Hydrogen sulfide inhibitor for fracturing and preparation method thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a hydrogen sulfide inhibitor for fracturing and a preparation method. The preparation method comprises the following steps: carrying out phosphorus esterification reaction on sodium dihydrogen phosphate and epoxy halopropane under a high-temperature condition to generate phosphate; secondly, in a weakly alkaline environment, phosphate and triethylene diamine are subjected to quaternization reaction in a reflux state; the hydrogen sulfide inhibitor has the characteristics of simple synthesis process, small dosage and good sterilization effect, and the sterilization rate reaches 100% when the use concentration is 15mg / L.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil exploitation, and particularly relates to a hydrogen sulfide inhibitor for fracturing and a preparation method thereof. Background Art

[0002] Fracturing is a key technology for tight oil exploitation. During the fracturing process, a large amount of fracturing fluid is injected into the formation. After the implementation of the fracturing technology, it is easy for the primary or secondary hydrogen sulfide in the reservoir to migrate to the ground. The primary formation causes include crude oil associated with magma activity, and the secondary formation causes include the thermal chemical reactions of crude oil, sulfate, sulfur-containing compounds and the reduction reaction of sulfate-reducing bacteria (SRB). Hydrogen sulfide is highly toxic, which not only corrodes oilfield pipelines and equipment, but also is extremely likely to cause poisoning incidents once leaked. Effective treatment methods for hydrogen sulfide can be divided into physical methods, chemical methods and biological methods, among which the chemical method is the most commonly used for hydrogen sulfide treatment in oilfields. For biogenic hydrogen sulfide, the method of adding desulfurizing agents or bactericides can be adopted for prevention and control.

[0003] Chinese Patent CN104542584B discloses a desulfurizing bactericide and its preparation and application. This method uses 20-30% dodecyl dimethyl benzyl ammonium chloride, 5-10% poly dimethyl diallyl ammonium chloride, 1% OP emulsifier, 20-30% polymeric ferric sulfate, and the rest is water; dodecyl dimethyl benzyl ammonium chloride, poly dimethyl diallyl ammonium chloride and 1% OP emulsifier are added to water, and after complete dissolution, polymeric ferric sulfate is added, and after stirring evenly, a desulfurizing bactericide is obtained; at a reasonable dosage, it can reduce or eliminate the content of secondary hydrogen sulfide in the surface oil and water treatment system, and has certain killing and inhibitory properties on sulfate-reducing bacteria, saprophytic bacteria and iron bacteria in oilfield water. This method is applicable to the treatment of hydrogen sulfide in fracturing wells, but has a high usage concentration and large dosage, and is not economical.

[0004] Chinese Patent CN113973819B discloses a high-efficiency bactericide and its preparation method. The raw material composition of this method is: quaternary ammonium salt bactericide, dodecyl dimethyl dibenzyl ammonium stannate, dodecyl triphenyl phosphonium bromide, bis-tributyltin oxide, penetrant and water; the quaternary ammonium salt bactericide is a mixture of MHTD and poly(2-hydroxypropyl)-1,1-N-dimethylamine chloride, and the mass ratio of MHTD to poly(2-hydroxypropyl)-1,1-N-dimethylamine chloride is 1:1.2-1.3. The high-efficiency bactericide described in the present invention has good bactericidal effects on common sulfate-reducing bacteria, saprophytic bacteria and iron bacteria in reinjected water and has a long timeliness. Adding a small amount can achieve a good bactericidal effect. It has no corrosion itself and has a corrosion inhibition effect, and will not produce drug resistance after long-term use, and has good compatibility with other agents in reinjected water. The synthesis process of this bactericide is complex and its heat resistance is poor, which is not suitable for application in fracturing wells. Summary of the Invention

[0005] The present invention provides a hydrogen sulfide inhibitor for fracturing and a preparation method thereof in view of the deficiencies of the above-mentioned prior art. The hydrogen sulfide inhibitor has the characteristics of simple synthesis process, small dosage, and good bactericidal effect. When the use concentration is 15 mg / L, the bactericidal rate reaches 100%.

[0006] Therefore, in order to achieve the above object, on the one hand, the present invention discloses a hydrogen sulfide inhibitor for fracturing, and the molecular structural formula of the hydrogen sulfide inhibitor is as follows:

[0007]

[0008] On the other hand, the present invention discloses a preparation method of the above hydrogen sulfide inhibitor, and the method includes: phosphating sodium dihydrogen phosphate and epihalohydrin under high temperature conditions to generate phosphate ester; secondly, in a weakly alkaline environment, the phosphate ester and triethylenediamine undergo quaternization reaction under reflux state.

[0009] In the third aspect, the present invention discloses the application of the above hydrogen sulfide inhibitor in reservoir fracturing.

[0010] The hydrogen sulfide inhibitor for fracturing of the present invention is a Gemini bisphosphate betaine surfactant. The quaternary ammonium salt is a typical bactericidal functional group, which can form hydrogen bonds with the bases of deoxyribonucleic acid in the protein in the bacteria, adsorb on the cells of the bacteria, destroy the deoxyribonucleic acid structure of the bacteria, and make it lose the replication ability and die. The phosphate ester can insert into the lipid layer of the bacteria, change the permeability of the cell membrane, destroy the membrane structure, cause the leakage of intracellular substances, denature enzymes or proteins, inhibit the activity of enzymes or proteins, affect the cell metabolism process, and finally the bacteria die.

[0011] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0012] (1) The raw materials of the hydrogen sulfide inhibitor for fracturing of the present invention are widely sourced, the synthesis process is simple, the adaptability is strong, the temperature resistance is good, the dosage is small, and it can meet the bactericidal needs of fracturing wells at different depths;

[0013] (3) The hydrogen sulfide inhibitor for fracturing of the present invention has the advantage of high-efficiency bactericidal at low concentration. When the use concentration is 15 mg / L, the bactericidal rate reaches 100%. Specific embodiments

[0014] The endpoints and any values disclosed in this article for ranges are not limited to the precise ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0015] According to the first aspect of the present invention, a hydrogen sulfide inhibitor for fracturing is disclosed, and the molecular structural formula of the hydrogen sulfide inhibitor is as follows:

[0016]

[0017] According to the second aspect of the present invention, a preparation method of the above-mentioned hydrogen sulfide inhibitor for fracturing is provided, and the method includes: phosphating reaction of sodium dihydrogen phosphate and epihalohydrin at high temperature to generate phosphate ester; secondly, in a weakly alkaline environment, quaternization reaction of the phosphate ester and triethylenediamine occurs under reflux state.

[0018] In the present invention, preferably, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 0.8 - 1.5 mole parts and 0.4 - 0.6 mole parts respectively.

[0019] More preferably, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 1 - 1.5 mole parts and 0.45 - 0.55 mole parts respectively.

[0020] Even more preferably, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 1 - 1.2 mole parts and 0.45 - 0.50 mole parts respectively.

[0021] In the present invention, preferably, the epihalohydrin is one of epichlorohydrin, epibromohydrin and epiiodohydrin.

[0022] More preferably, the epihalohydrin is epichlorohydrin or epibromohydrin.

[0023] In the present invention, preferably, the high temperature condition is a temperature of 70 - 80 °C.

[0024] More preferably, the high temperature condition is a temperature of 70 - 75 °C.

[0025] In the present invention, preferably, the phosphating reaction time is 1 - 4 h.

[0026] More preferably, the phosphating reaction time is 2 - 3 h.

[0027] In the present invention, preferably, the weakly alkaline environment is pH 8 - 9.

[0028] In the present invention, preferably, the quaternization reaction time is 12 - 48 h.

[0029] More preferably, the quaternization reaction time is 18 - 36 h.

[0030] According to a more specific preferred embodiment, the synthesis method of the hydrogen sulfide inhibitor for fracturing specifically includes the following steps:

[0031] (1) Add sodium dihydrogen phosphate and distilled water into a four-necked flask, heat and dissolve, dropwise add epihalohydrin, and keep warm for phosphorylation reaction;

[0032] (2) Add ethanol into the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0033] (3) Add triethylenediamine into the above filtrate, adjust the pH to 8-9 with sodium hydroxide solution, and heat under reflux for quaternization reaction;

[0034] (4) Distill the solution after the above quaternization reaction under reduced pressure until dry, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor.

[0035] In the present invention, preferably, the weight ratio of the distilled water, ethanol to sodium dihydrogen phosphate is 2.5-4:5-8:1.

[0036] The reaction equation for the synthesis of the hydrogen sulfide inhibitor for fracturing in the present invention is as follows:

[0037]

[0038] The third object of the present invention discloses the application of the above hydrogen sulfide inhibitor in reservoir fracturing. There is no special requirement for the specific application, and it can be the conventional application method in the art, which will not be elaborated here.

[0039] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, without contradiction, they can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0040] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

[0041] The present invention will be further described below in conjunction with specific embodiments.

[0042] In the present invention, the devices or equipment used are all conventional devices or equipment known in the art and can be purchased.

[0043] In the following examples and comparative examples, without special description, various reagents used are all commercially available chemically pure reagents.

[0044] Example 1:

[0045] (1) Add 0.5 mol of sodium dihydrogen phosphate and 150 g of distilled water to a four-necked flask, heat to 70 °C for dissolution, add dropwise 0.4 mol of epoxyiodopropane, keep warm for 1 h, and carry out phosphorylation reaction;

[0046] (2) Add 300 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0047] (3) Add 0.2 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, heat under reflux for 12 h, and carry out quaternization reaction;

[0048] (4) Distill the solution after the above quaternization reaction under reduced pressure to dryness, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 1 .

[0049] Example 2:

[0050] (1) Add 0.5 mol of sodium dihydrogen phosphate and 240 g of distilled water to a four-necked flask, heat to 80 °C for dissolution, add dropwise 0.75 mol of epoxyiodopropane, keep warm for 4 h, and carry out phosphorylation reaction;

[0051] (2) Add 480 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0052] (3) Add 0.3 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, heat under reflux for 24 h, and carry out quaternization reaction;

[0053] (4) Distill the solution after the above quaternization reaction under reduced pressure to dryness, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 2 .

[0054] Example 3:

[0055] (1) Add 0.5 mol of sodium dihydrogen phosphate and 173 g of distilled water to a four-necked flask, heat to 75 °C for dissolution, add dropwise 0.45 mol of epichlorohydrin, keep warm for 2 h, and carry out phosphorylation reaction;

[0056] (2) Add 346 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0057] (3) Add 0.22 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, heat under reflux for 18 h, and carry out quaternization reaction;

[0058] (4) Distill the solution after the above quaternization reaction under reduced pressure to dryness, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S3 .

[0059] Example 4:

[0060] (1) Add 0.5 mol of sodium dihydrogen phosphate and 212 g of distilled water to a four-necked flask, heat to 72 °C for dissolution, add dropwise 0.5 mol of epichlorohydrin, keep warm for 2.5 h, and carry out phosphorylation reaction;

[0061] (2) Add 414 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0062] (3) Add 0.24 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, and heat under reflux for 48 h to carry out quaternization reaction;

[0063] (4) Distill the solution after the above quaternization reaction under reduced pressure until dry, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 4 .

[0064] Example 5:

[0065] (1) Add 0.5 mol of sodium dihydrogen phosphate and 188 g of distilled water to a four-necked flask, heat to 78 °C for dissolution, add dropwise 0.55 mol of epibromohydrin, keep warm for 3 h, and carry out phosphorylation reaction;

[0066] (2) Add 376 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0067] (3) Add 0.28 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, and heat under reflux for 36 h to carry out quaternization reaction;

[0068] (4) Distill the solution after the above quaternization reaction under reduced pressure until dry, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 5 .

[0069] Example 6:

[0070] (1) Add 0.5 mol of sodium dihydrogen phosphate and 190 g of distilled water to a four-necked flask, heat to 73 °C for dissolution, add dropwise 0.6 mol of epibromohydrin, keep warm for 2 h, and carry out phosphorylation reaction;

[0071] (2) Add 380 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0072] (3) Add 0.26 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, and heat under reflux for 42 h to carry out the quaternization reaction;

[0073] (4) Distill the solution after the above quaternization reaction under reduced pressure to dryness, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 6 .

[0074] Example 7:

[0075] (1) Add 0.5 mol of sodium dihydrogen phosphate and 200 g of distilled water to a four-necked flask, heat to 76 °C for dissolution, dropwise add 0.65 mol of epibromohydrin, and keep warm for 3 h to carry out the phosphorylation reaction;

[0076] (2) Add 400 g of ethanol to the above four-necked flask, cool down to below 20 °C, filter, and collect the filtrate;

[0077] (3) Add 0.25 mol of triethylenediamine to the above filtrate, adjust the pH to 8 - 9 with 2 mol / L sodium hydroxide solution, and heat under reflux for 18 h to carry out the quaternization reaction;

[0078] (4) Distill the solution after the above quaternization reaction under reduced pressure to dryness, and recrystallize with ethyl acetate to obtain the product hydrogen sulfide inhibitor S 7 .

[0079] Example 8: Evaluation of bactericidal rate

[0080] Add 500 mL of a fracturing fluid sample from a certain oil production plant in Shengli Oilfield to a series of narrow-mouth bottles. The contents of SRB (sulfate-reducing bacteria), TGB (saprophytic bacteria), and FB (iron bacteria) are 450 cells / mL, 110 cells / mL, and 110 cells / mL respectively. Add different concentrations of the hydrogen sulfide inhibitor S of the present invention 1 -S 7 , shake well, place in an oven at 62 °C, take samples after 1 h, and use the MPN method with three tubes to detect the remaining bacterial content and calculate the bactericidal rate. Use the commonly used oilfield bactericides dichlorophenol and dodecyl dimethyl benzyl ammonium chloride (1227) for comparative experiments. The test results are shown in Tables 1, 2, and 3.

[0081] Table 1 SRB bactericidal results (bactericidal rate, %)

[0082]

[0083]

[0084] As can be seen from Table 1: The hydrogen sulfide inhibitor S of the present invention 1-7When the concentration is 10 mg / L, the bactericidal rate against SRB reaches over 93%, with a maximum of 99.4% (S 7 ); when the concentration is 15 mg / L or higher, the bactericidal rate against SRB reaches 100%; while for the bactericides dichlorophenol and 1227, the bactericidal rates against SRB are both 0 when the concentration is 10 mg / L, and are 0 and 44.4% respectively when the concentration is 15 mg / L. Compared with the existing bactericides, the hydrogen sulfide inhibitor of the present invention has a good bactericidal effect on SRB.

[0085] Table 2 TGB Bactericidal Results (Bactericidal Rate, %)

[0086]

[0087]

[0088] As can be seen from Table 2: The hydrogen sulfide inhibitor S of the present invention 1-7 When the concentration is 10 mg / L, the bactericidal rate against TGB reaches over 93%, with a maximum of 99.6% (S 6 and S 7 ); when the concentration is 15 mg / L or higher, the bactericidal rate against TGB reaches 100%; while for dichlorophenol and 1227, the bactericidal rates against TGB are both 0 when the concentration is 10 mg / L, and are 0 and 59.1% respectively when the concentration is 15 mg / L. Compared with the existing bactericides, the hydrogen sulfide inhibitor of the present invention has a good bactericidal effect on TGB.

[0089] Table 3 FB Bactericidal Results (Bactericidal Rate, %)

[0090] Concentration, mg / L 10 15 20 30 <![CDATA[S 1 > 91.4 100 100 100 <![CDATA[S 2 > 93.2 100 100 100 <![CDATA[S 3 > 97.7 100 100 100 <![CDATA[S 4 > 98.6 100 100 100 <![CDATA[S 5 > 98.6 100 100 100 <![CDATA[S 6 > 99.2 100 100 100 <![CDATA[S 7 > 99.2 100 100 100 Diclofenol 0 0 13.6 59.1 1227 0 59.1 68.2 81.8

[0091] As can be seen from Table 3: The hydrogen sulfide inhibitor S of the present invention 1-7 When the concentration is 10 mg / L, the bactericidal rate against FB reaches over 91%, with a maximum of 99.2% (S 6 and S 7 ); when the concentration is 15 mg / L or higher, the bactericidal rate against FB reaches 100%; while for dichlorophenol and 1227, the bactericidal rates against FB are both 0 when the concentration is 10 mg / L, and are 0 and 59.1% respectively when the concentration is 15 mg / L. Compared with the existing bactericides, the hydrogen sulfide inhibitor of the present invention has a good bactericidal effect on FB.

[0092] Example 9: Field Test

[0093] A field test was carried out in a fracturing block of an oil production plant in Shengli Oilfield. A 2The contents of SRB, TGB, and FB (iron bacteria) in the well's backflow fluid are respectively: 450 cells / mL, 140 cells / mL, and 25 cells / mL, A 2 Well A mixes 15 mg / L of hydrogen sulfide inhibitor S during the injection of fracturing fluid 7 , A 2 The contents of SRB, TGB, and FB in the well's fracturing backflow fluid are all 0 cells / mL, and the bactericidal effect is good.

[0094] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.

Claims

1. A preparation method of a hydrogen sulfide inhibitor for fracturing, characterized in that, the preparation method includes: phosphating reaction of sodium dihydrogen phosphate and epihalohydrin at high temperature to generate phosphate ester; secondly, in a weakly alkaline environment, quaternization reaction of phosphate ester and triethylenediamine occurs under reflux state.

2. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 0.8 - 1.5 mole parts and 0.4 - 0.6 mole parts respectively.

3. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 2, characterized in that, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 1 - 1.5 mole parts and 0.45 - 0.55 mole parts respectively.

4. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 3, characterized in that, based on 1 mole part of sodium dihydrogen phosphate, the dosages of the epihalohydrin and triethylenediamine are 1 - 1.2 mole parts and 0.45 - 0.50 mole parts respectively.

5. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, the epihalohydrin is one of epichlorohydrin, epibromohydrin and epiiodohydrin.

6. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 5, characterized in that, the epihalohydrin is epichlorohydrin or epibromohydrin.

7. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, the high temperature condition is a temperature of 70 - 80 °C.

8. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 7, characterized in that, the high temperature condition is a temperature of 70 - 75 °C.

9. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, the phosphating reaction time is 1 - 4 h.

10. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 9, characterized in that, the phosphating reaction time is 2 - 3 h.

11. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, the weakly alkaline environment is pH 8 - 9.

12. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 1, characterized in that, the quaternization reaction time is 12 - 48 h.

13. The preparation method of a hydrogen sulfide inhibitor for fracturing according to claim 12, characterized in that, the quaternization reaction time is 18 - 36 h.

14. A hydrogen sulfide inhibitor for fracturing, characterized in that, the molecular structural formula of the hydrogen sulfide inhibitor is as follows:

15. The application of the hydrogen sulfide inhibitor for fracturing according to claim 14 in reservoir fracturing.

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