Oil and gas exploitation filter aid and preparation process thereof

Abstract

The invention belongs to the technical field of well 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 the soluble starch and the butyl methacrylate, and the calcium silicate, the calcium carbonate and the compound oil-soluble resin are used together, so that the oil and gas exploitation filter aid is prepared; based on the high specific surface area and the porous structure of calcium silicate, and in combination with the synergistic effect of other components, good filtration performance is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling, and in particular relates to an oil and gas mining filter aid and a preparation process thereof. Background Art

[0002] In view of the current status of unconventional oil and gas exploration and development, how to effectively control the degree of unconventional reservoir fracture development during drilling construction has a great impact on the subsequent production capacity. Achieving 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 to increase the production of unconventional oil and gas reservoirs. The reservoir damage that occurs to oil and gas reservoirs during the well repair process mainly includes solid phase invasion damage, liquid phase invasion damage, inorganic scale damage and water phase closure damage; for formations with different permeabilities, there is leakage of well repair fluid during the well repair operation, resulting in the loss of well repair fluid and the contamination of the formation by the well repair fluid. However, the existing additives cannot effectively block formations with different permeabilities, resulting in extended well repair time and reduced oil well production.

[0003] A Chinese patent (publication number CN118460191B) discloses an oil and gas formation protective agent for drilling fluids. The invention consists of calcium carbonate, an oil-soluble resin, an oil-swellable resin, and a water-swellable resin. The oil-swellable resin is lightly cross-linked. These ingredients interact with each other under a certain pressure differential within the wellbore to form a temporary barrier layer on the wellbore wall, thereby preventing filtrate and drilling fluid from entering the formation. This effectively prevents formation hydration and expansion, seals formation fissures, and prevents the migration of clay particles within the formation. This protective layer is suitable for temporary plugging in a variety of wide fracture distribution scenarios. Existing filter aids in oil and gas production suffer from poor fluid loss performance, hindering their further promotion and use.

[0004] Therefore, there is an urgent need for an oil and gas production filter aid that can modify the components to promote the synergistic effect of the components and thus obtain good filtration performance. Summary of the Invention

[0005] The present invention aims to provide an oil and gas production filter aid and a preparation process thereof. A water- and oil-absorbing double-absorption resin is prepared from soluble starch and butyl methacrylate, and calcium silicate, calcium carbonate, and a compounded oil-soluble resin are used together to prepare the oil and gas production filter aid. The synergistic effect of the components achieves good fluid loss performance.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A first aspect of the present invention provides a process for preparing a filter aid for oil and gas production, comprising the following steps: S1: In parts by weight, 20-30 parts of soluble starch are added to 240-250 parts of deionized water, stirred and dissolved, and 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, mixed and heated to react to obtain a double-absorption resin; S2: In parts 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 double-absorption resin are mixed to obtain an oil and gas production filter aid.

[0007] As a preferred solution, the weight parts of calcium carbonate in the present invention can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts or 50 parts, etc.

[0008] As a preferred solution, the weight proportion of the oil-soluble resin in the present invention can be 16 parts, 17 parts, 18 parts, 19 parts or 20 parts.

[0009] As a preferred solution, the weight proportion of the double-absorption resin in the present invention can be 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts.

[0010] As a preferred solution, the temperature reaction conditions include: stirring at a speed of 80-100 r / min for 50-60 min, then heating to 66-70° C. and reacting at a constant temperature for 4-6 h, washing with methanol, filtering, and drying.

[0011] Double-absorption resin is made of soluble starch and butyl methacrylate, which are connected by chemical bonds under the action of cross-linking agents and initiators to achieve the coexistence of hydrophilic groups and lipophilic groups; the double-absorption resin quickly absorbs free water and oil to form a gel-like substance, thereby effectively reducing liquid loss. At the same time, after absorbing the liquid, the resin expands to fill pores and cracks, reducing the penetration of fluid into the formation, thereby reducing the amount of fluid loss.

[0012] As a preferred solution, the calcium carbonate is modified calcium carbonate; The preparation method of the modified calcium carbonate comprises: pretreating 40-50 parts of commercially available calcium carbonate by weight, adding the pretreatment to a mixture of 150-160 parts of anhydrous ethanol and 150-160 parts of deionized water, stirring to obtain a slurry, then adding 2-4 parts of vinyltrimethoxysilane to carry out 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 to carry out a modification reaction to obtain the modified calcium carbonate.

[0013] As a preferred solution, the pretreatment conditions include: washing the calcium carbonate with acetone, drying and grinding.

[0014] As a preferred solution, the coupling reaction conditions include: adjusting the pH to 8.4-8.8, deoxygenating with nitrogen for 30-40 minutes, stirring at a temperature of 60-70°C and a speed of 160-200 r / min for 2-4 hours, filtering, washing with ethanol, and drying.

[0015] As a preferred solution, the modification reaction conditions include: adjusting the pH to neutral, heating to 26-30°C, adding 0.1-0.2 parts of ammonium persulfate and reacting for 2-3 hours, then heating to 48-50°C and keeping warm for 3-4 hours, centrifuging, washing with water, and drying.

[0016] Modified calcium carbonate has a good physical filling and plugging effect. It is embedded in the filter cake under the action of pressure difference and can reach the tiny pores between the clay, accumulate and seal them, reduce the fluid flow area, and thus control the water loss. At the same time, the hydration groups on the grafted polymer chain after calcium carbonate modification combine with water molecules through hydrogen bonds to form a dense hydration layer, establish a network structure between clay particles and the fluid loss reducer, and improve the stability of the dispersion system. The bridging effect of the molecular chain makes it difficult for clay particles to agglomerate, forming a thin and dense mud cake under the action of pressure difference, thereby increasing the fluid loss.

[0017] As a preferred solution, the oil-soluble resin is C5 petroleum resin and rosin resin; the mass ratio of the C5 petroleum resin to the rosin resin is (1-3):1.

[0018] As a preferred solution, the mass ratio of the C5 petroleum resin to the rosin resin can be 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, etc.

[0019] As a preferred solution, the rosin resin is modified rosin resin; The preparation method of the modified rosin resin comprises: mixing 30-40 parts of rosin, 90-100 parts of fumaric acid and 6-10 parts of deionized water, carrying out 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 to carry out a condensation reaction to obtain the modified rosin resin.

[0020] As a preferred solution, the conditions of the addition reaction include: placing the material under nitrogen protection, first melting the material at a temperature of 80-90°C, and then heating it to 160-170°C under stirring for a heating reaction of 2-3 hours.

[0021] As a preferred solution, the conditions of the polycondensation reaction include: polycondensation at 200-210° C. for 100-120 min, cooling to room temperature, and discharging.

[0022] Modified rosin resin can be adsorbed on the well wall and formation surface to form a dense film, reducing the filtrate from 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 the filtrate.

[0023] As a preferred solution, the preparation step of the calcium silicate includes: adding 60 to 70 parts by weight of fly ash to 180 to 200 parts of a sodium hydroxide solution with a mass concentration of 8 to 10%, stirring at 80 to 90° C. for 2 to 4 hours, filtering to obtain a filtrate, mixing the filtrate with a saturated calcium hydroxide aqueous solution, reacting at 60 to 70° C. for 4 to 6 hours, filtering after the reaction is completed to obtain a filter cake, adjusting the pH of the filter cake to 10 to 11, washing with water, and drying to obtain the calcium silicate.

[0024] The invention uses fly ash as raw material, firstly reacts amorphous silicon dioxide in the fly ash with sodium hydroxide to generate sodium silicate, and then reacts the sodium silicate with a saturated calcium hydroxide aqueous solution to generate solid active calcium silicate.

[0025] The calcium silicate of the present invention has a high specific surface area and a 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, the calcium silicate can form a dense filter cake with balanced permeability, reducing the intrusion of filtrate into the formation, protecting the permeability of the reservoir, and thus effectively improving the filtration performance.

[0026] The second aspect of the present invention provides an oil and gas production filter aid prepared by the process described in the first aspect.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are: 1. The present invention uses homemade calcium silicate as the main raw material and works together with other functional components. The modified rosin resin contains an active group carboxyl, which can react with the hydroxyl group introduced by the double-absorption resin through soluble starch. At the same time, the active group of the modified rosin resin can also combine with modified calcium carbonate and its polymer, thereby constructing a physical barrier and forming a network structure with high viscosity and good sealing performance, effectively reducing the further penetration of drilling fluid or fracturing fluid into the formation and significantly reducing the fluid loss.

[0028] 2. The double-absorption resin of the present invention uses soluble starch and butyl methacrylate as raw materials, which are connected by chemical bonds under the action of a cross-linking agent and an initiator to achieve the coexistence of hydrophilic and lipophilic groups. The double-absorption resin rapidly absorbs free water and oil to form a gel-like substance, thereby effectively reducing liquid loss. At the same time, after absorbing the liquid, the resin expands to fill pores and cracks, reducing the penetration of fluid into the formation, thereby reducing the amount of fluid loss.

[0029] 3. The modified calcium carbonate of the present invention has a good physical filling and plugging effect. Under the action of pressure differential, it embeds into the filter cake and can reach the tiny pores between the clay, accumulate and block them, reducing the fluid flow area, thereby controlling the water loss. At the same time, after the calcium carbonate is modified, the hydration groups on the grafted polymer chain combine with water molecules through hydrogen bonds to form a dense hydration layer, establishing a network structure between the clay particles and the fluid loss reducer, improving the stability of the dispersion system, and the bridging effect of the molecular chain makes it difficult for the clay particles to agglomerate. Under the action of pressure differential, a thin and dense mud cake is formed, reducing the fluid loss.

[0030] 4. The modified rosin resin of the present invention can be adsorbed on the well wall and the formation surface to form a dense film, reducing the filtrate from 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 the filtrate.

[0031] 5. The calcium silicate of the present invention has a high specific surface area and a 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 filter cake with balanced permeability, reduce the intrusion of filtrate into the formation, protect the permeability of the reservoir, and effectively improve the filtration performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the SEM image of the calcium silicate prepared in Example 1. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] The sources of some components in the Examples and Comparative Examples are as follows: Commercially available calcium carbonate, model MP-Rh, with a particle size of 0.5 μm, was purchased from Guangxi Huana New Materials Co., Ltd. C5 petroleum resin, product number SYSZ01, was purchased from Jinan Shanhai Chemical Technology Co., Ltd. Commercially available rosin resin, product number HC3444, was purchased from Tianmen Hengchang Chemical Co., Ltd. Rubber powder, item number 5561254, purchased from Dongguan Shenghao Plastic Raw Materials Co., Ltd. Polyacrylic acid resin, product number P756765, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Soluble starch, CAS No. 9005-84-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Butyl methacrylate, CAS No. 97-88-1, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; N,N-Methylenebisacrylamide, CAS No. 110-26-9, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Divinylbenzene, CAS No. 105-06-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Cerium nitrate, CAS No. 13093-17-9, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Azobisisobutyronitrile, CAS No. 78-67-1, was purchased from Sinopharm Chemical Reagent Co., Ltd. Vinyltrimethoxysilane, CAS No. 2768-02-7, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Acrylamide, CAS No. 79-06-1, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; 2-Acrylamido-2-methylpropanesulfonic acid, CAS No. 15214-89-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Ammonium persulfate, CAS No. 7727-54-0, was purchased from Sinopharm Chemical Reagent Co., Ltd. Rosin, CAS No. 8050-09-7, was purchased from Sinopharm Chemical Reagent Co., Ltd. Fumaric acid, CAS No. 110-17-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Pentaerythritol, CAS No. 115-77-5, was purchased from Sinopharm Chemical Reagent Co., Ltd. Zinc oxide, CAS No. 1314-13-2, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Lithium hydroxide, CAS No. 1310-65-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0035] Example 1 This embodiment provides a preparation process for an oil and gas production filter aid, comprising the following steps: S1: In parts by weight, 30 parts of soluble starch were added to 250 parts of deionized water, and stirred to dissolve. Then, 20 parts of butyl methacrylate, 1.2 parts of N,N-methylenebisacrylamide, 1.2 parts of divinylbenzene, 0.6 parts of cerium nitrate and 0.6 parts of azobisisobutyronitrile were added, mixed and heated to react. The mixture was stirred at a speed of 100 r / min for 50 minutes, and then heated to 70°C for constant temperature reaction for 4 hours. The mixture was washed with methanol, filtered and dried to obtain a double-absorption resin. S2: In parts by weight, 70 parts of calcium silicate, 50 parts of modified calcium carbonate, 20 parts of oil-soluble resin (15 parts of C5 petroleum resin and 5 parts of modified rosin resin) and 10 parts of the double-absorption resin are mixed to obtain an oil and gas production filter aid.

[0036] The modified calcium carbonate is prepared as follows: 50 parts by weight of commercially available calcium carbonate are pretreated (cleaned with acetone, dried and ground), then added to a mixture of 160 parts of anhydrous ethanol and 160 parts of deionized water and stirred to obtain a slurry; 4 parts of vinyltrimethoxysilane are added for a coupling reaction; the pH is adjusted to 8.8, nitrogen is passed through the mixture for deoxygenation for 40 minutes, the mixture is stirred at 160 r / min at a temperature of 70° C. for 4 hours, filtered, washed with ethanol, and dried to obtain an intermediate product; 50 parts of the intermediate product are added to 360 parts of deionized water, 2 parts of acrylamide and 2 parts of 2-acrylamido-2-methylpropanesulfonic acid are added for a modification reaction, the pH is adjusted to neutral, the mixture is heated to 30° C., 0.2 parts of ammonium persulfate are added for a reaction for 2 hours, the mixture is heated to 50° C. and kept warm for 3 hours, centrifuged, washed with water, and dried to obtain the modified calcium carbonate.

[0037] The modified rosin resin is prepared by mixing 40 parts by weight of rosin, 100 parts of fumaric acid, and 10 parts of deionized water for an addition reaction. The mixture is first melted at 90° C. under nitrogen protection, and then heated to 170° C. with stirring for a heating reaction for 2 hours. After the reaction is completed, 12 parts of pentaerythritol, 0.4 parts of zinc oxide, and 0.2 parts of lithium hydroxide are added for a condensation reaction. The mixture is polycondensed at 210° C. for 100 minutes, cooled to room temperature, and discharged to obtain the modified rosin resin.

[0038] The preparation of the calcium silicate is as follows: 70 parts by weight of fly ash are added to 200 parts of a sodium hydroxide solution with a mass concentration of 10%, stirred at 90° C. for 2 hours, filtered to obtain a filtrate, the filtrate is mixed with a saturated calcium hydroxide aqueous solution, reacted at 70° C. for 4 hours, filtered after the reaction is completed to obtain a filter cake, the filter cake is adjusted to a pH of 11, washed with water, and dried to obtain the calcium silicate.

[0039] Example 2 This embodiment provides a preparation process for an oil and gas production filter aid, comprising the following steps: S1: In parts by weight, 20 parts of soluble starch were added to 240 parts of deionized water, and stirred to dissolve. Then, 16 parts of butyl methacrylate, 0.8 parts of N,N-methylenebisacrylamide, 0.8 parts of divinylbenzene, 0.4 parts of cerium nitrate and 0.4 parts of azobisisobutyronitrile were added, mixed and heated to react. The mixture was stirred at a speed of 80 r / min for 60 minutes, and then heated to 66°C for constant temperature reaction for 6 hours. The mixture was washed with methanol, filtered and dried to obtain a double-absorption resin. S2: In parts by weight, 60 parts of calcium silicate, 40 parts of modified calcium carbonate, 16 parts of oil-soluble resin (8 parts of C5 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 production filter aid.

[0040] The modified calcium carbonate is prepared as follows: 40 parts by weight of commercially available calcium carbonate are pretreated (cleaned with acetone, dried and ground), then added to a mixture of 150 parts of anhydrous ethanol and 150 parts of deionized water and stirred to obtain a slurry; 2 parts of vinyltrimethoxysilane are added for a coupling reaction; the pH is adjusted to 8.4, nitrogen is passed through the mixture for deoxygenation for 30 minutes, the mixture is stirred at 160 r / min at a temperature of 60° C. for 4 hours, filtered, washed with ethanol, and dried to obtain an intermediate product; 40 parts of the intermediate product are added to 300 parts of deionized water, 1 part of acrylamide and 1 part of 2-acrylamido-2-methylpropanesulfonic acid are added for a modification reaction, the pH is adjusted to neutral, the mixture is heated to 26° C., 0.1 part of ammonium persulfate is added for a reaction for 3 hours, the mixture is heated to 48° C. and kept warm for 4 hours, centrifuged, washed with water, and dried to obtain the modified calcium carbonate.

[0041] The modified rosin resin is prepared by mixing 30 parts by weight of rosin, 90 parts of fumaric acid, and 6 parts of deionized water for an addition reaction. The mixture is first melted at 80° C. under nitrogen protection, and then heated to 160° C. with stirring for a heating reaction for 3 hours. After the reaction is completed, 8 parts of pentaerythritol, 0.2 parts of zinc oxide, and 0.1 parts of lithium hydroxide are added for a condensation reaction. The mixture is polycondensed at 200° C. for 120 minutes, cooled to room temperature, and discharged to obtain the modified rosin resin.

[0042] The preparation steps of the calcium silicate include: adding 60 parts by weight of fly ash to 180 parts of a sodium hydroxide solution with a mass concentration of 8%, stirring at 80° C. for 4 hours, filtering to obtain a filtrate, mixing the filtrate with a saturated calcium hydroxide aqueous solution, reacting at 60° C. for 6 hours, filtering after the reaction is completed to obtain a filter cake, adjusting the pH of the filter cake to 10, washing with water, and drying to obtain the calcium silicate.

[0043] Example 3 This embodiment provides a preparation process for an oil and gas production filter aid, comprising the following steps: S1: In parts by weight, 25 parts of soluble starch were added to 245 parts of deionized water, and the mixture was stirred to dissolve. Then, 18 parts of butyl methacrylate, 1.0 part of N,N-methylenebisacrylamide, 1.0 part of divinylbenzene, 0.5 part of cerium nitrate and 0.5 part of azobisisobutyronitrile were added, and the mixture was heated to react. The mixture was stirred at 90 r / min for 55 minutes, and then the temperature was raised to 68°C and the mixture was kept at this temperature for 5 hours. The mixture was washed with methanol, filtered and dried to obtain a double-absorption resin. S2: In parts by weight, 65 parts of calcium silicate, 45 parts of modified calcium carbonate, 18 parts of oil-soluble resin (10 parts of C5 petroleum resin and 8 parts of modified rosin resin) and 9 parts of the double-absorption resin are mixed to obtain an oil and gas production filter aid.

[0044] Preparation of the modified calcium carbonate: 45 parts by weight of commercially available calcium carbonate are pretreated (washed with acetone, dried and ground), then added to a mixture of 155 parts of anhydrous ethanol and 155 parts of deionized water and stirred to obtain a slurry, then 3 parts of vinyltrimethoxysilane are added for a coupling reaction, the pH is adjusted to 8.6, nitrogen is passed through to deoxygenate for 35 minutes, and the mixture is stirred at 180 r / min at a temperature of 65° C. for 3 hours, filtered, washed with ethanol, and dried to obtain an intermediate product; 45 parts of the intermediate product are added to 330 parts of deionized water, and then 1.4 parts of acrylamide and 1.4 parts of 2-acrylamido-2-methylpropanesulfonic acid are added for a modification reaction, the pH is adjusted to neutral, the temperature is raised to 28° C., 0.2 parts of ammonium persulfate are added for a reaction for 2 hours, and then the temperature is raised to 49° C. and kept for 3.5 hours, centrifuged, washed with water, and dried to obtain the modified calcium carbonate.

[0045] The modified rosin resin is prepared by mixing 35 parts of rosin, 95 parts of fumaric acid, and 8 parts of deionized water, by weight, for an addition reaction. The mixture is first melted at 84° C. under nitrogen protection, then heated to 168° C. with stirring for a heating reaction for 2.4 hours. After the reaction is completed, 10 parts of pentaerythritol, 0.3 parts of zinc oxide, and 0.16 parts of lithium hydroxide are added for a condensation reaction. The mixture is polycondensed at 204° C. for 110 minutes, cooled to room temperature, and discharged to obtain the modified rosin resin.

[0046] The preparation steps of the calcium silicate include: adding 65 parts by weight of fly ash to 190 parts by weight of a sodium hydroxide solution with a mass concentration of 9%, stirring at 85° C. for 3 hours, filtering to obtain a filtrate, mixing the filtrate with a saturated calcium hydroxide aqueous solution, reacting at 65° C. for 5 hours, filtering after the reaction is completed to obtain a filter cake, adjusting the pH of the filter cake to 10.5, washing with water, and drying to obtain the calcium silicate.

[0047] Example 4 The difference between this embodiment and embodiment 1 is that commercially available calcium carbonate (model MP-Rh) is used instead of modified calcium carbonate.

[0048] Example 5 The difference between this embodiment and embodiment 1 is that commercially available rosin resin (article number HC3444) is used instead of modified rosin resin.

[0049] Comparative Example 1 The difference between this comparative example and Example 1 is that 8 parts of rubber powder (Article No. 5561254) and 2 parts of polyacrylic acid resin (Article No. P756765) are used to replace 10 parts of double-absorption resin.

[0050] Comparative Example 2 The difference between this 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.

[0051] Comparative Example 3 The difference between this 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.

[0052] Performance Testing The above examples and comparative examples were tested: (1) Preparation of base slurry: 400 mL deionized water + 0.42 g anhydrous sodium carbonate + 12 g bentonite for drilling fluid preparation.

[0053] (2) Preparation of sample slurry: base slurry + 5 wt% filter aid (prepared in the examples and comparative examples).

[0054] (3) Stir at high speed for 5 minutes, and test the API and HTHP (80°C, 3.5 MPa) filtration performance of the base slurry and sample slurry respectively. Refer to the specific contents of Chapter 7 of GB / T 16783.1-2014 Field testing of drilling fluids in the petroleum and natural gas industry Part 1: Water-based drilling fluids for filtration performance testing.

[0055] Table 1 Performance test results

[0056] The above performance test results show that Examples 1-3 have the best overall performance, with API values ​​of 6.1-6.4 mL and HTHP values ​​of 39.6-40.1 mL. This is mainly because the water- and oil-absorbing double-absorbent resins are prepared from soluble starch and butyl methacrylate, and are used in conjunction with calcium silicate, modified calcium carbonate, and a compounded oil-soluble resin (including modified rosin resin) to achieve good filtration loss performance.

[0057] Compared with Example 1, Example 4 uses commercial calcium carbonate (model MP-Rh) instead of modified calcium carbonate, and the API becomes larger and the HTHP increases; Compared with Example 1, Example 5 uses commercial rosin resin (article number HC3444) instead of modified rosin resin, and the API becomes larger and the HTHP increases; Compared with Example 1, Comparative Example 1 uses 8 parts of rubber powder (article number 5561254) and 2 parts of polyacrylic acid resin (article number P756765) instead of 10 parts of double-absorption resin, and the API becomes larger and the HTHP increases. P increases; compared with Example 1, the amount of C5 petroleum resin in the 20 parts of oil-soluble resin in Comparative Example 2 is changed to 18 parts, and the amount of modified rosin resin is changed to 2 parts. Since the amount of modified rosin resin is too small, the compounding effect is not good, the API becomes larger, and the HTHP increases; compared with Example 1, the amount of C5 petroleum resin in the 20 parts of oil-soluble resin in Comparative Example 3 is changed to 5 parts, and the amount of modified rosin resin is changed to 15 parts. Since the amount of modified rosin resin is too much, the compounding effect is not good, the API becomes larger, and the HTHP increases.

Claims

1. A process for preparing a filter aid for oil and gas production, characterized in that: The following steps are involved: S1: In parts by weight, 20-30 parts of soluble starch are added to 240-250 parts of deionized water, stirred and dissolved, and 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, mixed and heated to react to obtain a double-absorption resin; S2: In parts 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 double-absorption resin are mixed to obtain an oil and gas production filter aid.

2. The preparation process of a filter aid for oil and gas production according to claim 1, characterized in that: The temperature reaction conditions include: stirring at a speed of 80-100 r / min for 50-60 min, then heating to 66-70° C. and reacting at this temperature for 4-6 h, washing with methanol, filtering, and drying.

3. The preparation process of a filter aid for oil and gas production according to claim 1, characterized in that: The calcium carbonate is modified calcium carbonate; The preparation method of the modified calcium carbonate comprises: pretreating 40-50 parts of commercially available calcium carbonate by weight, adding the pretreatment to a mixture of 150-160 parts of anhydrous ethanol and 150-160 parts of deionized water, stirring to obtain a slurry, then adding 2-4 parts of vinyltrimethoxysilane to carry out 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 to carry out a modification reaction to obtain the modified calcium carbonate.

4. The preparation process of a filter aid for oil and gas production according to claim 3, characterized in that: The coupling reaction conditions include: adjusting the pH to 8.4-8.8, deoxygenating with nitrogen for 30-40 minutes, stirring at a temperature of 60-70° C. and a speed of 160-200 r / min for 2-4 hours, filtering, washing with ethanol, and drying.

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

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

1.

7. The process for preparing a filter aid for oil and gas production according to claim 6, wherein: The rosin resin modified rosin resin; The preparation method of the modified rosin resin comprises: mixing 30-40 parts of rosin, 90-100 parts of fumaric acid and 6-10 parts of deionized water, carrying out 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 to carry out a condensation reaction to obtain the modified rosin resin.

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

9. The process for preparing a filter aid for oil and gas production according to claim 1, wherein: The preparation steps of the calcium silicate include: adding 60-70 parts by weight of fly ash to 180-200 parts of a sodium hydroxide solution with a mass concentration of 8-10%, stirring at 80-90° C. for 2-4 hours, filtering to obtain a filtrate, mixing the filtrate with a saturated calcium hydroxide aqueous solution, reacting at 60-70° C. for 4-6 hours, filtering after the reaction is completed to obtain a filter cake, adjusting the pH of the filter cake to 10-11, washing with water, and drying to obtain the calcium silicate.

10. A filter aid for oil and gas production, characterized in that: Prepared according to the process according to any one of claims 1 to 9.

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