An oil and gas production filter aid and a process for its preparation

Abstract

The application belongs to the technical field of drilling, and particularly relates to an oil and gas exploitation filter aid and a preparation process thereof. The water-absorbing and oil-absorbing double-absorption resin is prepared from soluble starch and butyl methacrylate, and is used together with calcium silicate, calcium carbonate and a compounded oil-soluble resin to prepare the oil and gas exploitation filter aid. The application has good filtration loss performance based on the high specific surface area and porous structure of calcium silicate and the synergistic effect of other components.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of drilling, and particularly relates to an oil and gas exploitation filter aid and a preparation process thereof. BACKGROUND

[0002] In view of the current situation of unconventional oil and gas exploration and development, how to effectively control the fracture development degree of unconventional reservoirs during drilling operation has a great influence on the later production capacity. Realizing efficient protection of natural fractures in unconventional reservoirs is one of the main means to ensure the timely discovery and accurate evaluation of oil and gas reserves and improve the production of unconventional oil and gas reservoirs. The reservoir damage existing in the workover process of oil and gas reservoirs mainly includes solid phase invasion damage, liquid phase invasion damage, inorganic scale damage and water phase trapping damage; for different permeability formations, there is a situation of workover fluid loss and workover fluid pollution of the formation during the workover operation, but the existing additives cannot effectively plug the formations with different permeability, resulting in prolonged workover time and reduced oil well production.

[0003] A kind of oil and gas layer protection agent for drilling fluid is disclosed in Chinese patent (publication number CN118460191B), which is composed of calcium carbonate, oil-soluble resin, oil-absorbing swelling resin and water-absorbing swelling resin, and the oil-absorbing swelling resin is subjected to mild crosslinking treatment. Under certain pressure difference in the wellbore, the raw materials interact to form a shielding temporary plugging layer on the well wall, thereby preventing filtrate and drilling fluid from entering the formation, effectively preventing formation hydration and swelling, plugging formation bedding fissure, and preventing the migration of clay particles in the formation, suitable for temporary plugging in various wide fracture distribution scenarios. The filter aid in the prior art has the problem of poor filtration loss performance when applied in oil and gas exploitation, which affects its further popularization and use.

[0004] Therefore, there is an urgent need for an oil and gas exploitation filter aid that can promote the synergistic effect of components by modifying the components, thereby obtaining good filtration loss performance. SUMMARY

[0005] The purpose of the present application is to provide an oil and gas exploitation filter aid and a preparation process thereof. The water-absorbing and oil-absorbing double-absorbing resin is prepared from soluble starch and butyl methacrylate, and is used together with calcium silicate, calcium carbonate and compounded oil-soluble resin to prepare the oil and gas exploitation filter aid. Under the synergistic effect of the components, good filtration loss performance is obtained.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The first aspect of the present application provides a preparation process of an oil and gas exploitation filter aid, comprising the following steps:

[0008] S1: 20~30 parts by weight of soluble starch is added to 240~250 parts by weight of deionized water to stir and dissolve, then 16~20 parts by weight of butyl methacrylate, 0.8~1.2 parts by weight of N,N-methylene bisacrylamide, 0.8~1.2 parts by weight of divinylbenzene, 0.4~0.6 parts by weight of cerium nitrate and 0.4~0.6 parts by weight of azobisisobutyronitrile are mixed to carry out temperature rising reaction, to obtain double absorption resin;

[0009] S2: 60~70 parts by weight of calcium silicate, 40~50 parts by weight of calcium carbonate, 16~20 parts by weight of oil-soluble resin and 8~10 parts by weight of the double absorption resin are mixed to obtain oil and gas exploitation filter aid.

[0010] As a preferred scheme, the weight parts of the calcium carbonate in the application can be 40 parts, 42 parts, 44 parts, 46 parts, 48 parts or 50 parts, etc.

[0011] As a preferred scheme, the weight parts of the oil-soluble resin in the application can be 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc.

[0012] As a preferred scheme, the weight parts of the double absorption resin in the application can be 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts, etc.

[0013] As a preferred scheme, the conditions of the temperature rising reaction include: first stirring at a speed of 80~100 r / min for 50~60 min, then rising to 66~70℃ for constant temperature reaction for 4~6 h, methanol washing, suction filtration and drying.

[0014] The double absorption resin is prepared by using soluble starch and butyl methacrylate as raw materials, and connecting through chemical bonds under the action of crosslinking agent and initiator, so as to realize the coexistence of hydrophilic groups and lipophilic groups; the double absorption resin rapidly absorbs free water and oil to form a gel-like substance, thereby effectively reducing the fluid loss, and after absorbing the liquid, the resin expands to fill the pores and cracks, thereby reducing the fluid permeation to the formation, so as to reduce the fluid loss.

[0015] As a preferred scheme, the calcium carbonate is modified calcium carbonate.

[0016] The preparation method of the modified calcium carbonate comprises: 40~50 parts by weight of commercially available calcium carbonate is pretreated, then added to 150~160 parts by weight of anhydrous ethanol and 150~160 parts by weight of deionized water mixed solution to stir to obtain a slurry, then 2~4 parts by weight of vinyltrimethoxysilane is added to carry out coupling reaction to obtain an intermediate product; 40~50 parts by weight of the intermediate product is added to 300~360 parts by weight of deionized water, then 1~2 parts by weight of acrylamide and 1~2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid are added to carry out modification reaction to obtain modified calcium carbonate.

[0017] As a preferred solution, the pre-treatment conditions include: washing the calcium carbonate with acetone, drying and grinding.

[0018] As a preferred solution, the coupling reaction conditions include: adjusting the pH to 8.4-8.8, deoxygenating for 30-40 min under nitrogen, stirring at a speed of 160-200 r / min at a temperature of 60-70℃ for 2-4 h, filtering, washing with ethanol, and drying.

[0019] As a preferred solution, the modification reaction conditions include: adjusting the pH to neutral, adding 0.1-0.2 parts of ammonium persulfate after heating to 26-30℃ for 2-3 h, then heating to 48-50℃ for 3-4 h, centrifuging, washing with water, and drying.

[0020] The modified calcium carbonate has good physical plugging effect, can embed into the filter cake under the action of pressure difference, can reach the small pores between the clay particles, can accumulate and plug, can reduce the fluid flow area, and thus can control the fluid loss; at the same time, the hydration groups on the grafted polymer chains after modification of the calcium carbonate can combine with water molecules through hydrogen bonds to form a dense hydration layer, can establish a network structure between the clay particles and the fluid loss additive, can improve the stability of the dispersion system, the bridging effect of the molecular chains can make the clay particles not easy to aggregate, can form a thin and dense mud cake under the action of pressure difference, and can improve the fluid loss.

[0021] As a preferred solution, the oil-soluble resin is carbon five petroleum resin and rosin resin; and the mass ratio of the carbon five petroleum resin and the rosin resin is (1-3):1.

[0022] As a preferred solution, the mass ratio of the carbon five petroleum resin and the rosin resin can be 1:1, 1.5:1, 2:1, 2.5:1, or 3:1, etc.

[0023] As a preferred solution, the rosin resin is modified rosin resin.

[0024] The preparation method of the modified rosin resin includes: mixing 30-40 parts of rosin, 90-100 parts of fumaric acid, and 6-10 parts of deionized water by weight for addition reaction, then adding 8-12 parts of quercetin, 0.2-0.4 parts of zinc oxide, and 0.1-0.2 parts of lithium hydroxide for polycondensation reaction to obtain the modified rosin resin.

[0025] As a preferred solution, the addition reaction conditions include: placing under nitrogen protection, first melting the material at a temperature of 80-90℃, then heating under stirring at a temperature of 160-170℃ for 2-3 h.

[0026] As a preferred scheme, the polycondensation reaction conditions include: polycondensation at 200-210 DEG C for 100-120 min, cooling to room temperature, and discharging.

[0027] The modified rosin resin can be adsorbed on the well wall and the formation surface to form a dense film, reduce the filter into the formation, and simultaneously moderately improve the viscosity of the mud, improve the rheological property of the mud, help to stabilize the well wall, and reduce the permeation of the filter.

[0028] As a preferred scheme, the preparation step of the calcium silicate includes: adding 60-70 parts of fly ash into 180-200 parts of a sodium hydroxide solution with a mass concentration fraction of 8-10% by weight, stirring at 80-90 DEG C for 2-4 h, filtering to obtain a filtrate, mixing the filtrate with a saturated calcium hydroxide aqueous solution, reacting at 60-70 DEG C for 4-6 h, filtering to obtain a filter cake after the reaction is completed, adjusting the pH of the filter cake to 10-11, washing with water, and drying to obtain the calcium silicate.

[0029] The present application uses fly ash as raw material, and first generates sodium silicate by reacting amorphous silicon dioxide in fly ash with sodium hydroxide, and then generates solid active calcium silicate by reacting the sodium silicate with a saturated calcium hydroxide aqueous solution.

[0030] The calcium silicate has high specific surface area and porous structure, can effectively adsorb and intercept solid particles (such as clay and drill cuttings) in the drilling fluid or the fracturing fluid, reduce the turbidity of the fluid, and improve the filtration efficiency; meanwhile, the calcium silicate can form a dense and permeability-balanced filter cake in the drilling process, reduce the invasion of the filter into the formation, protect the reservoir permeability, and effectively improve the filtration performance.

[0031] The second aspect of the present application provides an oil and gas exploitation filter aid prepared by the process of the first aspect.

[0032] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0033] 1、The present application uses self-made calcium silicate as a main raw material, and cooperates with other functional components, wherein the modified rosin resin contains active groups of carboxyl, can react with hydroxyl groups introduced by soluble starch through double absorption resin, and the active groups of the modified rosin resin can also be combined with modified calcium carbonate and its polymers, so as to build a physical barrier and form a network structure with high viscosity and good plugging performance, effectively reduce the further penetration of the drilling fluid or the fracturing fluid into the formation, and significantly reduce the filtration loss.

[0034] 2. The dual-absorbent resin of the present invention uses soluble starch and butyl methacrylate as raw materials, which are linked by chemical bonds under the action of crosslinking agent and initiator to achieve the coexistence of hydrophilic and lipophilic groups; the dual-absorbent resin rapidly absorbs free water and oil to form a gel-like substance, thereby effectively reducing liquid loss. At the same time, after absorbing liquid, the resin expands to fill pores and cracks, reducing fluid infiltration into the formation, thereby reducing the amount of filtration loss.

[0035] 3. The modified calcium carbonate of this invention has a good physical filling and pore-blocking effect. Under the action of pressure difference, it is embedded in the filter cake and can reach the small pores between clay particles, accumulate and block them, reduce the fluid flow area, and thus control the water loss. At the same time, the hydration groups on the grafted polymer chains of the modified calcium carbonate combine with water molecules through hydrogen bonds to form a dense hydration layer, establish a network structure between clay particles and filtration loss reducer, improve the stability of the dispersion system, and the bridging effect of molecular chains makes it difficult for clay particles to aggregate. Under the action of pressure difference, a thin and dense mud cake is formed, reducing filtration loss.

[0036] 4. The modified rosin resin of the present invention can be adsorbed on the well wall and formation surface to form a dense film, reducing the amount of filtrate entering the formation; at the same time, it can moderately increase the viscosity of the mud, improve the rheological properties of the mud, help stabilize the well wall, and reduce the penetration of filtrate.

[0037] 5. The calcium silicate of the present invention has a high specific surface area and porous structure, which can effectively adsorb and retain solid particles (such as clay and drill cuttings) in drilling fluid or fracturing fluid, reduce fluid turbidity, and improve filtration efficiency. At the same time, during the drilling process, calcium silicate can form a dense and uniformly permeable filter cake, reduce the intrusion of filtrate into the formation, protect reservoir permeability, and effectively improve filtration performance. Attached Figure Description

[0038] Figure 1 The image shows a SEM image of the calcium silicate prepared in Example 1. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The sources of some components in the examples and comparative examples are as follows:

[0041] Commercially available calcium carbonate, model MP-Rh, with a particle size of 0.5μm, was purchased from Guangxi Huana New Materials Co., Ltd.

[0042] C5 petroleum resin, item number SYSZ01, purchased from Jinan Shanhai Chemical Technology Co., Ltd.

[0043] Rosin, trade name HC3444, purchased from Tianmen Hengchang Chemical Co., Ltd.

[0044] Rubber powder, trade name 5561254, purchased from Dongguan Shenghao Plastic Raw Material Co., Ltd.

[0045] Polyacrylic acid resin, trade name P756765, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0046] Soluble starch, CAS No. 9005-84-9, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0047] Butyl methacrylate, CAS No. 97-88-1, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0048] N,N-methylenebisacrylamide, CAS No. 110-26-9, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0049] Divinylbenzene, CAS No. 105-06-6, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0050] Cerium nitrate, CAS No. 13093-17-9, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0051] Azobisisobutyronitrile, CAS No. 78-67-1, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0052] Vinyltrimethoxysilane, CAS No. 2768-02-7, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0053] Acrylamide, CAS No. 79-06-1, purchased from Shanghai Melin Biochemical Technology Co., Ltd.

[0054] 2-Acrylamido-2-methylpropanesulfonic acid, CAS No. 15214-89-8, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0055] Ammonium persulfate, CAS No. 7727-54-0, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0056] Rosin, CAS No. 8050-09-7, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0057] Fumaric acid, CAS No. 110-17-8, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0058] Tetrahydrofurfuryl alcohol, CAS No. 115-77-5, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0059] Zinc oxide, CAS No. 1314-13-2, purchased from Shanghai Maikelin Biochemical Science and Technology Co., Ltd.

[0060] Lithium hydroxide, CAS No. 1310-65-2, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0061] Example 1

[0062] The present embodiment provides a preparation process of oil and gas exploitation filter aid, comprising the following steps:

[0063] S1: 30 parts of soluble starch is added to 250 parts of deionized water for stirring and dissolving, then 20 parts of butyl methacrylate, 1.2 parts of N,N-methylene bisacrylamide, 1.2 parts of divinylbenzene, 0.6 parts of cerous nitrate and 0.6 parts of azobisisobutyronitrile are mixed for temperature rising reaction, first stirring at a speed of 100 r / min for 50 min, then heating to 70℃ for constant temperature reaction for 4h, methanol washing, suction filtration, drying, to obtain double absorption resin;

[0064] S2: 70 parts of calcium silicate, 50 parts of modified calcium carbonate, 20 parts of oil-soluble resin (15 parts of carbon five petroleum resin and 5 parts of modified rosin resin) and 10 parts of the double absorption resin are mixed to obtain oil and gas exploitation filter aid.

[0065] Preparation of the modified calcium carbonate: 50 parts of commercially available calcium carbonate is pretreated (washed with acetone, dried and ground), then added to a mixture of 160 parts of anhydrous ethanol and 160 parts of deionized water for stirring to obtain a slurry, then 4 parts of vinyltrimethoxysilane is added for coupling reaction, the pH is adjusted to 8.8, deoxygenated by nitrogen for 40 min, stirred at a speed of 160 r / min at a temperature of 70℃ for 4h, filtered, washed with ethanol and dried to obtain an intermediate product; 50 parts of the intermediate product is added to 360 parts of deionized water, then 2 parts of acrylamide and 2 parts of 2-acrylamido-2-methylpropanesulfonic acid are added for modification reaction, the pH is adjusted to neutral, heated to 30℃, then 0.2 parts of ammonium persulfate is added for reaction for 2h, then heated to 50℃ for 3h, centrifuged, washed with water and dried to obtain modified calcium carbonate.

[0066] Preparation of the modified rosin resin: 40 parts of rosin, 100 parts of fumaric acid and 10 parts of deionized water are mixed for addition reaction, placed in nitrogen protection, first melt the material at a temperature of 90℃, then heated to 170℃ for heating reaction for 2h under stirring; after the reaction is completed, 12 parts of quercetin, 0.4 parts of zinc oxide and 0.2 parts of lithium hydroxide are added for polycondensation reaction, polycondensed at a temperature of 210℃ for 100 min, cooled to room temperature, discharged, to obtain modified rosin resin.

[0067] The preparation of the calcium silicate: 70 parts of fly ash is added to 200 parts of a sodium hydroxide solution with a mass concentration fraction of 10%, stirred at 90℃ for 2h, and a filtrate is obtained by filtration. The filtrate is mixed with a saturated calcium hydroxide aqueous solution, and reacted at 70℃ for 4h. After the reaction is completed, a filter cake is obtained by filtration. The pH of the filter cake is adjusted to 11, and the filter cake is washed with water and dried to obtain the calcium silicate.

[0068] Example 2

[0069] The present embodiment provides a preparation process of an oil and gas exploitation filter aid, comprising the following steps:

[0070] S1: 20 parts of soluble starch is added to 240 parts of deionized water and stirred to dissolve, then 16 parts of butyl methacrylate, 0.8 parts of N,N-methylene bisacrylamide, 0.8 parts of divinylbenzene, 0.4 parts of cerous nitrate and 0.4 parts of azobisisobutyronitrile are mixed to perform a temperature rising reaction. First, stir at a speed of 80r / min for 60min, then heat to 66℃ and keep the temperature constant for 6h. Methanol is used for washing, suction filtration and drying to obtain a double absorption resin;

[0071] S2: 60 parts of calcium silicate, 40 parts of modified calcium carbonate, 16 parts of oil-soluble resin (8 parts of carbon five petroleum resin and 8 parts of modified rosin resin) and 8 parts of the double absorption resin are mixed to obtain an oil and gas exploitation filter aid.

[0072] The preparation of the modified calcium carbonate: 40 parts of commercially available calcium carbonate is pretreated (washed with acetone, dried and ground), then added to a mixture of 150 parts of anhydrous ethanol and 150 parts of deionized water to obtain a slurry, then 2 parts of vinyltrimethoxysilane is added to perform a coupling reaction, the pH is adjusted to 8.4, and the oxygen is removed by nitrogen for 30min. Stir at a speed of 160r / min at a temperature of 60℃ for 4h, filter, wash with ethanol and dry to obtain an intermediate product. 40 parts of the intermediate product is added to 300 parts of deionized water, then 1 part of acrylamide and 1 part of 2-acrylamido-2-methylpropanesulfonic acid are added to perform a modification reaction, the pH is adjusted to neutral, heated to 26℃, then 0.1 parts of ammonium persulfate is added and reacted for 3h, then heated to 48℃ for 4h, centrifuged, washed with water and dried to obtain the modified calcium carbonate.

[0073] The preparation of the modified rosin resin: 30 parts of rosin, 90 parts of fumaric acid and 6 parts of deionized water are mixed for addition reaction, placed under nitrogen protection, the material is first melted at a temperature of 80℃, then heated to 160℃ under stirring for 3h; after the reaction is completed, 8 parts of quercetin, 0.2 parts of zinc oxide and 0.1 parts of lithium hydroxide are added for polycondensation reaction, and the polycondensation is carried out at 200℃ for 120min, cooled to room temperature, discharged, and the modified rosin resin is obtained.

[0074] The preparation steps of the calcium silicate include: 60 parts of fly ash are added to 180 parts of sodium hydroxide solution with a mass concentration fraction of 8%, stirred at 80℃ for 4h, and the filtrate is obtained by filtration, the filtrate is mixed with saturated calcium hydroxide aqueous solution, and the reaction is carried out at 60℃ for 6h, and the filter cake is obtained by filtration after the reaction is completed, the pH of the filter cake is adjusted to 10, washed with water, and dried to obtain the calcium silicate.

[0075] Example 3

[0076] The present embodiment provides a preparation process of oil and gas exploitation filter aid, which comprises the following steps:

[0077] S1: 25 parts of soluble starch are added to 245 parts of deionized water for stirring and dissolving, then 18 parts of butyl methacrylate, 1.0 parts of N,N-methylene bisacrylamide, 1.0 parts of divinylbenzene, 0.5 parts of cerium nitrate and 0.5 parts of azobisisobutyronitrile are mixed for temperature rising reaction, first stirred at a speed of 90r / min for 55min, then heated to 68℃ for constant temperature reaction for 5h, washed with methanol, suction filtered and dried to obtain the double absorption resin;

[0078] S2: 65 parts of calcium silicate, 45 parts of modified calcium carbonate, 18 parts of oil-soluble resin (10 parts of carbon five petroleum resin and 8 parts of modified rosin resin) and 9 parts of the double absorption resin are mixed to obtain the oil and gas exploitation filter aid.

[0079] The preparation of the modified calcium carbonate: 45 parts of commercially available calcium carbonate is pretreated (cleaned with acetone, dried and ground), then added to a mixture of 155 parts of anhydrous ethanol and 155 parts of deionized water to obtain a slurry, then 3 parts of vinyl trimethoxysilane is added for coupling reaction, the pH is adjusted to 8.6, deoxidized by nitrogen for 35 min, stirred at a speed of 180 r / min at a temperature of 65℃ for 3h, filtered, washed with ethanol, and dried to obtain an intermediate product; 45 parts of the intermediate product is added to 330 parts of deionized water, then 1.4 parts of acrylamide and 1.4 parts of 2-acrylamido-2-methylpropanesulfonic acid are added for modification reaction, the pH is adjusted to neutral, heated to 28℃, then 0.2 parts of ammonium persulfate is added and reacted for 2h, then heated to 49℃ for 3.5h, centrifuged, washed with water, and dried to obtain the modified calcium carbonate.

[0080] The preparation of the modified rosin resin: 35 parts of rosin, 95 parts of fumaric acid and 8 parts of deionized water are mixed for addition reaction, placed in a nitrogen atmosphere, the material is first melted at a temperature of 84℃, then heated to 168℃ under stirring for 2.4h of heating reaction; after the reaction is completed, 10 parts of quercetin, 0.3 parts of zinc oxide and 0.16 parts of lithium hydroxide are added for polycondensation reaction, polycondensed at a temperature of 204℃ for 110 min, cooled to room temperature, discharged, and the modified rosin resin is obtained.

[0081] The preparation steps of the calcium silicate include: 65 parts of fly ash is added to 190 parts of a sodium hydroxide solution with a mass concentration fraction of 9%, stirred at a temperature of 85℃ for 3h, filtered to obtain a filtrate, the filtrate is mixed with a saturated calcium hydroxide aqueous solution, reacted at a temperature of 65℃ for 5h, after the reaction is completed, the filter cake is filtered to obtain a filter cake, the pH of the filter cake is adjusted to 10.5, washed with water, and dried to obtain the calcium silicate.

[0082] Example 4

[0083] The difference between this example and Example 1 is that commercially available calcium carbonate (model MP-Rh) is used instead of modified calcium carbonate.

[0084] Example 5

[0085] The difference between this example and Example 1 is that commercially available rosin resin (item number HC3444) is used instead of modified rosin resin.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that 8 parts of rubber powder (item number 5561254) and 2 parts of polyacrylic acid resin (item number P756765) are used instead of 10 parts of double-suction resin.

[0088] Comparative Example 2

[0089] The difference between the present comparative example and Example 1 is that the amount of C5 petroleum resin in 20 parts of oil-soluble resin is changed to 18 parts, and the amount of modified rosin resin is changed to 2 parts.

[0090] Comparative Example 3

[0091] The difference between the present comparative example and Example 1 is that the amount of C5 petroleum resin in 20 parts of oil-soluble resin is changed to 5 parts, and the amount of modified rosin resin is changed to 15 parts.

[0092] Performance test

[0093] The above examples and comparative examples are tested as follows:

[0094] (1) Preparation of base slurry: 400 mL of deionized water + 0.42 g of anhydrous sodium carbonate + 12 g of bentonite for drilling fluid slurry preparation.

[0095] (2) Preparation of sample slurry: base slurry + 5wt% filter aid (prepared in the examples and comparative examples).

[0096] (3) High-speed stirring for 5 min, and testing the filtration performance API and HTHP (80°C, 3.5 MPa) of the base slurry and the sample slurry, respectively, and the filtration performance test is carried out according to the specific content of Chapter 7 of GB / T 16783.1-2014 Petroleum and Natural Gas Industry Drilling Fluids Field Testing Part 1: Water-based Drilling Fluids.

[0097] Table 1 Performance test results

[0098]

[0099] From the above performance test results, it can be seen that the comprehensive performance of Examples 1-3 is the best, with API of 6.1-6.4 mL and HTHP of 39.6-40.1 mL; this is mainly because the water-absorbing and oil-absorbing double-absorbing resin is prepared from soluble starch and butyl methacrylate, and is used together with calcium silicate, modified calcium carbonate and compounded oil-soluble resin (containing modified rosin resin), thereby obtaining good filtration performance.

[0100] Compared with Example 1, Example 4 uses commercially available calcium carbonate (model MP-Rh) instead of modified calcium carbonate, so that the API becomes larger and the HTHP increases; compared with Example 1, Example 5 uses commercially available rosin resin (item number HC3444) instead of modified rosin resin, so that the API becomes larger and the HTHP increases; compared with Example 1, Comparative Example 1 uses 8 parts of rubber powder (item number 5561254) and 2 parts of polyacrylic acid resin (item number P756765) instead of 10 parts of double-suction resin, so that the API becomes larger and the HTHP increases; compared with Example 1, in Comparative Example 2, the amount of carbon five petroleum resin in 20 parts of oil-soluble resin is changed to 18 parts, and the amount of modified rosin resin is changed to 2 parts, and because the amount of modified rosin resin is too small, the compounding effect is not good, so that the API becomes larger and the HTHP increases; compared with Example 1, in Comparative Example 3, the amount of carbon five petroleum resin in 20 parts of oil-soluble resin is changed to 5 parts, and the amount of modified rosin resin is changed to 15 parts, and because the amount of modified rosin resin is too large, the compounding effect is not good, so that the API becomes larger and the HTHP increases.

Claims

1. A preparation process for an oil and gas extraction filter aid, characterized in that, Includes the following steps: S1: By weight, 20-30 parts of soluble starch are added to 240-250 parts of deionized water and stirred to dissolve. Then, 16-20 parts of butyl methacrylate, 0.8-1.2 parts of N,N-methylenebisacrylamide, 0.8-1.2 parts of divinylbenzene, 0.4-0.6 parts of cerium nitrate and 0.4-0.6 parts of azobisisobutyronitrile are added and the mixture is heated to obtain a double-absorbent resin. S2: By weight, 60-70 parts of calcium silicate, 40-50 parts of calcium carbonate, 16-20 parts of oil-soluble resin and 8-10 parts of the dual-absorbent resin are mixed to obtain an oil and gas extraction filter aid. The preparation steps of the calcium silicate include: adding 60-70 parts by weight of fly ash to 180-200 parts by weight of sodium hydroxide solution with a mass concentration of 8-10%, stirring at 80-90℃ for 2-4 hours, filtering to obtain filtrate, mixing the filtrate with saturated calcium hydroxide aqueous solution, reacting at 60-70℃ for 4-6 hours, filtering after the reaction is completed to obtain filter cake, adjusting the pH of the filter cake to 10-11, washing with water, drying, and obtaining the calcium silicate.

2. The preparation process of an oil and gas extraction filter aid according to claim 1, characterized in that, The conditions for the heating reaction include: stirring at 80-100 r / min for 50-60 min, then heating to 66-70℃ and reacting at a constant temperature for 4-6 h, followed by washing with methanol, filtration, and drying.

3. The preparation process of an oil and gas extraction filter aid according to claim 1, characterized in that, The calcium carbonate is modified calcium carbonate; The method for preparing the modified calcium carbonate includes: pretreating 40-50 parts by weight of commercially available calcium carbonate, then adding it to a mixture of 150-160 parts of anhydrous ethanol and 150-160 parts of deionized water and stirring to obtain a slurry; then adding 2-4 parts of vinyltrimethoxysilane for a coupling reaction to obtain an intermediate product; adding 40-50 parts of the intermediate product to 300-360 parts of deionized water, then adding 1-2 parts of acrylamide and 1-2 parts of 2-acrylamido-2-methylpropanesulfonic acid for a modification reaction to obtain modified calcium carbonate.

4. The preparation process of an oil and gas extraction filter aid according to claim 3, characterized in that, The conditions for the coupling reaction include: adjusting the pH to 8.4-8.8, purging with nitrogen to remove oxygen for 30-40 min, stirring at 160-200 r / min for 2-4 h at a temperature of 60-70℃, filtering, washing with ethanol, and drying.

5. The preparation process of an oil and gas extraction filter aid according to claim 3, characterized in that, The conditions for the modification reaction include: adjusting the pH to neutral, heating to 26-30℃, adding 0.1-0.2 parts of ammonium persulfate and reacting for 2-3 hours, then heating to 48-50℃ and holding for 3-4 hours, centrifuging, washing with water, and drying.

6. The preparation process of an oil and gas extraction filter aid according to claim 1, characterized in that, The oil-soluble resin is a C5 petroleum resin and a rosin resin; the mass ratio of the C5 petroleum resin and the rosin resin is (1~3):

1.

7. The preparation process of an oil and gas extraction filter aid according to claim 6, characterized in that, The rosin resin is a modified rosin resin; The method for preparing the modified rosin resin includes: mixing 30-40 parts of rosin, 90-100 parts of fumaric acid and 6-10 parts of deionized water by weight for an addition reaction, and then adding 8-12 parts of pentaerythritol, 0.2-0.4 parts of zinc oxide and 0.1-0.2 parts of lithium hydroxide for a polycondensation reaction to obtain the modified rosin resin.

8. The preparation process of an oil and gas extraction filter aid according to claim 7, characterized in that, The conditions for the addition reaction include: under nitrogen protection, first melting the material at a temperature of 80~90℃, and then heating it to 160~170℃ for 2~3 hours under stirring.

9. A filter aid for oil and gas extraction, characterized in that, It is prepared according to any one of claims 1 to 8.

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