result of any such reaction.Further, it is understood that any upper and lower quantity, range and ratio limits set forthherein may be independently combined. Accordingly, any upper and lower quantity, range andratio limits set forth herein associated with a particular technical feature of the present inventionmay be independently combined with any upper and lower quantity, range and ratio limits setforth herein associated with one or more other particular technical feature(s) of the presentinvention. Furthermore, any particular technical feature of the present invention, and allpreferred variants thereof, may be independently combined with any other particular technicalfeature(s), and all preferred variants thereof, irrespective of whether such features are presentedas preferred or not.Also, it will be understood that the preferred features of each aspect of the present inventionare regarded as preferred features of each and every other aspect of the present invention.DETAILED DESCRIPTION OF THE INVENTIONAdditive AAdditive A is one or more 4-poly(butylenyl)benzene sulphonic acid(s). The one or more 4-poly(butylenyl)benzene sulphonic acid(s) have a single sulphonic acid group and a singlesubstituent group being the poly(butylenyl) substituent group attached to the para-position ofthe benzene ring with respect to the sulphonic acid group (i.e. the remainder of the benzenering is not substituted and includes hydrogen atoms). It has been found that use of such monosubstituted one or more 4-poly(butylenyl)benzene sulphonic acid(s) typically increases thecapacity of a crude oil to solvate and / or disperse asphaltenes, and / or increases the solubilityand / or dispersancy of asphaltenes in a crude oil, compared to the use of one or more 4-poly(alkylenyl)benzene sulphonic acid additive(s) which also include one or more further alkylsubstituents ortho and / or meta to the poly(alkylenyl) substituent group (i.e. mono-substituted4- poly(butylenyl)benzene sulphonic acid(s) are typically more effective).PF2019M006 / FF22The one or more 4-poly(butylenyl)benzene sulphonic acid(s) (Additive A) includes thesulphonic acid group as the free acid. Additive A is ashless and does not include salts (e.g.metal salts) of the sulphonic acid.Suitably, Additive A is derived from the polymerization of butene, preferably but-1-ene.Typically, Additive A may be synthesized by standard experimental techniques which are wellknown to those skilled in the art, for example, the intermediate one or more 4-poly(butylenyl)benzene(s) having the desired mass % of poly(butylenyl) substituent grouphaving a particular total number of carbon atoms may be synthesized by reacting butene,especially but-1ene, with benzene using a Friedal-Crafts reaction (e.g. using a Friedal-Craftscatalyst such as a slurry of AlCl3 / HCl, at a reduced temperature, such as 3 to 10 °C). Theintermediate one or more 4-poly(butylenyl)benzene(s) may then be sulphonated with asulphonating agent (e.g. oleum, SO2, SO3), using standard techniques, to form the one or more4-poly(butylenyl)benzene sulphonic acid(s) of Additive A having the desired characteristics,especially the desired mass % of poly(butylenyl) substituent group with a particular totalnumber of carbon atoms. Suitably, the integrity of the poly(butylenyl) substituent group of theintermediate one or more poly(butylenyl)benzene(s) (e.g. the mass % of poly(butylenyl)substituent group having a particular total number of carbon atoms) is essentially maintainedduring the sulphonation reaction of the intermediate. Accordingly, the mass % ofpoly(butylenyl) substituent group having a particular total number of carbon atoms in theintermediate one or more 4-poly(butylenyl)benzene(s) is essentially identical to the mass % ofpoly(butylenyl) substituent group having a particular total number of carbon atoms in the oneor more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A.The appropriate poly(butylene) reactant used to form the intermediate one or more 4-poly(butylenyl)benzene(s) may be produced by polymerizing butene, particularly but-1-ene,using an appropriate catalyst system e.g. EtAlCl3 and HCl. A suitable source of butene,particularly but-1-ene, is the Raffinate II stream obtained as a by-product from the synthesis ofpoly(isobutylene), for example as disclosed in US Patent no. 4,952,739. Suitably, thecharacteristics of the poly(butylene) reactant (e.g. Mn, Mw, mass % of poly(butylene) having aparticular number of total carbon atoms) should be substantially the same as the correspondingdesired characteristics of the poly(butylenyl) substituent group in the intermediate one or more PF2019M006 / FF234-poly(butylenyl)benzene(s) and in the one or more 4-poly(butylenyl)benzene sulphonic acid(s)of Additive A. Suitably, a preferred poly(butylene) is obtained by polymerizing but-1-enewherein the poly(butylene) has: (i) a Mn of from 450 to 650, preferably 500 to 600, daltons asmeasured by gel permeation chromatography (see W. W. Yau, J. J. Kirkland and D. D. Bly,“Modern Size Exclusion Liquid Chromatography”, John Wiley and Sons, New York, 1979);(ii) a polydispersity of from 1.1 to 1.5, preferably 1.2 to 1.4; (iii) greater than 55, preferablygreater than 60, mass % of the poly(butylene), based on the total mass of poly(butylene), hasgreater than or equal to 32 total carbon atoms as determined by GC in accordance with ASTMD2887; and, (iv) less than 35 mass % of the poly(butylene), based on the total mass ofpoly(butylene), has greater than or equal to 60 total carbon atoms as determined by GC inaccordance with ASTM D2887.Suitably, a high proportion of the poly(butylenyl) substituent groups of Additive A have arelatively narrow total carbon chain length distribution in which the poly(butylenyl) substituentgroup of greater than or equal to 50, preferably greater than or equal to 55, more preferablygreater than or equal to 60, more preferably greater than or equal to 65, mass % of said one ormore 4-poly(butylenyl)benzene sulphonic acids, based on the total mass of all said one or more4-poly(butylenyl)benzene sulphonic acids, has greater than or equal to 32 total carbon atomsin said substituent group, as determined by GC in accordance with ASTM D2887. Suitably,the poly(butylenyl) substituent group of less than or equal to 35, preferably less than or equalto 30, more preferably less than or equal to 25, more preferably less than or equal to 20, mass %of said one or more 4-poly(butylenyl)benzene sulphonic acids of Additive A, based on the totalmass of all said one or more 4-poly(butylenyl)benzene sulphonic acids, has greater than orequal to 60 total carbon atoms in said substituent group, as determined by GC in accordancewith ASTM D2887.Suitably, the poly(butylenyl) substituent group of from 40 to 70, preferably 40 to 65, mass %of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on thetotal mass of all said one or more 4-poly(butylenyl)benzene sulphonic acid(s), has from 32 to56 total carbon atoms in said substituent group, as determined by GC in accordance with ASTMD2887.PF2019M006 / FF24Suitably, the poly(butylenyl) substituent group of said one or more 4-poly(butylenyl)benzenesulphonic acids includes a poly(butylenyl) substituent group having 32, 36, 40, 44 and / or 48,preferably 32, 36 and / or 40, total carbon atoms.Suitably, Additive A has a number average molecular weight (Mn) of greater than or equal to550, preferably greater than or equal to 600, more preferably greater than or equal to 650,daltons, as determined by the liquid-liquid extraction and two-phase potentiometric titrationmethod described herein.Suitably, Additive A has a number average molecular weight (Mn) of less than or equal to 800,preferably less than or equal to 750, more preferably less than or equal to 700, daltons, asdetermined by the liquid-liquid extraction and two-phase potentiometric titration methoddescribed herein.Suitably, Additive A has a polydispersity index of from 1.1 to 1.5, preferably 1.2 to 1.4.Suitably, the poly(butylenyl) substituent groups of said one or more 4-poly(butylenyl)benzenesulphonic acids have a branched chain structure. In other words, the poly(butylenyl) substituentgroup of said one or more 4-poly(butylenyl)benzene sulphonic acids comprises one or morebranched chain butanediyl repeating radicals.Suitably, the poly(butylenyl) substituent groups of the one or more 4-poly(butylenyl)benzenesulphonic acids comprises poly(butylenyl) substituent groups bonded by the C-2 or C-1position of the poly(butylenyl) group to the para-position of benzene ring.Additive A may be present in the crude oil in an amount of from 1 to 10000, preferably 1 to5000, more preferably 1 to 1000, even more preferably 1 to 500, even more preferably 1 to 100,even more preferably 1 to less than 100, ppm by mass, based on the total mass of the crude oil.Suitably, Additive A, as defined herein, may be represented by one or more compounds ofFormula I PF2019M006 / FF25Formula Iwhere each R1 independently represents a poly(butylenyl) substituent group, as defined herein.Additive A is added to the crude oil before the crude oil is refined in a petroleum refineryoperation at a petroleum refinery. Additive A may be added to the crude oil when the crude oilis at the petroleum refinery and / or before the crude oil arrives at the petroleum refinery.Preferably, Additive A is added to the crude oil before the crude oil arrives at the petroleumrefinery.Suitably, Additive A is added to the crude oil at one or more crude oil production and / orprocessing stages before the crude oil arrives at a petroleum refinery selected from: (i) to acrude oil in a subterranean crude oil reservoir during an extraction process of the crude oil fromthe reservoir, for example, by injecting the additive(s) into the crude oil reservoir via thewellbore; (ii) to a crude oil during the storage of the crude oil, for example, to a crude oil beingstored in storage tanks, which tanks may be located at the wellbore region, or at intermediatelocations between the wellbore region and the petroleum refinery; (iii) to a crude oil during thetransportation of a crude oil, for example, to a crude oil being transported by pipeline, ship,rail, oil tanker, especially to a crude oil being transported from the wellbore region to apetroleum refinery; (iv) to a crude oil before or during the processing of a crude oil before thecrude oil is at a petroleum refinery, for example, to a crude oil being blended with a differenttype of crude oil, and / or hydrocarbon fluid, to form a crude oil blend. Preferably, Additive Ais added to the crude oil at one or more crude oil production process stages before the crude oilis at a petroleum refinery selected from: (i) to a crude oil during the storage of a crude oil atthe wellbore region and locations between the wellbore region and petroleum refinery; (ii) to acrude oil during the transportation of a crude oil being transported from the wellbore region toa petroleum refinery; and, (iii) to a crude oil before or during the processing of a crude oil PF2019M006 / FF26before the crude oil is at a petroleum refinery, for example, to a crude oil being blended with adifferent type of crude oil, and / or hydrocarbon fluid, to form a crude oil blend.Additive A may be added to a crude oil by methods well known to those skilled in the art. Forexample, Additive A may be blended into the crude oil and / or injected into a flowlinetransporting the crude oil.Suitable Additives A for use in the invention are available from Infineum UK Limited.Additive BAdditive B is one or more 4-poly(propylenyl)benzene sulphonic acid(s). The one or more 4-poly(propylenyl)benzene sulphonic acid(s) have a single sulphonic acid group and a singlesubstituent group being the poly(propylenyl) substituent group attached to the para-position ofthe benzene ring with respect to the sulphonic acid group (i.e. the remainder of the benzenering is not substituted and includes hydrogen atoms). It has been found that use of such monosubstituted one or more 4-poly(propylenyl)benzene sulphonic acid(s) typically increases thecapacity of a crude oil to solvate and / or disperse asphaltenes, and / or increases the solubilityand / or dispersancy of asphaltenes in a crude oil.The one or more 4-poly(propylenyl)benzene sulphonic acid(s) includes the sulphonic acidgroup as the free acid. Additive B is ashless and does not include salts (e.g. metal salts) of thesulphonic acid.Suitably, Additive B is derived from the polymerization of prop-1-ene.Typically, Additive B may be synthesized by standard experimental techniques which are wellknown to those skilled in the art. For example, Additive B may be synthesized by analogoustechniques as described herein for Additive A by substituting the poly(butylene) reactant withthe appropriate poly(propylene) reactant. Suitably, the integrity of the poly(propylenyl)substituent group of the intermediate one or more poly(propylenyl)benzene(s) (e.g. the mass %of poly(propylenyl) substituent group having a particular total number of carbon atoms) isessentially maintained during the sulphonation reaction of the intermediate. Accordingly, the PF2019M006 / FF27mass % of poly(propylenyl) substituent group having a particular total number of carbon atomsin the intermediate one or more 4-poly(propylenyl)benzene(s) is essentially identical to themass % of poly(propylenyl) substituent group having a particular total number of carbon atomsin the one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B.The appropriate poly(propylene) reactant used to form the intermediate one or more 4-poly(propylenyl)benzene(s) may be produced by polymerizing propene, using an appropriatecatalyst system e.g. boron trifluoride and water. Suitably, the characteristics of thepoly(propylene) reactant (e.g. Mn, Mw, mass % of poly(butylene) having a particular numberof total carbon atoms) should be substantially the same as the corresponding desiredcharacteristics of the poly(propylenyl) substituent group in the intermediate one or more 4-poly(propylenyl)benzene(s) and in the one or more 4-poly(propylenyl)benzene sulphonicacid(s) of Additive B. Suitably, a preferred poly(propylene) reactant is obtained bypolymerizing prop-1-ene wherein the poly(propylene) has: (i) a Mn of from 250 to 400,preferably 300 to 375, daltons as measured by GC in accordance with ASTM D2887; (ii)greater than 55, preferably greater than 60, mass % of the poly(propylene), based on the totalmass of poly(propylene), has greater than or equal to 21 total carbon atoms as determined byGC in accordance with ASTM D2887; and, (iii) less than 25 mass % of the poly(propylene),based on the total mass of poly(propylene), has greater than or equal to 30 total carbon atomsas determined by GC in accordance with ASTM D2887.Suitably, a high proportion of the poly(propylenyl) substituent groups of Additive B have anarrow total carbon chain length distribution in which the poly(propylenyl) substituent groupof greater than or equal to 55, preferably greater than or equal to 60, more preferably greaterthan or equal to 65, more preferably greater than or equal to 70, even more preferably greaterthan or equal to 75, mass % of said one or more 4-poly(propylenyl)benzene sulphonic acids ofAdditive B, based on the total mass of all said one or more 4-poly(propylenyl)benzenesulphonic acids, has greater than or equal to 21 total carbon atoms in said substituent group, asdetermined by GC in accordance with ASTM D2887. Suitably, the poly(propylenyl)substituent group of less than or equal to 30, preferably less than or equal to 25, more preferablyless than or equal to 20, mass % of said one or more 4-poly(propylenyl)benzene sulphonicacids of Additive B, based on the total mass of all said one or more 4-poly(butylenyl)benzene PF2019M006 / FF28sulphonic acids, has greater than or equal to 30 total carbon atoms in said substituent group, asdetermined by GC in accordance with ASTM D2887.Suitably, the poly(propylenyl) substituent group of from 60 to 95, preferably 65 to 95, morepreferably 70 to 90, mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s)of Additive B, based on the total mass of all said one or more 4-poly(butylenyl)benzenesulphonic acid(s), has from 21 to 27 carbon atoms in said substituent group, as determined byGC in accordance with ASTM D2887.Suitably, the poly(propylenyl) substituent group of said one or more poly(propylenyl)benzenesulphonic acids of Additive B includes a poly(propylenyl) substituent group having 21, 24and / or 27 total carbon atoms.Suitably, Additive B has a number average molecular weight (Mn) of greater than or equal to400, preferably greater than or equal to 450, more preferably greater than or equal to 475,daltons, as determined by the liquid-liquid extraction and two-phase potentiometric titrationmethod described herein.Suitably, Additive B has a number average molecular weight (Mn) of less than or equal to 600,preferably less than or equal to 550, more preferably less than or equal to 525, daltons asdetermined by the liquid-liquid extraction and two-phase potentiometric titration methoddescribed herein.Suitably, Additive B has a polydispersity index of from 1.1 to 1.5.Suitably, the poly(propylenyl) substituent group of said one or more 4-poly(propylenyl)benzene sulphonic acids have a branched chain structure. In other words, thepoly(propylenyl) substituent group comprises one or more branched chain propanediylrepeating radicals.Suitably, the poly(propylenyl) substituent group of the one or more 4-poly(propylenyl)benzenesulphonic acids comprises poly(propylenyl) substituent groups bonded by the C-2 or C-1position of the poly(propylenyl) group to the para-position of the benzene ring. PF2019M006 / FF29Suitably, Additive B, as defined herein, may be represented by one or more compounds ofFormula IIFormula IIwherein each R2 independently represents a poly(propylenyl) substituent group as definedherein.Additive B may be present in the crude oil in an amount of from 1 to 10000, preferably 1 to5000, more preferably 1 to 1000, even more preferably 1 to 500, even more preferably 1 to 100,even more preferably 1 to less than 100, ppm by mass, based on the total mass of the crude oil.Additive B is added to the crude oil before the crude oil is refined in a petroleum refineryoperation at a petroleum refinery. Additive B may be added to the crude oil when the crude oilis at the petroleum refinery and / or before the crude oil arrives at the petroleum refinery.Preferably, Additive B is added to the crude oil before the crude oil arrives at the petroleumrefinery.Suitably, Additive B is added to the crude oil at one or more crude oil production and / orprocessing stages before the crude oil arrives at a petroleum refinery selected from: (i) to acrude oil in a subterranean crude oil reservoir during an extraction process of the crude oil fromthe reservoir, for example, by injecting the additive(s) into the crude oil reservoir via thewellbore; (ii) to a crude oil during the storage of the crude oil, for example, to a crude oil beingstored in storage tanks, which tanks may be located at the wellbore region, or at intermediatelocations between the wellbore region and the petroleum refinery; (iii) to a crude oil during thetransportation of a crude oil, for example, to a crude oil being transported by pipeline, ship,rail, oil tanker, especially to a crude oil being transported from the wellbore region to a PF2019M006 / FF30petroleum refinery; (iv) to a crude oil before or during the processing of a crude oil before thecrude oil is at a petroleum refinery, for example, to a crude oil being blended with a differenttype of crude oil, and / or hydrocarbon fluid, to form a crude oil blend. Preferably, Additive Bis added to the crude oil at one or more crude oil production process stages before the crude oilis at a petroleum refinery selected from: (i) to a crude oil during the storage of a crude oil atthe wellbore region and locations between the wellbore region and petroleum refinery; (ii) to acrude oil during the transportation of a crude oil being transported from the wellbore region toa petroleum refinery; and, (iii) to a crude oil before or during the processing of a crude oilbefore the crude oil is at a petroleum refinery, for example, to a crude oil being blended with adifferent type of crude oil, and / or hydrocarbon fluid, to form a crude oil blend.Additive B may be added to a crude oil by methods well known to those skilled in the art. Forexample, Additive B may be blended into a crude oil and / or injected into a flowline transportingthe crude oil.Suitable Additives B for use in the invention are available from Infineum UK Limited.Additive B, when used in combination with Additive A, may be added to the crude oilsimultaneously or sequentially to Additive A. For example, a blend containing both ofAdditives A and B may be added to the crude oil; Additive A may be added to the crude oilinitially followed by Additive B; or, Additive B may be added to the crude oil initially followedby Additive A. In a preferred embodiment when a combination of Additive A and Additive Bis also added to the crude oil, both Additive A and Additive B are added to the crude oilessentially simultaneously.Additive B, when used in combination with Additive A, may be added to the crude oil at thesame one or more crude oil production and / or processing stages before the crude oil arrives ata petroleum refinery as Additive A, or Additive B may be added to the crude oil at a differentone or more crude oil production and / or processing stages before the crude oil arrives at apetroleum refinery as Additive A. Preferably, Additive B is added to the crude oil at the sameone or more crude oil production and / or processing stages as Additive A, more preferablyAdditive A and Additive B are added essentially simultaneously to the crude oil at the samestage of the refinery operation.PF2019M006 / FF31Suitably, when a combination of Additive A and Additive B is used, the combined treat rate ofAdditive A and Additive B is from 2 to 10000, preferably 2 to 5000, more preferably 2 to 1000,more preferably 2 to 200, even more preferably 2 to less than 100, ppm by mass, based on thetotal mass of the crude oil.Suitably, when a combination of Additive A and Additive B is used, the mass:mass ratio ofAdditive A to Additive B is in the range of 20:1 to 1:20, such as 10:1 to 1:10, preferably 3:1 to1:3. More preferably, Additive A is used in an amount in excess of Additive B and themass:mass ratio of Additive A to Additive B is in the range of 20:1 to 1:1, such as 10:1 to 1:1,preferably 3:1 to 1:1.COMPOSITIONSAdditive A and / or Additive B may be used in compositions; the compositions may furthercontain a hydrophobic oil solubilizer and / or a dispersant for the additive(s). Such solubilizersmay include, for example, surfactants and / or carboxylic acid solubilizers.The compositions may further include, for example, viscosity index improvers, anti-foamants,antiwear agents, demulsifiers, anti-oxidants, and other corrosion inhibitors.EXAMPLESThe present invention is illustrated by but in no way limited to the following examples.Liquid-Liquid Extraction and Potentiometric Titration to determine MnThe Mn of a 4-poly(alkylenyl)benzene sulphonic acid, such as Additive A and Additive B asdefined herein, is determined by the following method.The 4-poly(alkylenyl)benzene sulphonic acid (typically 3g) is weighed, the sample weight ingrams is recorded (sample weight recorded as P1) and the sample dissolved in propan-2-ol (15ml). An alcoholic solution of phenolphthalein indicator is added to the 4-PF2019M006 / FF32poly(alkylenyl)benzene sulphonic acid / propan-2-ol solution and the solution titrated withaqueous sodium hydroxide (1 N) until the indicator turns pink (the volume of sodium hydroxideadded is recorded as V1). Aqueous hydrochloric acid (1 N) is then added dropwise to thissolution until the pink colour of the indicator disappears. The resulting solution, taking intoaccount the combined volume of aqueous sodium hydroxide and aqueous hydrochloric acidadded to the original 4-poly(alkylenyl)benzene sulphonic acid / propan-2-ol solution, is madeup to form a solution containing a volume to volume ratio of water to propan-2-ol of 1:1, bythe addition of the minimum volume of water if the combined volume of aqueous sodiumhydroxide and aqueous hydrochloric acid added is less than 15 ml or by the addition of theminimum volume of propan-2-ol if the combined volume of aqueous sodium hydroxide andaqueous hydrochloric acid added is more than 15 ml. The resulting solution is extracted withpentane (1 x 40 mL and then 2 x 20 mL) and the combined pentane extracts washed with awater / propan-2-ol solution (1:1 ratio by volume, 3 x 15 ml). The combined water / propan-2-olextracts are warmed at 60 ⁰ C to remove any traces of pentane, allowed to cool to roomtemperature and made up to 100 mL with a water / propan-2-ol solution (1:1 by volume) to formthe final poly(alkylenyl)benzene sulphonic acid-water / propan-2-ol solution.40 mL of the final poly(alkylenyl)benzene sulphonic acid-water / propan-2-ol solution istransferred to an empty pre-weighed beaker (empty beaker weight recorded in grams as P2),the solution evaporated to dryness under a stream of nitrogen at 70 ⁰ C, the product dried in anoven at 130-150 ⁰ C for at least 1 hour and then cooled to room temperature in a desiccator for1 hour. The weight of the beaker and sample in grams is recorded as P3. A further 40 mL of thefinal poly(alkylenyl)benzene sulphonic acid-water / propan-2-ol solution is transferred to aseparating funnel, water (75 mL) and p-toluidine hydrochloride (2 g) added thereto and theresulting solution extracted with dichloromethane (1 x 40 mL and 2 x 20 ml). The combineddichloromethane extracts are added to a water / propan-2-ol solution (100 mL, 3:7 by volume)to form a two-phase solution. The two-phase solution is stirred and potentiometrically titratedagainst aqueous sodium hydroxide (0.1 N) using a Metrohm titration unit set to titrate at 20microlitres; the volume of aqueous sodium hydroxide added to reach the end point is recordedas V2.To calibrate the potentiometric two-phase titration method, 40 mL of a water / propan-2-ol (1:1by volume) solution not including any sample is transferred to a separating funnel, water (75 PF2019M006 / FF33mL) and p-toluidine hydrochloride (2 g) added thereto and the resulting solution extracted withdichloromethane (1 x 40 mL and 2 x 20 ml). The dichloromethane extracts are added to awater / propan-2-ol solution (100 mL, 3:7 by volume) to form a two-phase solution. The twophase solution is stirred and potentiometrically titrated against aqueous sodium hydroxide (0.1N) using a Metrohm titration unit; the volume of aqueous sodium hydroxide added to reach theend point is recorded as V3.The number average molecular (Mn) of the 4-poly(alkylenyl)benzene sulphonic acid iscalculated by the following equation:Mn = (((𝑃3 − 𝑃2) −𝐴 × 𝑃1 × 71100 × 49 × 2.5) ×1000(𝑉2 − 𝑉3) × 𝑁) − 22wherein:P3 = weight (g) of beaker plus sample;P2 = weight (g) of empty beaker;A = mineral acidity of the 4-poly(alkylenyl)benzene sulphonic acid expressed as mass % ofsulphuric acid as determined from ASTM D4711;P1 = sample weight (g);V2 = volume (ml) of NaOH (0.1N) added to the sample during potentiometric titration;V3 = volume (ml) of NaOH (0.1N) added to two-phase solution during calibration ofpotentiometric titration;N = Normality of sodium hydroxide solution use in potentiometric titration which is 0.1.Gel Permeation Chromatography to determine Mn of Poly(butylene)Mn of poly(butylene) is determined by gel permeation chromatography (see W. W. Yau, J. J.Kirkland and D. D. Bly, “Modern Size Exclusion Liquid Chromatography”, John Wiley andSons, New York, 1979) using a MIXED-D PLgel HPLC column from Agilient TechnologiesInc, a refractive index detector (30 °C), a tetrahydrofuran mobile phase of 1 ml / minute andcalibrated with an EasiCal PS-2 polystyrene standard from Agilient Technologies Inc.Gas Chromatography and FID in accordance with ASTM D2887PF2019M006 / FF34Mw of Additive A, Mw of Additive B, Mw of the poly(butylene) used to synthesise Additive A,and Mw and Mn of the poly(propylene) used to synthesise Additive B, is determined by gaschromatography (GC) and simulated distillation using a flame ionization detector (FID) inaccordance with ASTM D2887. Suitably, this analytical method yields the mass % distributionof poly(alkylenyl) substituent groups in Additive A and Additive B, respectively, having aspecific total number of carbon atoms. Suitably, this analytical method yields the mass %distribution of poly(alkylene) chains in poly(butylene) and in poly(propylene) having a specifictotal number of carbon atoms.The ASTM D2887 equipment and operating conditions are as follows: the chromatograph isnot equipped with cryogenics since the starting temperature is 35 ⁰ C; samples are diluted inpentane instead of carbon disulfide; the equipment is calibrated using reference Boiling PointCalibration Sample 1 from Agilent Technologies Inc, Part Number 5080-8716, dissolved incarbon disulfide (i.e. a n-parrafinic sample of known composition); the gas chromatograph is aHewlett Packard 5890 Series 2 Plus Chromatograph having a Restek MXT-1HT SimDistcolumn, length 5 m, diameter 0.53 mm, film thickness 10 μm; the carrier gas is helium and anoutput flow of 6 ml / minute; the detector is a flame ionization detector; the oven temperature isset at 35 ⁰ C for 2 minutes then heated at a rate of 8 ⁰ C / min to reach 410 ⁰ C and then held atthis temperature for 15 minutes; injector type: on-column; the initial injector temperature is 38⁰ C and final temperature is 413 ⁰ C (injector temperature = oven temperature +3 ⁰ C); the FIDdetector temperature is 400 ⁰ C.COMPONENTSThe following additive components and crude oil were used.Component (A)Component A represents Additive A as defined herein.(i) Synthesis of Poly(butylene)PF2019M006 / FF35In a continuous process, a Raffinate II stream is polymerised using a concentrated hydrochloricacid and ethyl aluminium dichloride catalyst system (mass to mass ratio of HCl to EtAlCl2 of3:1) in Isopar-L solvent at a temperature of 25 to 45 °C for 30 minutes. The reactor product iswashed with water and sodium hydroxide, and the product stripped of unreacted C4butylene / butanes (temperature of 200 to 230 °C, pressure less than 0.5 bar) to producepoly(butylene) having: a Mn of 540 daltons as measured by gel permeation chromatography; apolydispersity index of 1.3; greater than 55 mass % of the poly(butylene), based on the totalmass of poly(butylene), has greater than or equal to 32 total carbon atoms as determined byGC in accordance with ASTM D2887.(ii) Synthesis of 1-poly(butylenyl)benzeneIn a continuous process, poly(butylene) (1 mole) from step (i) and benzene (14.5 mole) arereacted in the presence of an aluminium trichloride / hydrochloric acid catalyst slurry at atemperature of 3 to 8°C for 45 minutes. The sludge is removed from the reactor and theremaining liquid phase in the reactor is washed multiple times with aqueous sodium hydroxide(7 wt %) at a temperature of 90 to 100 °C, then washed with water and then the organic liquidphase distilled at 160 to 170 °C (atmospheric pressure) to remove excess benzene and toremove the lower boiling 1-poly(butylenyl)benzenes in which the poly(butylenyl) substituentgroup has less than 16 total carbon atoms. The desired 1-poly(butylenyl)benzene product isobtained by distillation at 320 °C under reduced pressure (20 to 40 mm Hg) to produce 1-poly(butylenyl)benzenes having: (i) a polydispersity of 1.3; (ii) the poly(butylenyl) substituentgroup of greater than or equal to 55 mass % of said one or more 1-poly(butylenyl)benzeneshas greater than or equal to 32 total carbon atoms in said substituent group as determined byGC in accordance with ASTM D2887; (iii) the poly(butylenyl) substituent group of from 40 to70 mass % of said one or more 1-poly(butylenyl)benzenes has from 32 to 56 total carbon atomsin said substituent group as determined by GC in accordance with ASTM D2887; (iv) thepoly(butylenyl) substituent group of less than or equal to 25 mass % of said one or more 1-poly(butylenyl)benzenes has greater than or equal to 60 total carbon atoms in said substituentgroup as determined by GC in accordance with ASTM D2887; (v) the poly(butylenyl)substituent group comprises a poly(butylenyl) substituent group having 32, 36 and / or 40 totalcarbon atoms; and, (vi) the poly(butylenyl) substituent group comprises poly(butylenyl)substituents having a branched chain structure.PF2019M006 / FF36(iii) Synthesis of 4-poly(butylenyl)benzene sulphonic acidA reactor is charged with the 1-poly(butylenyl)benzene product from step (ii), an excess ofsulfur dioxide introduced with stirring (volume ratio of sulfur dioxide to 4-poly(butylenyl)benzene of 4:1) while maintaining the reaction temperature between 0 and -5 °C, afterwhich an excess of sulfur trioxide (mole ratio of sulfur trioxide to 4-poly(butylenyl)benzene of 120:1) is introduced while maintaining the reaction temperaturebetween 0 and -5 °C. The reaction mixture is then allowed to stand for 1 hour at a temperatureof -2 to 5 °C. The excess sulfur dioxide / sulfur trioxide is stripped off at 120 ⁰ C at 0.1 bar andthe reaction mixture cooled to 60 °C to yield the title compound. The title compound may bediluted in diluent oil, such as SN80 (commercially available from Repsol).The isolated 4-poly(butylenyl)benzene sulphonic acid has: (i) a Mn of between 600 to 700daltons; (ii) a polydispersity of 1.3; (iii) the poly(butylenyl) substituent group of greater thanor equal to 55 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) hasgreater than or equal to 32 total carbon atoms in said substituent group as determined by GC inaccordance with ASTM D2887; (iv) the poly(butylenyl) substituent group of from 40 to 70mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) has from 32 to 56 totalcarbon atoms in said substituent group as determined by GC in accordance with ASTM D2887;(v) the poly(butylenyl) substituent group of less than or equal to 25 mass % of said one or more4-poly(butylenyl)benzene sulphonic acid(s) has greater than or equal to 60 total carbon atomsin said substituent group as determined by GC in accordance with ASTM D2887; (vi) thepoly(butylenyl) substituent group comprises a poly(butylenyl) substituent group having 32, 36and / or 40 total carbon atoms; and, (vii) the poly(butylenyl) substituent group comprisespoly(butylenyl) substituents having a branched chain structure.Suitable Additives A are available from Infineum UK Ltd, for example, comprising 83 mass %a.i. of 4-poly(butylenyl)benzene sulphonic acids.Component (B)Component B represents Additive B as defined herein. PF2019M006 / FF37(i) Synthesis of Poly(propylene)A sealed reactor is charged with propene, boron trifluoride catalyst and water as cocatalyst(molar ratio of boron trifluoride to water of 1:2) at 24 to 28 °C and a pressure of 16 bar, andthe resulting reaction mixture agitated for 1 hour. The reaction mixture is then heated to 50 °C(atmospheric pressure) initially, and then to 90 to 120 °C under vacuum (60 mbar) to distil offresidual propane, boron trifluoride and boron trifluoride / water complex. The residual purifiedpoly(propylene) remaining in the reactor is cooled and stored at 60 °C, the poly(propylene) has:(i) a Mn of 340 daltons as measured by GC in accordance with ASTM D2887; (ii) greater than65 mass % of the poly(propylene), based on the total mass of poly(propylene), has greater thanor equal to 21 total carbon atoms as determined by GC in accordance with ASTM D2887; and,(iii) less than 25 mass % of the poly(propylene), based on the total mass of poly(propylene),has greater than or equal to 30 total carbon atoms as determined by GC in accordance withASTM D2887.(ii) Synthesis of 1-poly(propylenyl)benzeneThe title compound is synthesised from poly(propylene) obtained from step (i) using the sameprocedure to form 1-poly(butylenyl)benzene as described in step (ii) for Component A using amole to mole ratio of benzene to poly(propylene) of 7.5:1.The 1-poly(propylenyl)benzene product is obtained by distillation at 295 °C under reducedpressure (20 to 40 mm Hg) to produce 1-poly(propylenyl)benzenes wherein: (i) thepoly(propylenyl) substituent group of greater than or equal to 60 mass % of said one or more1-poly(propylenyl)benzenes has greater than or equal to 21 total carbon atoms in saidsubstituent group as determined by GC in accordance with ASTM D2887; (ii) thepoly(propylenyl) substituent group of from 65 to 90 mass % of said one or more 1-poly(propylenyl)benzenes has from 21 to 27 total carbon atoms in said substituent group asdetermined by GC in accordance with ASTM D2887; (iii) the poly(propylenyl) substituentgroup of less than or equal to 25 mass % of said one or more 1-poly(propylenyl)benzenes hasgreater than or equal to 30 total carbon atoms in said substituent group as determined by GC inaccordance with ASTM D2887; (v) the poly(propylenyl) substituent group comprises apoly(propylenyl) substituent group having 21, 24 and / or 27 total carbon atoms; and, (v) the PF2019M006 / FF38poly(propylenyl) substituent group comprises poly(propylenyl) substituents having a branchedchain structure.(iii) Synthesis of 4-poly(propylenyl)benzene sulphonic acidThe title compound is synthesised from the 1-poly(propylenyl)benzene product of step (ii)using the same procedure to form 4-poly(butylenyl)benzene sulphonic acid as described in step(iii) for Component A.The isolated 4-poly(propylenyl)benzene sulphonic acid has: (i) a Mn of between 450 to 550daltons; (ii) the poly(propylenyl) substituent group of greater than or equal to 60 mass % ofsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s) has greater than or equal to 21total carbon atoms in said substituent group as determined by GC in accordance with ASTMD2887; (iii) the poly(propylenyl) substituent group of from 65 to 90 mass % of said one ormore 4-poly(propylenyl)benzene sulphonic acid(s) has from 21 to 27 total carbon atoms in saidsubstituent group as determined by GC in accordance with ASTM D2887; (iv) thepoly(propylenyl) substituent group of less than or equal to 25 mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) has greater than or equal to 30 total carbon atomsin said substituent group as determined by GC in accordance with ASTM D2887; (v) thepoly(propylenyl) substituent group comprises a poly(propylenyl) substituent group having 21,24 and / or 27 total carbon atoms; and, (vi) the poly(propylenyl) substituent group comprisespoly(propylenyl) substituents having a branched chain structureSuitable Additives B are available from Infineum UK Ltd, for example, comprising 85 mass %a.i. of 4-poly(propylenyl)benzene sulphonic acids.Crude Oil BlendA blend of a Columbian heavy crude oil (asphaltene content 10 wt %) and a shale oil in aweight to weight ratio of 1:1.Crude Oil Asphaltene Stability TestThe test is performed using an Automated Stability Analyser from Rofa France in accordancewith ASTM D7157. The test demonstrates the ability of a crude oil to resist destabilisation PF2019M006 / FF39upon the addition of heptane. Results are recorded as ‘S’ values, the intrinsic stability of the oilwith respect to precipitation of asphaltenes therefrom. Higher ‘S’ values indicate that the oilhas a higher capacity to solvate and / or disperse asphaltenes, and the oil is more stable in respectof asphaltene flocculation and / or precipitation. The results herein are reported as a “Relative‘S’ Value” with respect to the crude oil blend not including Additive A and / or Additive B.RESULTSAdditive(s)(treat rate; ppm a.i.)Ratio of A:B(treat rate; ppm a.i.)Relative S-ValueNone - 1.00A (2075 ppm) - 1.19A (830 ppm) - 1.14B (850 ppm) - 1.05A + B (835 ppm) 3:1 1.14The results show that, when a single additive is used Additive A gave the best results (14%improvement over the control at a treat rate of 830 ppm by mass a.i.). Additive B also providedan improvement, albeit not as significant as Additive A, over the control (5 % improvement ata treat rate of 850 ppm by mass a.i.). Increasing the treat rate of Additive A from 830 ppm bymass a.i. to 2075 ppm by mass a.i., provided a further marginal improvement in performance.

Claims

CLAIMS1. A method for enhancing the capacity of a crude oil to solvate and / or disperse asphaltenesin said crude oil, the method comprising adding an effective minor amount of Additive A orAdditive B, or an effective minor amount of a combination of Additive A and Additive B, tothe crude oil; wherein:(i) Additive A, when present, is present in an effective minor amount of from 1 to 10000ppm by mass, based on the total mass of the crude oil, and Additive A comprises one ormore 4-poly(butylenyl)benzene sulphonic acid(s), wherein the poly(butylenyl)substituent group of greater than 50 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the total mass of allsaid one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than or equalto 32 total carbon atoms in said substituent group, as determined by GC; and,(ii) Additive B, when present, is present in an effective minor amount of from 1 to 10000ppm by mass, based on the total mass of the crude oil, and Additive B comprises one ormore 4-poly(propylenyl)benzene sulphonic acids, wherein the poly(propylenyl)poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the total mass of allsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equalto 21 total carbon atoms in said substituent group, as determined by GC.

2. The use, of an effective minor amount of Additive A or Additive B, or an effectiveminor amount of a combination of Additive A and Additive B, as an additive, or a combinationof additives A and B, in a crude oil to enhance the capacity of a crude oil to solvate and / ordisperse asphaltenes in said crude oil, wherein: Additive A comprises one or more 4-poly(butylenyl)benzene sulphonic acid(s), wherein the poly(butylenyl) substituent group ofgreater than 50 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) ofAdditive A, based on the total mass of all said one or more 4-poly(butylenyl)benzene sulphonicacid(s), has greater than or equal to 32 total carbon atoms in said substituent group, asdetermined by GC; and, Additive B comprises one or more 4-poly(propylenyl)benzenesulphonic acids, wherein the poly(propylenyl) substituent group of greater than 50 mass % ofsaid one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the total PF2019M006 / FF41mass of all said one or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than orequal to 21 total carbon atoms in said substituent group, as determined by GC.

3. The use, of an effective minor amount of Additive A or Additive B, or an effectiveof additives A and B, in a crude oil to enhance the solubility and / or dispersibility of asphaltenesin said crude oil, wherein: Additive A comprises one or more 4-poly(butylenyl)benzenesulphonic acid(s), wherein the poly(butylenyl) substituent group of greater than 50 mass % ofsaid one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the totalmass of all said one or more 4-poly(butylenyl)benzene sulphonic acid(s), has greater than orequal to 32 total carbon atoms in said substituent group, as determined by GC; and, AdditiveB comprises one or more 4-poly(propylenyl)benzene sulphonic acids, wherein thepoly(propylenyl) substituent group of greater than 50 mass % of said one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, based on the total mass of all saidone or more 4-poly(propylenyl)benzene sulphonic acid(s), has greater than or equal to 21 total4. The method or use as claimed in any one of the preceding claims, wherein the crude oilhas an asphaltene content.

5. The method or use as claimed in any one of the preceding claims, wherein the crude oilcomprises a single type of crude oil or a crude oil blend comprising two or more different typesof crude oil.

6. The method or use as claimed in any one of the preceding claims, wherein Additive Aor Additive B, or a combination of Additive A and Additive B, is each independently added tothe crude oil before said crude oil arrives at a petroleum refinery.

7. The method or use as claimed in any one of the preceding claims, wherein Additive Athe crude oil at one or more crude oil production and / or processing stages, preferably beforethe crude oil arrives at a petroleum refinery, selected from: (i) to the crude oil residing in asubterranean crude oil reservoir; (ii) to the crude oil during storage of the crude oil; (iii) to the42crude oil during transportation of the crude oil; (iv) to the crude oil before or during a blendingprocess of the crude oil.

8. The method or use as claimed in any one of the preceding claims, wherein Additive Ais added to the crude oil.

9. The method or use as claimed in any one of claims 1 to 7, wherein Additive A andAdditive B are used in combination.

10. The method or use as claimed in claim 9, wherein the mass:mass ratio of Additive A toAdditive B is in the range of 10:1 to 1:10, preferably 3:1 to 1:3, more preferably 3:1 to 1:1.

11. The method or use as claimed in claim 9 or 10, wherein the combined treat rate ofAdditive A and Additive B is from 2 to 10000, preferably 2 to 1000 ppm by mass, based onthe total mass of the crude oil.

12. The method or use as claimed in any one of the preceding claims, wherein thepoly(butylenyl) substituent group of less than 30 mass % of said one or more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, based on the total mass of all said oneor more 4-poly(butylenyl)benzene sulphonic acid(s) of Additive A, has greater than or equalto 60 total carbon atoms in said substituent group, as determined by GC.

13. The method or use as claimed in any one of the preceding claims, wherein thepoly(butylenyl) substituent group of said one or more 4-poly(butylenyl)benzene sulphonicacid(s) of Additive A is derived from the polymerization of but-1-ene and has a branched chainstructure.

15. The method or use as claimed in any one of the preceding claims, wherein Additive A hasa number average molecular weight (Mn) of from 550 to 800 daltons, preferably a numberaverage molecular weight (Mn) of from 550 to 800 daltons and a polydispersity index of from1.1 to 1.5.4316. The method or use as claimed in any one of the preceding claims, wherein thepoly(propylenyl) substituent group of less than or equal to 25 mass % of said one or more 4-one or more 4-poly(propylenyl)benzene sulphonic acid(s) of Additive B, has greater than 3017. The method or use as claimed in any one of the preceding claims, wherein thepoly(propylenyl) substituent group of said one or more 4-poly(propylenyl)benzene sulphonicacid(s) of Additive B has a number average molecular weight (Mn) of from 400 to 600 daltons.

18. The method or use as claimed in any one of the preceding claims, wherein theacids of Additive B is derived from the polymerization of prop-1-ene and has a branched chain19. The method or use as claimed in any one of the preceding claims, wherein the crude oil isat ambient temperature.

20. The method or use as claimed in any one of the preceding claims, wherein Additive Aor Additive B, or a combination of Additive A and Additive B, are used with or as emulsionbreakers(for demulsification), corrosion inhibitors, hydrate inhibitors, scale inhibitors, flowimprovers, wax deposition inhibitors (or paraffin suppressants), pour-point depressants,viscosity improvers and / or other additives.