Biodegradable hydrocarbon fluids as drilling fluids and their use

Abstract

The invention is a fluid having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C, said fluid comprising : - from 70% to 95% by weight of isoparaffins, and - from 30 to 600 ppm by weight of aromatics, based on the total weight of the fluid, said fluid comprising a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms. The invention also relates to the use of the fluid for improving lubricity of drilling formulations.

Description

[0001] BIODEGRADABLE HYDROCARBON FLUIDS AS DRILLING FLUIDS AND THEIR USE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a biodegradable fluid improving the lubricity of oil-based formulations, such as oil-based muds whether during drilling or during formation fracturing or completion operation.

[0004] The invention also relates to the use of this biodegradable composition in an oil-based formulation, such as an oil-based mud as an additive among other functional additives suitable for the application envisaged for said mud whether in drilling or in fracturing or completion operation.

[0005] The fluids as used in the invention, hereinafter referred to as being improved fluids, have a narrow boiling range and a very low aromatic content, and exhibit valuable properties making them especially suited for their use as drilling fluids in drilling formulations, especially for their lubricating properties. Plus, the additive-treated oil-based mud obtained after adding all its components is particularly suitable for offshore and onshore drilling operations and completion operation.

[0006] BACKGROUND ART

[0007] Oil-based compositions can find uses in drilling or in fracturing or in completion operation. Oilbased muds are particularly used in drilling applications.

[0008] Certain sites, such as large civil engineering projects, use large quantities of fluids containing additives improving their lubricant properties and / or resistance to friction which aid the proper operation of the tools used with these fluids, in particular for machining, piercing and / or drilling, where there are major problems with friction. However, these fluids used in large quantities may be released in the form of rocky spoil after use, which means that they must not expose the environment to any danger. Often this rocky spoil must be retreated after use. Therefore, on of the objectives is to provide fluids that are readily biodegradable and can be released into the environment. This applies in particular to drilling fluids and muds, both offshore and onshore.

[0009] It is known that drilling is of prime importance in petroleum exploitation and that drilling is done deeper in the ground. The drilling technology is constantly evolving, whether onshore or offshore, especially deep offshore, but also, more recently, in horizontal or deflected drilling, where, by successive inclinations of one or two degrees, the trajectory of the well becomes curved, which makes it possible to reach horizontal deposits at least more than a kilometre or even more than ten kilometres from the wellhead.

[0010] The frictional forces that are exerted are therefore becoming greater and greater, justifying the increased importance of the lubricant properties of the drilling fluid and of its effect on resistance to friction at the level of the drilling tools.

[0011] As is well known, the drilling technique uses a drill bit fixed on the end of drill pipes, which, when driven in rotation, bores the well by grinding the rocks. As drilling progresses, drill bits of smaller and smaller diameter are used, and at each step the well is consolidated with a steel tube called “casing”, which is lowered inside the hole, and then fixed with cement.

[0012] During drilling, a drilling fluid is circulated, with injection through the nozzle of drill bit and expulsion from the latter into the contact zone with the rock, and is then brought back up to the top of the well through the annular space separating the drill pipes from the “casing”.

[0013] This fluid generally performs the following main functions: cooling the drill bit, suspending the rock cuttings and carrying them to surface smoothly, controlling the well pressure enhancing the Rate of Penetration (ROP) by self lubricating the wellbore reducing the metal / metal frictional forces, between the casing and the drill pipes, and metal / rock frictional forces, both at the level of the drill bit and in the annular zone, since the fluid comes up laden with particles of ground rock, called “cuttings” in the art, discharging the rock debris to the exterior, creating a pressure on the walls of the hole, to prevent their collapse, and balancing the pressures between the bottom of the well and the surface, in order to maintain control of the well and prevent a blowout.

[0014] In the case of deep-water offshore drilling, the water temperatures encountered, close to 4 to 5°C, require good control of the viscosity of the drilling fluids at these low temperatures.

[0015] Various types of drilling fluids or muds have been used in the past, such as water-based fluids, containing water and additives for adjusting their density and their rheological properties, oil-based fluids, and emulsions of the water-in-oil type or inverted emulsions, of the oil-in-water type, as described in particular in U.S. Pat. No. 2,816,073.

[0016] In water-based muds (WBMs), the drilling fluid is water; the water-based muds are generally reserved for applications that are not very technical and for very shallow onshore or offshore drilling (a few metres).

[0017] As in the case of fluids containing a high proportion of water, various problems arise such as excessive acidity or basicity of these muds, which can give rise to blocking of the tools, adjustment of the density and viscosity but also problems of friction at the level of the drilling tool and tool-rock contacts. This last-mentioned point raises the problem of the lubricating capacity of a water-based mud and improvement of its lubricity with additives called lubricity additives and / or anti-wear additives and / or also anti-friction additives.

[0018] As for the oil based fluids, they generally come from petroleum based crude oil which is a nonrenewable resource. Renewable fluids have also been described for their use in oil-based drilling formulations but they may have a carbon footprint relatively high because of their manufacturing process. There also remains a need for a drilling fluid of biologic origin and not fossil, having a reduced carbon footprint and having improved lubricating properties. An aim of the invention is to implement the sustainability into the drilling fluid operations, specifically in the oil-based drilling fluids.

[0019] Yet another aim of the invention is to remedy to the unavailability of drilling fluid oil in the carbon capture, utilization and storage (CCUS) drilling application.

[0020] SUMMARY OF THE INVENTION

[0021] The invention relates to a fluid having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C, said fluid comprising : from 70% to 95% by weight of isoparaffins, and from 30 to 600 ppm by weight of aromatics, based on the total weight of the fluid, said fluid comprising a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms.

[0022] According to an embodiment, the fluid has a boiling range from 5°C to 80°C, preferably from 10°C to 60°C, more preferably from 20°C to 40°C, and / or a kinematic viscosity at 40°C from 1 to 4 mm2 / s, preferably from 1 .1 to 3.0 mm2 / s, more preferably from 1 .2 to 2.2 mm2 / s, and / or a flash point of at least 75°C, preferably at least 80°C, and / or a pour point lower than -40°C, preferably lower than -50°C, and / or a flash point lower than 110°C, and / or an aniline point of at least 80°C, and / or a density at 15°C less than 780 kg / m3, more preferably less than 765 kg / m3, and / or a biodegradability at 28 days of at least 60%, as measured according to the OECD 301 B standard.

[0023] According to an embodiment, the fluid comprises: from 75% to 95% by weight of isoparaffins, preferably from 80% to 95%wt of isoparaffins, more preferably from 85% to 90%wt of isoparaffins, from 30 to 300 ppm of aromatics, even more preferably from 30 to 100 ppm of aromatics, for example from 30 to 80 ppm of aromatics, from 1 to 30%wt of n-paraffins, preferably from 2 to 20%wt of n-paraffins, more preferably from 3 to 15%wt of n-paraffins, naphthens in an amount of less than 5%wt of naphthens, preferably in an amount from

[0024] 0. 1 to 3%wt of naphthens, more preferably from 0. 5 to 2%wt of naphthens, based on the total weight of the fluid. According to an embodiment, the fluid comprises an isoparaffins to n-paraffins mass ratio of less than 8.5:1 , even more preferably ranging from 5:1 to 8:1 .

[0025] According to a particularly preferred embodiment, the fluid comprises:

[0026] - from 65 to 85%wt of isoparaffins having from 12 to 14 carbon atoms, preferably from 10 to 40%wt of isoparaffins having 12 carbon atoms, and 10 to 40%wt of isoparaffins having 13 carbon atoms and 10 to 40%wt of isoparaffins having 14 carbon atoms,

[0027] - less than 5%wt of isoparaffins having 1 1 carbon atoms or less than 11 carbon atoms,

[0028] - from 5 to 20%wt of n-paraffins having from 12 to 14 carbon atoms,

[0029] - less than 2%wt of n-paraffins having 1 1 carbon atoms or less than 11 carbon atoms,

[0030] - from 2 to 9%wt of isoparaffins having 15 carbon atoms or more than 15 carbon atoms, based on the total weight of the fluid.

[0031] According to a preferred embodiment, the fluid has a flash point lower than 110°C, preferably ranging from 75°C to less than 110°C, more preferably from 80°C to less than 110°C.

[0032] According to an embodiment, the fluid has a flash point ranging from 80°C to 100°C.

[0033] The flash point can be measured according to ASTM D93 standard.

[0034] The invention is also directed to a drilling formulation comprising: the fluid according to the invention, and at least one additive, preferably the at least one additive is chosen among an emulsifier, an emulsion stabilizer, a salt, a viscosifier, a suspending agent, a high temperature fluid loss additive, a wetting agent, a rheology modifier, a weighing agent, water, and mixtures thereof.

[0035] Preferably, the drilling formulation according to the invention comprises from 1 to 40% by weight of the fluid, preferably from 5 to 30% by weight of the fluid.

[0036] Preferably, the drilling formulation according to the invention comprises

[0037] - from 1 to 40% by weight of the fluid of the invention, preferably from 5 to 30% by weight of the fluid of the invention,

[0038] - from 40 to 95% by weight of weighting agent(s), preferably from 50 to 90% by weight of weighting agent(s), the weighting agents being preferably barite,

[0039] - from 1 to 30% by weight of water, preferably from 2 to 20% by weight, of water, being noted that the volumic ratio fluid of the invention / water is preferably higher than 1 ,5, more preferably higher than 2,0,

[0040] - from 0,1 to 15% by weight of salt(s), preferably from 0,5 to 10% by weight of salt(s), at least one salt being preferably calcium chloride,

[0041] - from 0,5 to 15% by weight of emulsifier(s), preferably from 1 to 10% by weight of emulisifier(s), based on the total weight of the drilling formulation. The invention also relates to the use of the fluid according to the invention for improving lubricity of drilling formulations. Preferably, the drilling formulations involved in the use of the invention are as defined in relation to the drilling formulation according to the invention.

[0042] The invention is also directed to a process for preparing the fluid according to the invention, the process comprising the steps of:

[0043] - hydrodeoxygenating and hydroisomerizing a used biomass, preferably a used cooking oil, in order to obtain a hydrodeoxygenated and hydroisomerized used cooking oil,

[0044] - catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used cooking oil preferably at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr1and an hydrogen treat rate up to 200 Nm3 / ton of feed.

[0045] Preferably, the used biomass is used cooking oil and the used cooking oil is preferably selected from used vegetable oils, used animal fats, used fish oils, and mixtures thereof, preferably from used vegetable oils, preferably the used cooking oil is chosen among rapeseed oil, canola oil, colza oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linenseed oil, mustard oil, palm oil, arachis oil, castor oil, coconut oil, animal fats such as suet, tallow, blubber, recycled alimentary fats and a mixture threof.

[0046] According to an embodiment, the process according to the invention comprises the following steps: i) hydrodeoxygenating (HDO) and hydroisomerizing (ISO) a used cooking oil in order to obtain a hydrodeoxygenated and hydroisomerized used cooking oil comprising from 70 to 95%wt of isoparaffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, said hydrodeoxygenated and hydroisomerized used cooking oil preferably comprising from 1 to 30%wt of n-paraffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, ii) catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used cooking oil at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr1and an hydrogen treat rate up to 200 Nm3 / ton of feed (the feed being the hydrodeoxygenated and hydroisomerized used cooking oil) in order to reduce the aromatic content of the hydrodeoxygenated and hydroisomerized used cooking oil in such a manner that the aromatic content ranges from 30 to 600 ppm, and a hydrogenation step performed between step i) and step ii) and / or after step ii) in order to obtain a cut having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C.

[0047] The present invention allows to reduce the carbon footprint and introduce a sustainable base oil from a renewable resource, compared to fluids from fossil origin. The present invention also allows to provide a bio-sourced fluid derived from non-fossil oils acting as a base oil for the oil-based drilling application, the bio-sourced fluid exhibiting a low kinematic viscosity and a high flash point for improved drilling performances, excellent compatibility with the drilling fluid additives.

[0048] The present invention thus allows to provide similar or even better performances than existing petroleum-based aromatic oils for the same application.

[0049] The fluid according to the invention allows to reduce the overall fluid loss and drilling duration while being environmental friendly. It can be used in high temperature and high pressure conditions (HTHP) along with on-shore and off-shore conditions, especially for deep water application.

[0050] The fluid according to the invention allows to provide a drilling formulation having an improved pumpability.

[0051] The fluid according to the invention shows a very good gel strength both 10 second and 10 minutes. In particular, the fluid of the invention shows a gel strength 10-second of at least 4.8 lb / 100ft2 at 145°C and at 99MPa and / or a gel strength 10-minutes of at least 3.7 lb / 100ft2 at 145°C and at 99MPa.

[0052] The fluid according to the invention shows a very good plastic viscosity. In particular, the fluid of the invention shows a plastic viscosity of at least 4.7 cP at 175°C and at 99MPa.

[0053] The fluid according to the invention shows a very good yield point. In particular, the fluid of the invention shows a yield point of at least 0.8 lb / 100ft2 at 50°C and at 1 .4MPa.

[0054] The improved fluids of the invention are useful as drilling fluids for drilling formulations, especially where the drilling formulations comprise the improved fluid prepared by the process as described below as a continuous oil phase. The drilling formulation of the invention can have a typical composition, and can comprise the improved fluid, brine, emulsifier, lime, a viscosifier and a densifier. A preferred densifier is barite. The respective proportions are easily determined by the man skilled in the art of drilling fluids. Typically the improved fluids are used as about the same amounts as known fluids.

[0055] The drilling formulations of the invention exhibits improved lubricity, which is beneficial in oil- based-muds.

[0056] The drilling formulations can be used for offshore or on-shore applications.

[0057] The improved fluids exhibit improved properties such a low pour point, a high flash point and at the same time an appropriate viscosity.

[0058] DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0059] A first object of the present invention is a fluid having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C, said fluid comprising : from 70% to 95% by weight of isoparaffins, and from 30 to 600 ppm by weight of aromatics, based on the total weight of the fluid, said fluid comprising a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms.

[0060] The fluid of the invention comprises from 70% to 95% by weight of isoparaffins, preferably from 80% to 95%wt of isoparaffins, more preferably from 85% to 90%wt of isoparaffins, based on the total weight of the fluid.

[0061] The fluid of the invention comprises from 30 to 600 ppm by weight of aromatics, preferably from 30 to 500 ppm by weight of aromatics, more preferably from 30 to 300 ppm by weight of aromatics, even more preferably from 30 to 100 ppm by weight of aromatics, for example from 30 to 80 ppm by weight of aromatics.

[0062] Preferably, the fluid of the invention comprises from 1 to 30%wt of n-paraffins, preferably from

[0063] 2 to 20%wt of n-paraffins, more preferably from 3 to 15%wt of n-paraffins, based on the total weight of the fluid.

[0064] Preferably, the fluid of the invention comprises naphthens, preferably in an amount of less than 5%wt of naphthens, preferably in an amount from 0,01 to 2%wt of n-paraffins, more preferably from 0,05 to 1 %wt of n-paraffins, based on the total weight of the fluid.

[0065] According to a particular embodiment, the fluid of the invention comprises:

[0066] - from 70% to 95% by weight of isoparaffins, preferably from 80% to 95%wt of isoparaffins, more preferably from 85% to 90%wt of isoparaffins,

[0067] - from 30 to 300 ppm of aromatics, even more preferably from 30 to 100 ppm of aromatics, for example from 30 to 80 ppm of aromatics,

[0068] - from 1 to 30%wt of n-paraffins, preferably from 2 to 20%wt of n-paraffins, more preferably from

[0069] 3 to 15%wt of n-paraffins,

[0070] - naphthens in an amount of less than 5%wt, preferably in an amount from 0.1 to 3%wt, more preferably from 0.5 to 2%wt, based on the total weight of the fluid.

[0071] According to a particular embodiment, the fluid of the invention comprises:

[0072] - from 70% to 95% by weight of isoparaffins, preferably from 80% to 95%wt of isoparaffins, more preferably from 85% to 90%wt of isoparaffins,

[0073] - from 30 to 300 ppm of aromatics, even more preferably from 30 to 100 ppm of aromatics, for example from 30 to 80 ppm of aromatics,

[0074] - from 1 to 30%wt of n-paraffins, preferably from 2 to 20%wt of n-paraffins, more preferably from 3 to 15%wt of n-paraffins,

[0075] - naphthens in an amount of less than 5%wt, preferably in an amount from 0.1 to 3%wt, more preferably from 0.5 to 2%wt, based on the total weight of the fluid, said fluid having a flash point of less than 1 10°C, preferably from 80°C to 100°C. The content of isoparaffins, n-paraffins and naphthens can be determined according to well known methods for the skilled person, for example by gas chromatography.

[0076] The content of aromatics can be determined according to well known methods for the skilled person, for example UV spectroscopy.

[0077] The fluid of the invention has an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C.

[0078] The boiling point of the fluid can be measured according to ASTM D86 standard.

[0079] According to a preferred embodiment, the fluid has an initial boiling point in the range of from 180°C to 230°C and a final boiling point in the range of from 240°C to 280°C.

[0080] According to a preferred embodiment, the fluid has a boiling range from 5°C to 80°C, preferably from 10°C to 60°C, more preferably from 20°C to 40°C.

[0081] As understood by the skilled person, a boiling range from 5°C to 80°C means that the difference between the final boiling point and the initial boiling point is between 5°C and 80°C.

[0082] According to a particularly preferred embodiment, the fluid has an initial boiling point in the range of from 200°C to 230°C and a final boiling point in the range of from 240°C to 280°C, and the fluid has a boiling range from 20 to 40°C.

[0083] According to an embodiment, the fluid consists of a fraction having an initial boiling point of at least 200°C and a final boiling point of less than 260°C, the fraction preferably having a boiling range from 20 to 40°C.

[0084] According to a preferred embodiment, the compounds having from 12 to 14 carbon atoms represent from 50% to 90% by weight, of the total weight of the fluid.

[0085] According to a preferred embodiment, the fluid of the invention comprises:

[0086] - from 65 to 85%wt of isoparaffins having from 12 to 14 carbon atoms, preferably from 10 to 40%wt of isoparaffins having 12 carbon atoms, and 10 to 40%wt of isoparaffins having 13 carbon atoms and 10 to 40%wt of isoparaffins having 14 carbon atoms,

[0087] - less than 5%wt of isoparaffins having 11 carbon atoms or less than 11 carbon atoms, preferably from 0.1 to 5%wt of isoparaffins having 1 1 carbon atoms or less than 11 carbon atoms,

[0088] - from 5 to 20%wt of n-paraffins having from 12 to 14 carbon atoms, preferably from 1 to 9%wt of n-paraffins havign 12 carbon atoms, and 1 to 9%wt of n-paraffins having 13 carbon atoms and 1 to 9%wt of n-paraffins having 14 carbon atoms,

[0089] - less than 2%wt of n-paraffins having 11 carbon atoms or less than 11 carbon atoms, preferably from 0.1 to 2%wt of n-paraffins having 11 carbon atoms or less than 1 1 carbon atoms, from 2 to 9%wt of isoparaffins having 15 carbon atoms or more than 15 carbon atoms, preferably from 3 to 9%wt of isoparaffins having 15 carbon atoms or more than 15 carbon atoms, based on the total weight of the fluid.

[0090] According to an embodiment, the fluid has a kinematic viscosity at 40°C from 1 to 4 mm2 / s, preferably from 1 .1 to 3.0 mm2 / s, more preferably from 1 .2 to 2.2 mm2 / s.

[0091] The kinematic viscosity may be measured according to ASTM D445 standard.

[0092] According to an embodiment, the fluid has a flash point of at least 75°C, preferably at least 80°C, more preferably from 80°C to 110°C, even more preferably from 80°C to 100°C.

[0093] The flash point can be measured according to ASTM D93 standard.

[0094] According to a particular embodiment, the fluid of the invention has a flash point from 80°C to 110°C and a viscosity ranging from 1 to 4 mm2 / s and the fluid comprises:

[0095] - from 85% to 90%wt of isoparaffins,

[0096] - from 30 to 300 ppm of aromatics,

[0097] - from 3 to 15%wt of n-paraffins,

[0098] - from 0.05 to 1 %wt of naphthens, based on the total weight of the fluid.

[0099] According to an embodiment, the fluid has a pour point of less than -40°C, preferably less than -50°C.

[0100] The pour point can be measured according to ASTM D97 standard.

[0101] According to an embodiment, the fluid has an aniline point of at least 80°C.

[0102] The aniline point can be measured according to ASTM D611 standard.

[0103] According to an embodiment, the fluid has a density at 15°C inferior or equal to 780 kg / m3, more preferably inferior or equal to 765 kg / m3.

[0104] The density at 15°C can be measured according to ASTM D4052 standard.

[0105] According to a particular embodiment, the fluid of the invention has:

[0106] - a kinematic viscosity at 40°C from 1.1 to 3.0 mm2 / s, more preferably from 1.2 to 2.2 mm2 / s, and

[0107] - a flash point ranging from 80°C to 1 10°C, more preferably from 80°C to 100°C. Thus, according to an embodiment, the fluid of the invention has an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C, said fluid comprising: from 70% to 95% by weight of isoparaffins, and from 30 to 600 ppm by weight of aromatics, based on the total weight of the fluid, said fluid comprising a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms, said fluid having a flash point ranging from 80°C to 1 10°C and a kinematic viscosity at 40°C from 1 .1 to 3.0 mm2 / s.

[0108] The fluid of the invention comprises a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms. This content is advantageously higher, in particular equal to or higher than 98% and advantageously it is 100 %.

[0109] The term « biocarbon» indicates that the carbon is of natural origin and is derived from a biomaterial as indicated below. Bio-carbon content and biomaterial content are expressions indicating the same value. A renewable material or biomaterial is an organic material in which the carbon is derived from recently fixed CO2 (on human scale) via photosynthesis with the atmosphere. A biomaterial (Carbon 100 % of natural origin) has a14C / 12C isotopic ratio greater than 10-12, whilst a fossil material has a zero ratio. Isotopic14C is formed in the atmosphere and is therefore integrated via photosynthesis on a time scale of no more than a few tens of years. The half-life of14C is 5730 years. As a result, materials derived from photosynthesis, namely plants in general, necessarily have a maximum content of isotope14C.

[0110] In one embodiment, the14C / 12C isotopic ratio of the fluid of the invention is between 1.15 x 10-12and 1.2 x 1012.

[0111] Determination of the content of biomaterial or bio-carbon can be given in accordance with standards ASTM D 6866-12, method B (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04). Standard ASTM D 6866 concerns « Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis », whilst standard ASTM D 7026 concerns « Sampling and Reporting of Results for Determination of Biobased Content of Materials via Carbon Isotope Analysis ». The second standard mentions the first in the first paragraph thereof.

[0112] The first standard describes a test to measure the14C / 12C ratio of a sample and comparison with the14C / 12C ratio of a reference sample of 100 % renewable origin, to give a relative percentage of C of renewable origin in the sample. The standard is based on the same concept as14C dating, but without applying dating equations. The ratio thus calculated is indicated as «pMC» (percent Modern Carbon). If the material to be analysed is a mixture of biomaterials and fossil materials (without radioactive isotope), the pMC value obtained is directly correlated with the quantity of biomaterial contained in the sample. The reference value used for14C dating is a value dating from the 1950s. The year 1950 was chosen on account of the existence of nuclear testing in the atmosphere which sent large amounts of isotopes into the atmosphere after this date. The 1950 reference corresponds to a pMC value of 100. Having regard to thermonuclear tests, the current value to be retained is about 107.5 (which corresponds to a correction factor of 0.93). The radiocarbon signature of a plant today is therefore 107.5. A signature of 54 pMC and 99 pMC therefore corresponds to a quantity of biomaterial in the sample of 50 % and 93 % respectively.

[0113] Typically, the fluid of the invention has a biodegradability at 28 days of at least 60 %, preferably at least 70 %, more preferably at least 75 % and advantageously at least 80 %, the biodegradability being preferably measured according to OECD 301 B method.

[0114] When the biodegradability at 28 days is of at least 60%, the fluid can be named “readily biodegradable”.

[0115] Biodegradation of an organic chemical product refers to reduction of the complexity of the chemical compounds through the metabolic activity of microorganisms.

[0116] The OECD 301 B method is based on the measurement of the evolution of the content of CO2 in the suspension of the sample, according to the following principle:

[0117] A measured volume of a medium, containing a known concentration of test substance (10-20 mg / ) as the sole nominal carbon source, is aerated in the dark or under diffused light, by passing carbon dioxide-free air at a controlled flow rate. Degradation is monitored by analysing the carbon dioxide produced over a period of 28 days. The CO2 is trapped by barium or sodium hydroxide and then is determined by titration of the hydroxide in excess or as inorganic carbon. The amount of carbon dioxide produced by the test substance (corrected by the value obtained for the control containing the inoculum) is expressed as a percentage of the (theoretical) CO2Th.

[0118] The fluid of the invention is ideally derived from treatment of used materials of biological origin. The carbon of a biomaterial results from photosynthesis of plants and hence from atmospheric CO2. Degradation (by degradation it is also meant end-of-life combustion / incineration) of these materials to CO2 does not therefore contribute towards global warming since there is no increase in carbon emitted in the atmosphere. The CO2 balance of biomaterials is therefore distinctly better and contributes towards reducing the carbon footprint of the products obtained (solely the energy required for manufacture must be taken into account). On the contrary, a material of fossil origin that has degraded to CO2 will contribute towards increasing CO2 levels and hence to global warming. The fluid of the invention will therefore have a better carbon footprint than that of compounds obtained from a fossil source, as well as a better carbon footprint than that of fluids obtained from unused materials of biological origin.

[0119] Method for obtaining the fluid:

[0120] Said improved fluids can be obtained in the following manner. The fluid of the invention can be obtained starting from used biological feedstock, also called used biomass or used material of biological origin, in particular from used cooking oil(s).

[0121] The used cooking oil can be selected from used vegetable oils, used animal fats, used fish oils and mixtures thereof.

[0122] Preferably, the used cooking oil is selected from used vegetable oil. Among vegetable oils, mention may be made of tallow oil, colza oil, sunflower oil, soya oil, flax oil, olive oil, palm oil, castor oil, wood oil, corn oil, squash oil, rapeseed oil, soybean oil, jojoba oil, sesame oil, walnut oil, hazelnut oil, almond oil, shea oil, macadamia oil, cotton oil, alfalfa oil, rye oil, safflower oil, peanut oil, coconut oil and copra oil, and mixtures thereof. Preferably, the vegetable oil is selected from rapeseed oil, soybean oil, sunflower oil, palm oil, coconut oil, peanut oil, castor oil, and mixtures thereof.

[0123] More specifically, the fluid of the invention can be obtained by a process comprising the following steps: hydrodeoxygenating (HDO) and hydroisomerizing (ISO) a used biomass, preferably a used cooking oil, in order to obtain a hydrodeoxygenated and hydroisomerized used cooking oil, and catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used cooking oil preferably at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr1and an hydrogen treat rate up to 200 Nm3 / ton of feed (the feed being the hydrodeoxygenated and hydroisomerized used cooking oil).

[0124] The hydrodeoxygenation step (HDO) leads to decomposition of the structures of biological esters or triglyceride constituents, to removal of oxygenated, phosphorus- and sulfur-containing compounds, and to hydrogenation of olefinic bonds. This hydrodeoxygenation step (HDO) of the used material of biological origin is followed by isomerization of the product obtained, leading to branching of the hydrocarbon chain and to improved properties of paraffin at low temperature. A fractionating step can preferably follow after the hydrodeoxygenation and isomerization steps. Advantageously, the fractions of interest are then subjected to hydrotreatment and distillation steps to obtain the desired specifications of the fluid of the invention.

[0125] This HDO / ISO process is implemented on used biological feedstock, also called used biomass or used material of biological origin, selected from the group formed by used vegetable oils, animal fats, fish oils and mixtures thereof.

[0126] At the HDO step, hydrogen and the used material of biological origin are passed over a hydrodeoxygenation catalytic bed simultaneously, in the same direction or in counter-current. At the HDO step, the pressure and temperature are respectively between 20 and 150 bar and between 200 and 500°C. Known, conventional hydrodeoxygenation catalysts are used for this step. Optionally, the used material of biological origin, before the HDO step, can be subjected to pre-hydrogenation under mild conditions to prevent secondary reactions of double bonds. The product resulting from the hydrodeoxygenation reaction is subjected to an isomerization step (ISO) at which hydrogen and said product, and optionally a mixture of n-paraffins, are passed over isomerization catalytic beds simultaneously, in the same direction or in counter current. At the ISO step, the pressure and temperature are respectively between 20 and 150 bar and between 200 and 500°C. Known, conventional isomerization catalysts are used at this step.

[0127] Additionally, secondary processes can also be applied (e.g. intermediate mixing, scavenging or the like).

[0128] The product resulting from the HDO / ISO steps can optionally be fractionated to obtain the fractions of interest.

[0129] Various HDO / ISO processes are described in the literature. Application WO 2014 / 033762 describes a process comprising a pre-hydrogenation step, a hydrodeoxygenation step (HDO) and an isomerization step conducted in counter current flow. Patent application EP 1728844 describes a method for producing hydrocarbon compounds from a mixture of compounds of vegetable and animal origin. This method comprises a pre-treatment step of the mixture to remove contaminants, e.g. alkali metal salts, followed by a hydrodeoxygenation step (HDO) an isomerization step. Patent application EP 2084245 describes a method for producing a hydrocarbon mixture, which can be used as diesel oil or in a diesel oil composition, via hydrodeoxygenation of a mixture of biological origin containing fatty acid esters optionally in a mixture with free fatty acids, for example vegetable oils such as sunflower seed oil, rapeseed oil, canola oil, palm oil or pine oil, followed by hydroisomerization on specific catalysts. Patent application EP 2368967 describes said method and the product obtained with this method.

[0130] Advantageously, the used material of biological origin contains less than 15 ppm of sulfur, preferably less than 8 ppm, more preferably less than 5 ppm and further preferably less than 1 ppm in accordance with standard EN ISO 20846. Ideally, the used material of biosourced origin used as feedstock does not contain sulfur.

[0131] Before the catalytic hydrogenation step, a pre-fractionating step can be performed. A narrower- cut fraction fed into the hydrogenation unit allows a narrow-cut fraction to be obtained on leaving the unit. The boiling points of pre-fractionated fractions are between 150 and 330°C whilst fractions which have not been pre-fractionated typically have boiling points between 100 and 360°C.

[0132] The deoxygenated, isomerized feedstock derived from the HDO / ISO process is hydrogenated. The hydrogen used in the hydrogenation unit is typically highly purified hydrogen. By highly purified hydrogen it is meant hydrogen having purity higher than 99 % for example, even if other grades could also be used.

[0133] The hydrogenation step is conducted by means of catalysts. Standard hydrogenation catalysts can either be bulk or supported, and may comprise the following metals: nickel, platinum, palladium, rhenium, rhodium, nickel tungstate, nickel-molybdenum, molybdenum, cobalt-molybdenum. The supports can be silica, alumina, silica-alumina or zeolites. One preferred catalyst is a nickel-based catalyst on an alumina support having a specific surface area which varies between 100 and 200 m2 / g of catalyst, or a bulk nickel catalyst. Conditions for hydrogenation are typically the following:

[0134] Pressure: 50 to 160 bar, preferably 80 to 150 bar and more preferably 90 to 120 bar;

[0135] Temperature: 80 to 180°C, preferably 120 to 160°C and more preferably 150 to 160°C;

[0136] Liquid Hourly space velocity (LHSV): 0.2 to 5 hr1, preferably 0.4 to 3 hr1and more preferably 0.5 to 0.8 hr-1 ;

[0137] Hydrogen treatment rate: adapted to the above-mentioned conditions and possibly reaching 200 Nm3 / tonnes of feedstock to be treated.

[0138] The temperature in the reactors is typically between 150 and 160°C with a pressure of about 100 bar, whilst the liquid hourly space velocity is about 0.6 hr1with a treatment rate adapted as a function of the quality of the feedstock to be treated and the parameters of the first hydrogenation reactor.

[0139] Hydrogenation can also take place in one or more reactors in series. The reactors may comprise one or more catalytic beds. The catalytic beds are generally fixed catalytic beds.

[0140] The hydrogenation process is preferably carried out in two or three reactors, preferably in three reactors and more preferably in three reactors in series.

[0141] The first reactor is used for scavenging of sulfur-containing compounds and hydrogenation of essentially all unsaturated compounds and up to about 90 % of aromatic compounds. The product leaving the first reactor contains substantially no sulfur-containing compound. At the second stage i.e. in the second reactor hydrogen of the aromatics is continued and up to 99 % of aromatics are thereby hydrogenated.

[0142] The third stage in the third reactor is a finishing stage allowing contents of aromatics to be obtained of 600 ppm or less, preferably 500 ppm or less, more preferably 300 ppm or less and further preferably 100 ppm or less, and ideally equal to or less than 80 ppm.

[0143] It is possible to use a reactor comprising two, three or more catalytic beds. The catalysts can be in variable amounts possibly being different or essentially the same in each reactor; for three reactors, the amounts as a function of weight can be 0.05-0.5 / 0.10-0.70 / 0.25-0.85 for example, preferably 0.07- 0.25 / 0.15-0.35 / 0.4-0.78 and more preferably 0.10-0.20 / 0.20-0.32 / 0.48-0.70.

[0144] It is also possible to use one or two hydrogenation reactors instead of three.

[0145] It is also possible that the first reactor is composed of twin reactors used alternately. This operating mode particularly allows facilitated loading and unloading of catalysts: when the first reactor comprises the catalyst that is first saturated (substantially all the sulfur is trapped on and / in the catalyst), this catalyst must be changed often.

[0146] A single reactor can also be used in which two, three or more catalytic beds are installed.

[0147] It may be necessary to insert quench boxes (to stifle the reaction) in the recycle system or between the reactors to cool the effluents from one reactor to another or from one catalytic bed to another, to control the temperatures and hydrothermal balance of each reaction. In one preferred embodiment, there are no cooling or quenching intermediates.

[0148] In one embodiment, the product resulting from the process and / or the separated gas(s) are at least partly recycled back into the feed system of the hydrogenation reactors. This dilution contributes towards maintaining the exothermicity of the reaction within controlled limits, in particular at the first stage. In addition, recycling allows heat exchange before the reaction and additionally better control over temperature.

[0149] The effluent from the hydrogenation unit chiefly contains the hydrogenated product and hydrogen. Flash separators are used to separate the effluents into a gas phase, mainly residual hydrogen, and a liquid phase mainly hydrogenated hydrocarbon fractions. This process can be carried out using three flash separators, one at high pressure, one at intermediate pressure and one at low pressure very close to atmospheric pressure.

[0150] The gaseous hydrogen collected data the top of the flash separators can be recycled back to the feed system of the hydrogenation unit, or to different stages in the hydrogenation units between the reactors.

[0151] In one embodiment, the end product is separated at atmospheric pressure. It is then fed directly into a vacuum fractionating unit. Preferably, fractionation is performed at a pressure of between 10 and 50 bar, and more preferably at about 30 bar.

[0152] Fractionation can be performed so that it is possible simultaneously to withdraw various hydrocarbon fluids from the fractionating column, and so that their boiling point is able to be predetermined.

[0153] By adapting the feedstock via the initial and final boiling points thereof, the hydrogenation reactors, separators and fractionating unit can therefore be directly connected without the need for intermediate vessels. This continuity between hydrogenation and fractionation allows optimised thermal integration associated with a reduction in the number items of equipment together with energy savings.

[0154] The fluid of the invention is advantageously a hydrocarbon fraction having an initial boiling point in the range of 180°C to 240°C, preferably 190°C to 230°C and more preferably 200°C to 220°C, and a final boiling point in the range of 240°C to 300°C, preferably 240°C to 280°C. Preferably, the difference between the final boiling point and initial boiling point is from 5°C to 80°C, preferably from 10°C to 60°C, more preferably from 20°C to 40°C. The hydrocarbon oil may comprise one or more fractions having distillation ranges lying within the above ranges.

[0155] According to an embodiment, the process for manufacturing the fluid of the invention comprises the following steps: i. hydrodeoxygenating (HDO) and hydroisomerizing (ISO) a used cooking oil in order to obtain a hydrodeoxygenated and hydroisomerized used cooking oil comprising from 70 to 95%wt of isoparaffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, said hydrodeoxygenated and hydroisomerized used cooking oil preferably comprising from 1 to 30%wt of n-paraffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, ii. catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used cooking oil at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr-1 and an hydrogen treat rate up to 200 Nm3 / ton of feed (the feed being the hydrodeoxygenated and hydroisomerized used cooking oil) in order to reduce the aromatic content of the hydrodeoxygenated and hydroisomerized used cooking oil in such a manner that the aromatic content ranges from 30 to 600 ppm, and fractioning step performed between step i) and step ii) and / or after step ii) in order to obtain a cut having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C.

[0156] Drilling formulation

[0157] The invention is also directed to a drilling formulation comprising the fluid of the invention and at least one additive.

[0158] The drilling formulation according to the invention is advantageously an oil-based drilling formulation, also named oil based-mud.

[0159] According to an embodiment, the drilling formulation comprises from 1 to 40% by weight of the fluid, preferably from 5 to 30% by weight of the fluid, based on the total weight of the drilling formulation. Preferably, the fluid of the invention is the lubricant (base oil) of the drilling formulation.

[0160] According to an embodiment, the at least one additive is chosen from an emulsifier, an emulsion stabilizer, a salt, a viscosifier, a suspending agent, a high temperature fluid loss additive, a wetting agent, a rheology modifier, a weighing agent, water, and mixtures thereof.

[0161] According to an embodiment, the drilling formulation comprises:

[0162] - from 1 to 40% by weight of the fluid of the invention, preferably from 5 to 30% by weight of the fluid of the invention,

[0163] - from 60 to 99% by weight of additives selected from an emulsifier, an emulsion stabilizer, a salt, a viscosifier, a suspending agent, a high temperature fluid loss additive, a wetting agent, a rheology modifier, a weighing agent, water, and mixtures thereof, based on the total weight of the drilling formulation.

[0164] According to an embodiment, the drilling formulation comprises:

[0165] - from 1 to 40% by weight of the fluid of the invention, preferably from 5 to 30% by weight of the fluid of the invention,

[0166] - from 40 to 95% by weight of weighting agent(s), preferably from 50 to 90% by weight of weighting agent(s), the weighting agents being preferably barite, - from 1 to 30% by weight of water, preferably from 2 to 20% by weight, of water, being noted that the volumic ratio fluid of the invention / water is preferably higher than 1 ,5, more preferably higher than 2,0,

[0167] - from 0,1 to 15% by weight of salt(s), preferably from 0,5 to 10% by weight of salt(s), at least one salt being preferably calcium chloride,

[0168] - from 0,5 to 15% by weight of emulsifier(s), preferably from 1 to 10% by weight of emulisifier(s), based on the total weight of the drilling formulation.

[0169] The present invention is also directed to the use of the fluid of the invention in an oil-based mud also called oil-based drilling formulation, preferably in order to improve the lubricity of the drilling formulation and / or to improve the high temperature performances of the drilling formulation.

[0170] The fluid can be added in an amount ranging from 1 to 40% by weight of the fluid, preferably from 5 to 30% by weight of the fluid, based on the total weight of the drilling formulation.

[0171] Preferably, the fluid of the invention is the unique base oil / lubricant of the oil-based drilling formulation.

[0172] The use of the invention consists preferably in mixing the fluid of the invention with the at least one additive, the fluid being added preferably in an amount ranging from 1 to 40% by weight, preferably from 1 to 15% by weight, based on the total weight of the drilling formulation.

[0173] According to a particular embodiment, the drilling formulation is an oil-based mud.

[0174] According to a particular embodiment, the drilling formulation obtained after the use of the invention comprises one or more of the features defined for the drilling formulation of the invention.

[0175] The present invention is also directed to a process of improving lubricity of a drilling formulation and / or to improve the high temperature performances of a drilling formulation, the process comprising a step of mixing the fluid of the invention with the at least one additive, the fluid being added preferably in an amount ranging from 1 to 40% by weight, preferably from 1 to 15% by weight, based on the total weight of the drilling formulation.

[0176] Typically, the drilling formulation recovered at the end of the process has an improved lubricity and improved high temperature performances.

[0177] According to a particular embodiment, the drilling formulation obtained at the end of the process of the invention comprises one or more of the features defined for the drilling formulation of the invention.

[0178] The following example illustrates the invention without limiting it.

[0179] EXAMPLES The invention is now described with the help of the following examples, which are not intended to limit the scope of the present invention, but are incorporated to illustrate advantages of the present invention and best mode to perform it.

[0180] Example 1 : Comparison of the physico-chemical properties of the fluid according to the invention and two comparative fluids

[0181] Three fluids were prepapred: a fluid according to the invention based on used cooking oil, a comparative 1 based on crude oil and a comparative 2 based on raw vegetable oil.

[0182] The fluid according to the invention based on used cooking oil has a lower carbon footprint than comparative fluids.

[0183] The fluid according to the invention implemented in this non-limiting example comprises about 86.96%wt of isoparaffins, about 11 .2%wt of n-paraffins, about 0.1 %wt of naphthenes and more than 50 ppm by weight of aromatics.

[0184] The following standards have been used to determine the following properties:

[0185] Density at 15°C ASTM D4052

[0186] Aniline point ASTM D611

[0187] Pour point ASTM D97

[0188] Flash point ASTM D93

[0189] Viscosity at 40°C ASTM D445

[0190] Aromatic content UV spectroscopy

[0191] Atmospheric distillation ASTM D86

[0192] TABLE 1 The data in the Table 1 shows that the fluid according to the invention has a higher flash point and a lower viscosity than the comparative fluid 1 . This confirms that the fluid according to the invention has an improved performance for drilling.

[0193] Pour point of both the fluid according to the invention and the comparative fluid 2 is quite similar which represents similar low temperature property of them.

[0194] These results show that the fluid according to the invention has very good properties, in particular the properties of the fluid of the invention are an indicator of performances that are at least identical or even better than that of comparative fluids 1 and 2.

[0195] Example 2: Preparation of oil drilling muds

[0196] Tables 2 and 3 show mud compositions in which the fluids detailed in example 1 were mixed with different additives to form a first mud composition of 13.5 ppg density and a second mud composition of 18 ppg density. The additives were mixed as per the corresponding time and mixing order shown below.

[0197] Multimixer was used to mix and formulate the fluid in line with API recommendations of 11500 ± 300 rpm without shear. Each formulation was calculated and prepared in one lab barrel (350 mL) for operational convenience. Both Before and After Hot Rolling (BHR and AHR) fluids were evaluated, and the hot rolling condition was set at 65.56°C (150 °F) for 16hrs under pressurized conditions.

[0198] While mixing the first and second muds, it was observed that the components mixed without any compatibility issues. For both muds, additives were mixed well. After hot rolling, they were stable, and no additive separation or lump formation was found.

[0199] TABLE 2

[0200] For the second mud composition, all the components were the same for the three muds except for the fluid (according to the invention, comparatives 1 and 2).

[0201] TABLE 3

[0202] Example 3: Measurement of density, electrical stability test, viscosity at different shear rate and HPHT fluid loss of the 13.5 ppg mud Table 4 shows the data of all rheological, HPHT fluid loss and electrical stability test of the 13.5 ppg mud (first mud compositions detailed in Table 2).

[0203] BHR and AHR represent the before hot rolling and after hot rolling data.

[0204] The tests were carried out at a temperature of 49°C. TABLE 4

[0205] According to the data of table 4, the viscosity of the mud formulation according to the invention is stable compared to the mud with comparative 1 before and after hot rolling. In addition, the electrical stability values prove that the mud formulation according to the invention is more stable than the mud with comparative 1. Gel strengths for 10 minutes and 10 seconds are higher for the mud formulation according to the invention compared to the mud with comparative 1 which implies better pump ability.

[0206] The fluid loss at 148.9 °C for the mud formulation according to the invention is lower than 3 mL / 30 min meaning that the high temperature properties of the mud formulation according to the invention is satisfying.

[0207] The mud with comparative 2 is showing stable viscosities before and after hot rolling as it is a heavier cut product. The electrical stability values prove that the oil-water emulsion for the mud formulation according to the invention is more stable than the mud with comparative 2 before hot rolling. Gel strengths for 10 minutes and 10 seconds are higher for the mud formulation according to the invention rather than the mud with comparative 2 which implies better pumpability.

[0208] Thus, the mud formulation according to the invention allows to obtain a good stability and an improved pumpability, as well as a reduced carbon footprint.

[0209] Example 4: High temperature high pressure rheology of the 18 ppg mud

[0210] HTHP Rheology tests were performed with the second mud composition (detailed in Table 3). Pre-decided testing conditions was used to measure the fluids properties of after hot rolled mud (at 65.6°C for 16 hours). The mud formulation containing the fluid according to the invention was compared to the mud formulations with comparatives 1 and 2 (detailed in Table 3).

[0211] The tests were conducted from at a temperature ranging from 50 to 175°C and at a pressure ranging from 1.4 MPa to 120.7 MPa for high-end viscosity (600 and 300 shear), mid or medium range viscosity (200 and 100 shear), low end viscosity (6 and 3 shear).

[0212] The plastic viscosity of the mud containing the fluid according to the invention varied from 4.7 to 11 .2 cP.

[0213] The yield point of the mud containing the fluid according to the invention varied from 0.8 to 3.8 lb / 100ft2. Gel strengths for 10 minutes and 10 seconds are in the range of 4.8 to 7.6 lb / 100ft2and 3.7 to

[0214] 7.8 lb / 100ft2respectively.

[0215] The mud formulation with the fluid according to the invention having a light cut product with mainly C12-C14 compounds has shown satisfactory properties, in particular very good high temperature performances, and it has the potential to perform far better compared to the conventional base oils for drilling application.

Claims

CLAIMS1. A fluid having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C, said fluid comprising : from 70% to 95% by weight of isoparaffins, and from 30 to 600 ppm by weight of aromatics, based on the total weight of the fluid, said fluid comprising a biocarbon content of at least 95% by weight based on the total weight of the carbon atoms.

2. The fluid according to claim 1 , having a boiling range from 5°C to 80°C, preferably from 10°C to 60°C, more preferably from 20°C to 40°C, and / or a kinematic viscosity at 40°C from 1 to 4 mm2 / s, preferably from 1.1 to 3.0 mm2 / s, more preferably from 1 .2 to 2.2 mm2 / s, and / or a flash point of at least 75°C, preferably at least 80°C, and / or a pour point lower than -40°C, preferably lower than -50°C.

3. The fluid according to claim 1 or 2, having a flash point lower than 1 10°C, preferably from 75°C to less than 110°C, more preferably from 80°C to 100°C.

4. The fluid according to claim 1 or 2, having a flash point lower than 110°C, and / or an aniline point of at least 80°C, and / or a density at 15°C less than 780 kg / m3, more preferably less than 765 kg / m3.

5. The fluid according to claims 1 to 4, comprising: from 75% to 95% by weight of isoparaffins, preferably from 80% to 95%wt of isoparaffins, more preferably from 85% to 90%wt of isoparaffins, from 30 to 300 ppm of aromatics, even more preferably from 30 to 100 ppm of aromatics, for example from 30 to 80 ppm of aromatics, from 1 to 30%wt of n-paraffins, preferably from 2 to 20%wt of n-paraffins, more preferably from 3 to 15%wt of n-paraffins, naphthens in an amount of less than 5%wt of naphthens, preferably in an amount from 0. 1 to 3%wt of naphthens, more preferably from 0. 5 to 2%wt of naphthens, based on the total weight of the fluid.

6. The fluid according to any one of the preceding claims, wherein the fluid has a biodegradability at 28 days of at least 60%, as measured according to the OECD 301 B standard.

7. The fluid according to any one of the preceding claims, comprising:- from 65 to 85%wt of isoparaffins having from 12 to 14 carbon atoms, preferably from 10 to 40%wt of isoparaffins having 12 carbon atoms, and 10 to 40%wt of isoparaffins having 13 carbon atoms and 10 to 40%wt of isoparaffins having 14 carbon atoms,- less than 5%wt of isoparaffins having 1 1 carbon atoms or less than 11 carbon atoms,- from 5 to 20%wt of n-paraffins having from 12 to 14 carbon atoms,- less than 2%wt of n-paraffins having 11 carbon atoms or less than 1 1 carbon atoms,- from 2 to 9%wt of isoparaffins having 15 carbon atoms or more than 15 carbon atoms, based on the total weight of the fluid.

8. A drilling formulation comprising: the fluid according to any one of claims 1 to 7, and at least one additive, preferably the at least one additive is chosen among an emulsifier, an emulsion stabilizer, a salt, a viscosifier, a suspending agent, a high temperature fluid loss additive, a wetting agent, a rheology modifier, a weighing agent, water, and mixtures thereof.

9. The drilling formulation according to claim 8, comprising from 1 to 40% by weight of the fluid, preferably from 5 to 30% by weight of the fluid.

10. The drilling formulation according to any one of claims 8 or 9, comprising:- from 1 to 40% by weight of the fluid, preferably from 5 to 30% by weight of the fluid,- from 40 to 95% by weight of weighting agent(s), preferably from 50 to 90% by weight of weighting agent(s), the weighting agents being preferably barite,- from 1 to 30% by weight of water, preferably from 2 to 20% by weight, of water, being noted that the volumic ratio fluid of the invention / water is preferably higher than 1 ,5, more preferably higher than 2,0,- from 0,1 to 15% by weight of salt(s), preferably from 0,5 to 10% by weight of salt(s), at least one salt being preferably calcium chloride,- from 0,5 to 15% by weight of emulsifier(s), preferably from 1 to 10% by weight of emulisifier(s), based on the total weight of the drilling formulation.

11. A use of the fluid according to any one of claims 1 to 7 for improving lubricity of drilling formulations.

12. The use according to claim 11 , wherein the drilling formulations are as defined in any one of claims 7 to 9.

13. A process for preparing the fluid according to any one of claims 1 to 7, the process comprising the steps of:- hydrodeoxygenating and hydroisomerizing a used biomass, preferably a used cooking oil, in order to obtain a hydrodeoxygenated and hydroisomerized used biomass, preferably a hydrodeoxygenated and hydroisomerized used cooking oil,- catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used biomass preferably at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr1and an hydrogen treat rate up to 200 Nm3 / ton of feed.

14. The process according to claim 13, wherein the used biomass is a used cooking oil preferably selected from used vegetable oils, used animal fats, used fish oils, and mixtures thereof, preferably from used vegetable oils, preferably the used cooking oil is chosen among rapeseed oil, canola oil, colza oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linenseed oil, mustard oil, palm oil, arachis oil, castor oil, coconut oil, animal fats such as suet, tallow, blubber, recycled alimentary fats and a mixture threof.

15. The process according to one of claims 13 or 14, comprising the following steps: i) hydrodeoxygenating (HDO) and hydroisomerizing (ISO) a used cooking oil in order to obtain a hydrodeoxygenated and hydroisomerized used cooking oil comprising from 70 to 95%wt of isoparaffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, said hydrodeoxygenated and hydroisomerized used cooking oil preferably comprising from 1 to 30%wt of n-paraffins based on the total weight of the hydrodeoxygenated and hydroisomerized used cooking oil, ii) catalytically hydrogenating the hydrodeoxygenated and hydroisomerized used cooking oil at a temperature from 80 to 180°C, at a pressure from 50 to 160 bars, a liquid hourly space velocity of 0.2 to 5 hr-1 and an hydrogen treat rate up to 200 Nm3 / ton of feed (the feed being the hydrodeoxygenated and hydroisomerized used cooking oil) in order to reduce the aromatic content of the hydrodeoxygenated and hydroisomerized used cooking oil in such a manner that the aromatic content ranges from 30 to 600 ppm, and a hydrogenation step performed between step i) and step ii) and / or after step ii) in order to obtain a cut having an initial boiling point in the range of from 150°C to 240°C and a final boiling point in the range of from 240°C to 300°C.

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