Rock debris scavenger, preparation method thereof and application of rock debris scavenger in oil-based drilling fluid

Abstract

The invention provides a rock debris scavenger, a preparation method thereof and application of the rock debris scavenger in oil-based drilling fluid. The preparation method comprises the following steps: adding an acrylate oil-soluble monomer, an amino adsorption functional monomer and an oil-soluble initiator into a solution system containing a nonionic surfactant and an anionic surfactant, and carrying out polymerization reaction to form a first system; adding a cross-linking agent into the first system for cross-linking reaction to form a second system containing a polymer; and adding an oil phase solvent into the second system for extraction to obtain the rock debris scavenger. The rock debris scavenger can effectively remove rock debris in the oil-based drilling fluid.

Description

Technical Field

[0001] The invention relates to a rock cuttings remover and a preparation method thereof and application of the rock cuttings remover in oil-based drilling fluid, belonging to the field of petrochemical industry. Background Art

[0002] Oil-based drilling fluid is an oil-in-water emulsion system with oil as the external phase. It has excellent performance in stabilizing the wellbore, lubricating and resisting salt water pollution. It has become the preferred key technology to support safe and efficient drilling in complex formations, and is of great significance to supporting the steady increase of oil and gas reserves and production. However, during the drilling process, the rock cuttings produced by the formation breakage are repeatedly ground at the bottom of the well, and the particle size is greatly reduced to submicron size. After entering the oil-based drilling fluid, it is difficult to remove it through solid control equipment, resulting in a gradual increase in its content. When the content of fine rock cuttings increases, the strength of the framework structure formed by organic soil and water phase particles in the oil-based drilling fluid will be further strengthened, resulting in a significant increase in the viscosity and shear of the drilling fluid, hindering rapid drilling. At the same time, due to the high viscosity and shear, it is easy to generate excitation pressure and thus make the wellbore unstable. In addition, a high content of fine rock cuttings will also lead to problems such as virtual thickness of the mud cake, which will adhere to the drill, adsorb non-ionic surfactants, and cause poor emulsification stability of the system. When the content of rock cuttings is too high, the performance of the oil-based drilling fluid is seriously deteriorated, and it is difficult to reuse it. It has to be disposed of, further increasing the application cost of the oil-based drilling fluid and the risk of environmental pollution.

[0003] CN113292731A discloses a flocculant for removing rock cuttings from oil-based drilling fluids, which is prepared by grafting reaction of two prepolymers, one of which is a copolymer of hydrophilic monomers, cationic monomers and glycidyl methacrylate, and the other prepolymer is a copolymer of oil-soluble monomers, acrylamide and 2-mercaptoethylamine hydrochloride. The flocculant can selectively flocculate rock cuttings in oil-based drilling fluids, and further remove them in combination with solid control equipment. However, the flocculant has limited temperature resistance and is difficult to meet the application requirements of ultra-deep and high-temperature wells. In addition, the flocculation effect of the prepared product is poor. CN114605582A discloses a high-temperature resistant oil-based drilling fluid flocculant, which is prepared by copolymerizing styrene, methacrylate, fatty acid and para-hydroxystyrene using an emulsion polymer method. The flocculant improves the temperature resistance of the flocculant by steric hindrance of the benzene ring and inhibition of the acrylic acid water base by fatty acids, but the flocculation effect is limited.

[0004] Therefore, there is an urgent need to develop a high-temperature resistant high molecular weight polymer remover for selective removal of cuttings from oil-based drilling fluids. Summary of the invention

[0005] In order to solve the above technical problems, the object of the present invention is to provide a cuttings remover and a preparation method thereof and an application thereof in oil-based drilling fluid, wherein the cuttings remover can effectively remove cuttings in the oil-based drilling fluid.

[0006] To achieve the above object, the present invention provides a method for preparing a cuttings remover, which comprises:

[0007] Adding an acrylate oil-soluble monomer, an amine adsorption functional monomer, and an oil-soluble initiator to a solution system containing a nonionic surfactant and an anionic surfactant to carry out a polymerization reaction to form a first system;

[0008] adding a crosslinking agent to the first system to carry out a crosslinking reaction to form a second system containing a polymer;

[0009] An oil phase solvent is added to the second system for extraction to obtain a rock chip remover (after extraction, the oil phase system is the rock chip remover, which includes the oil phase solvent and the polymer dissolved in the oil phase solvent).

[0010] The weight ratio of the amino adsorption functional monomer to the acrylic ester oil-soluble monomer is 1:5-7; the weight of the crosslinking agent accounts for 2.0-4.5% of the total weight of the acrylic ester oil-soluble monomer and the amino adsorption functional monomer.

[0011] First, the present invention uses oil-soluble monomers and amino-based adsorption functional monomers as raw materials to polymerize first and then crosslink under the action of a crosslinking agent, so as to obtain a high molecular weight polymer with good temperature resistance. The high molecular weight polymer prepared in this way can be used as a component of a rock cuttings remover to selectively coat the fine rock cuttings in the oil-based drilling fluid, thereby agglomerating the fine rock cuttings to greatly increase their particle size to form larger aggregates, and then subsequently through simple screening, centrifugation and other solid control equipment to achieve rock cutting removal. Moreover, the molecular size of the high molecular weight polymer prepared in this way is relatively large in the liquid phase, which is conducive to adsorbing more solid phases and then agglomerating, thereby improving the removal effect of fine rock cuttings.

[0012] At the same time, the cuttings remover has no effect on removing useful solid phases such as barite and organic soil in oil-based drilling fluids, so it can meet the application requirements in high-density oil-based drilling fluids in the future. The content of polar groups such as hydroxyl groups on the surface of barite is relatively low, and it is difficult to form a strong adsorption effect with the groups in the above-mentioned high molecular weight polymers (such as amine groups), so it is difficult for flocculants to adsorb on the surface of barite; during the preparation process of organic soil, the surface has been intercalated and adsorbed by quaternary ammonium salt surfactants, and there are very few active bases on the surface for adsorption, so the above-mentioned remover is also difficult to adsorb organic soil.

[0013] Secondly, the present invention uses an oil phase solvent to extract the polymer prepared in the second system during the preparation process, thereby synergistically forming a rock cuttings remover as a component. The rock cuttings remover can then be quickly dissolved in the drilling fluid and produce the above-mentioned flocculation effect, thereby further improving the removal efficiency.

[0014] Furthermore, the acrylate oil-soluble monomer is selected from one or a combination of two or more of dodecyl (meth)acrylate, ethyl (meth)acrylate, tetradecyl (meth)acrylate, and hexadecyl (meth)acrylate.

[0015] Furthermore, the amino-based adsorption functional monomer is selected from one or a combination of two or more of dimethyldiallylammonium chloride, dimethylaminoethyl methacrylate and methacryloyloxyethyltrimethylammonium chloride.

[0016] Furthermore, the crosslinking agent is selected from one or a combination of two or more of polyethylene polyamine, N,N-methylenebisacrylamide and diaminodiphenyl sulfone. It is further preferred that the crosslinking agent is polyethylene polyamine, and it is more preferred that the polyethylene polyamine is selected from diethylene triamine and / or tetraethylene pentamine. Polyethylene polyamine, as a crosslinking agent, can undergo Michael addition reaction with multiple polymer terminal double bonds, which can play a crosslinking role on the one hand, thereby obtaining a high molecular weight polymer with greatly improved temperature resistance, so that the subsequent application requirements of deep wells and high temperature wells can be met; on the other hand, the introduced amine group can further enhance the adsorption stability of the polymer on the surface of the cuttings and improve the aforementioned flocculation effect.

[0017] Furthermore, the oil-soluble initiator is selected from one or a combination of two or more of azobisisobutyronitrile, dimethyl azobisisobutyrate and dibenzoyl peroxide.

[0018] Furthermore, the weight of the oil-soluble initiator accounts for 0.5-2.0% of the total weight of the acrylic acid ester oil-soluble monomer and the amino-based adsorption functional monomer.

[0019] Furthermore, the HLB value of the nonionic surfactant is between 8 and 18; preferably, the nonionic surfactant is selected from one or a combination of two or more of OP-10, Tween-60 and fatty alcohol polyoxyethylene ether.

[0020] Preferably, the weight of the nonionic surfactant accounts for 13.0-26.1% of the total weight of the acrylic acid ester oil-soluble monomer and the amino-based adsorption functional monomer.

[0021] Furthermore, the anionic surfactant is selected from one or a combination of two or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and sodium tetradecyl sulfonate.

[0022] Preferably, the weight of the anionic surfactant accounts for 8.5-17.5% of the total weight of the acrylic acid ester oil-soluble monomer and the amine-based adsorption functional monomer.

[0023] Furthermore, the polymerization reaction is carried out at a temperature of 70 to 80° C. and for a time of 3 to 5 hours.

[0024] Furthermore, the treatment temperature of the cross-linking reaction is 70-80° C. and the treatment time is 2-4 hours.

[0025] Further, an oil phase solvent is added to the second system and allowed to stand to extract the polymer in the second system. The standing time is 2 to 4 hours.

[0026] Furthermore, the weight average molecular weight of the polymer prepared in the second system is between 9 million and 15 million.

[0027] Furthermore, the oil phase solvent is white oil, more preferably white oil No. 3 and / or white oil No. 5. Furthermore, the volume amount of the oil phase solvent is 1 to 3 mL per gram of the weight of the polymer.

[0028] The present invention also provides a rock cuttings remover, which is prepared by the above-mentioned method for preparing the rock cuttings remover.

[0029] Based on the above reasons, the cuttings remover of the present invention has excellent removal efficiency for fine cuttings in oil-based drilling fluids and has good temperature resistance.

[0030] The present invention also provides a use of the aforementioned rock cuttings remover in oil-based drilling fluid.

[0031] Based on the above reasons, the cuttings remover of the present invention has high removal efficiency and good high temperature resistance when used to remove fine cuttings in oil-based drilling fluid, and is particularly suitable for selectively removing fine cuttings in oil-based drilling fluid under high temperature conditions (e.g., 180-220°C). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The microscopic morphology of rock cuttings in No. 3 white oil is shown when no rock cutting remover is added;

[0033] Figure 2 The microscopic morphology of rock chips in No. 3 white oil is shown when 0.1% rock chip remover is added;

[0034] Figure 3 The microscopic morphology of rock chips in No. 3 white oil is shown when 0.3% rock chip remover is added;

[0035] Figure 4 The test graphs of the suspension stability of organic soil in white oil are shown when no rock chip remover is added, 0.1% and 0.3% rock chip remover is added;

[0036] Figure 5 The test graphs of suspension stability of rock cuttings in white oil are shown when no rock cutting remover is added, 0.1% and 0.3% rock cutting remover is added;

[0037] Figure 6The graph shows the test of the suspension stability of barite in white oil when no rock chip remover is added, 0.1% and 0.3% rock chip remover are added. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0039] Example 1

[0040] This embodiment provides a method for preparing a rock cuttings remover, which comprises the following steps:

[0041] Step (1) adding 3 g OP-10 and 2 g sodium dodecylbenzene sulfonate to 100 mL deionized water and stirring until dissolved to obtain a solution system;

[0042] Step (2) 15 g of dodecyl (meth)acrylate, 5 g of ethyl (meth)acrylate, and 3 g of dimethyldiallylammonium chloride were added to the above solution system, and stirred at 100 r / min for 20 min. Nitrogen was introduced during the stirring process, and the heating temperature was set to 70° C.;

[0043] Step (3) When the temperature rises to 70° C., add 1 wt % of azobisisobutyronitrile by the total weight of the monomers (i.e., the weight of dodecyl (meth)acrylate + the weight of ethyl (meth)acrylate + the weight of dimethyldiallylammonium chloride), start condensing water, and carry out polymerization reaction under stirring for 3 hours to form a first system;

[0044] Step (4) adding 0.5 g of diethylenetriamine dropwise into the first system using a separatory funnel, and continuing the crosslinking reaction at 70° C. for 2 h to form a second system (containing a polymer);

[0045] After the reaction in step (5) is completed, 50 mL of No. 3 white oil is added to the second system, and the mixture is stirred and mixed at 200 r / min for 30 min. After the stirring and mixing is completed, the mixture is allowed to stand for 4 h, and the upper brown-yellow liquid phase is recovered as the reaction product, the rock chip remover.

[0046] Example 2

[0047] The only difference from Example 1 is that the amount of OP-10 used is 6 g; the amount of sodium dodecylbenzenesulfonate used is 4 g.

[0048] Example 3

[0049] The only difference from Example 1 is that the amount of dodecyl (meth)acrylate used is 20 g; the amount of ethyl (meth)acrylate used is 8 g; and the amount of dimethyldiallylammonium chloride used is 5 g.

[0050] Example 4

[0051] The only difference from Example 1 is that the polymerization reaction temperature in step (3) is 80°C.

[0052] Example 5

[0053] The only difference from Example 1 is that the amount of diethylenetriamine used is 1 g.

[0054] Example 6

[0055] The only difference from Example 1 is that the polymerization reaction temperature in step (3) is 5h.

[0056] Example 7

[0057] The only difference from Example 1 is that the cross-linking reaction time in step (4) is 4 hours.

[0058] Example 8

[0059] The only difference from Example 1 is that an equal volume of No. 3 white oil is replaced by No. 5 white oil.

[0060] Example 9

[0061] The only difference from Example 1 is that the standing time in step (5) is 2 h.

[0062] Example 10

[0063] The only difference from Example 1 is that in step (4), an equal amount of diethylenetriamine is replaced by N,N-dimethylacrylamide.

[0064] Comparative Example 1

[0065] This comparative example provides a method for preparing a rock cuttings remover, which comprises the following steps:

[0066] (1) Add 3 g OP-10 and 2 g sodium dodecylbenzene sulfonate to 100 mL deionized water and stir until dissolved to obtain a solution system;

[0067] (2) Add 15 g of dodecyl (meth)acrylate, 5 g of ethyl (meth)acrylate, and 3 g of dimethyldiallylammonium chloride to the above solution system, and stir at 100 r / min for 20 min. During the stirring process, nitrogen is introduced, and the heating temperature is set to 70°C;

[0068] (3) When the temperature rises to 70° C., add 1 wt % of azobisisobutyronitrile by the total weight of the monomers (i.e., the weight of dodecyl (meth)acrylate + the weight of ethyl (meth)acrylate + the weight of dimethyldiallylammonium chloride), start condensing water, and carry out polymerization reaction under stirring for 5 hours to obtain a reaction product system (containing a polymer);

[0069] (4) After the reaction is completed, add 50 mL of No. 3 white oil to the above reaction solution. Stir at 200 r / min for 30 min. After stirring, let stand for 4 h, and recover the upper brown-yellow liquid phase, which is the reaction product, the rock chip remover.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing a rock cuttings remover, which comprises the following steps:

[0072] (1) Add 3 g OP-10 and 2 g sodium dodecylbenzene sulfonate to 100 mL deionized water and stir until dissolved to obtain a solution system;

[0073] (2) Add 15 g of dodecyl (meth)acrylate, 5 g of ethyl (meth)acrylate, and 3 g of dimethyldiallylammonium chloride to the above solution system, and stir at 100 r / min for 20 min. During the stirring process, nitrogen is introduced, and the heating temperature is set to 70°C;

[0074] (3) When the temperature rises to 70° C., add 1 wt % of azobisisobutyronitrile by the total weight of the monomers (i.e., the weight of dodecyl (meth)acrylate + the weight of ethyl (meth)acrylate + the weight of dimethyldiallylammonium chloride), start condensing water, and carry out polymerization reaction under stirring for 3 h;

[0075] (4) 0.5 g of N,N-methylenebisacrylamide was added dropwise into the reaction solution using a separatory funnel, and the reaction was continued at 70° C. for 2 h to obtain a reaction product, a rock chip remover.

[0076] Comparative Example 3

[0077] This comparative example provides a method for preparing a rock cuttings remover, which comprises the following steps:

[0078] (1) Add 3 g OP-10 and 2 g sodium dodecylbenzene sulfonate to 100 mL deionized water and stir until dissolved to obtain a solution system;

[0079] (2) Add 15 g of dodecyl (meth)acrylate, 5 g of ethyl (meth)acrylate, and 3 g of polyethylene glycol monomethacrylate to the above solution system, and stir at 100 r / min for 20 min. During the stirring process, nitrogen is introduced, and the heating temperature is set to 70°C;

[0080] (3) When the temperature rises to 70° C., add 1 wt % of azobisisobutyronitrile by the total weight of the monomers (i.e., the weight of dodecyl (meth)acrylate + the weight of ethyl acrylate + the weight of poly(ethylene glycol) methacrylate), start condensing water, and carry out polymerization reaction for 3 h under stirring;

[0081] (4) adding 0.5 g of N,N-methylenebisacrylamide dropwise into the above reaction solution using a separatory funnel, and continuing the cross-linking reaction at 70° C. for 2 h to obtain a product system;

[0082] (5) After the reaction is completed, add 50 mL of No. 3 white oil to the above reaction solution. Stir at 200 r / min for 30 min. After stirring, let it stand for 4 h, and recover the upper brown-yellow liquid phase, which is the reaction product, the rock chip remover.

[0083] Evaluation of test results

[0084] (i) The weight average molecular weight of the polymers prepared in the examples and comparative examples was tested using a multi-angle laser light scattering instrument (Brookhaven). The test results are shown in Table 1.

[0085] (ii) Since rock cuttings belong to the low-density solid phase in the drilling fluid and have the highest content, the change in the low-density solid phase content is used to evaluate the effect of rock cuttings removal.

[0086] The oil-based drilling fluid was prepared according to the following formula: white oil as the oil phase; and based on the oil phase as 100%, 2wt% of the main lactic acid amide + 2wt% of the secondary lactic acid alkanolamide + 1wt% of the organic soil + 2.5wt% of the filtrate reducer modified asphalt + 1wt% of the calcium oxide; and calcium chloride aqueous solution (mass concentration 20wt%) as the water phase, the volume ratio of white oil to calcium chloride aqueous solution is 8:2; and barite, the amount of barite is to adjust the density of the drilling fluid to 1.8g / cm 3 .

[0087] Add 20% (the weight fraction of the oil-based drilling fluid as 100%) of fine rock cuttings (screened with 200 mesh, with a particle size of less than 75 μm) to the above oil-based drilling fluid, and stir at a high speed of 10000 r / min for 40 minutes. Then test the low-density solid content (LGS) in the oil-based drilling fluid according to GBT16783.2. After testing, its LGS is 10.5%. Continue to add 1% (the mass fraction of the scavenger as 100% of the oil-based drilling fluid) of the scavenger in the embodiment and the comparative example, and stir at 200 r / min for 30 minutes. After stirring, heat to 60°C and pass through a 200-mesh standard sieve, and test the LGS2 of the liquid phase after sieving.

[0088] At the same time, in order to evaluate the temperature resistance of the scavenger, a parallel group experiment was set up, and the drilling fluid with the scavenger was hot rolled in a roller furnace at 180℃ for 16 hours (aging treatment). After being taken out and cooled to 60℃, it was passed through a 200-mesh standard sieve, and the LGS2 of the liquid phase after the sieve was tested.

[0089] The low-density solid content removal rate was tested according to the following formula: removal rate = (LGS-LGS2) / LGS×100%; wherein LGS is 10.5%.

[0090] The test results are shown in Table 1.

[0091] (III) The viscosity of the oil-based drilling fluid was tested according to the method in GBT 16783.2, with the viscometer rotating at 600 rpm. The test results are shown in Table 1.

[0092] Table 1

[0093]

[0094] It can be found from Table 1 that, compared with Comparative Examples 1-3, Examples 1-10 of the present invention exhibited more significant rock debris removal effects before and after high-temperature aging.

[0095] Compared with Example 1, no crosslinking agent was added in Comparative Example 1, so that the molecular weight of the prepared scavenger was relatively low, and the adsorption effect on the cuttings was relatively weak, and thus the flocculation effect before aging was significantly weakened. In addition, because it was not crosslinked, the high temperature resistance of the polymer was poor, so after high temperature aging, the effect of agglomerating cuttings was basically lost.

[0096] Compared with Example 1, Comparative Example 2 did not use oil solvent to extract the cuttings remover, resulting in the cuttings remover existing in the aqueous phase in the form of curled microspheres. When added to the oil-based drilling fluid, the remover dissolved very slowly in the oil phase of the oil-based drilling fluid, so the effect of agglomerating cuttings was extremely poor.

[0097] Compared with Example 1, the adsorption monomer is replaced by hydrogen bond adsorption monomer from amine group in Comparative Example 3. Since the hydrogen bond adsorption effect is very weak compared with the electrostatic effect, the rock cuttings agglomeration effect is significantly reduced.

[0098] It can be found from Table 1 that the weight average molecular weight of the polymers in Examples 1 to 10 is between 600×10 4 Da, the polymer molecular weight is relatively high.

[0099] Furthermore, compared with Example 1, Example 2 increases the amount of nonionic surfactant added, which greatly increases the number of micelles in the solution during the preparation process and reduces the amount of monomers in a single micelle. Since an oil-soluble initiator is used, the reduction in the amount of monomers in the micelle is not conducive to further increasing the molecular weight of the polymer. Therefore, the molecular weight of the polymer decreases slightly and the rock debris removal effect is slightly weakened.

[0100] Furthermore, compared with Example 1, Example 3 increases the amount of monomer added to increase the amount of monomer in a single micelle, thereby further increasing the reaction rate in the emulsion polymerization reaction, generating more heat, and overheating of the reaction easily leads to the generation of polymer branches, which is also not conducive to the increase of molecular weight. Therefore, the molecular weight of the polymer prepared in Example 3 is slightly reduced, and the rock debris removal effect is slightly weakened.

[0101] Furthermore, compared with Example 1, Example 4 increases the polymerization temperature. According to the law of emulsion polymerization, increasing the reaction temperature accelerates the decomposition of the initiator and easily forms multiple polymerization active points, thereby causing the molecular weight of the polymer prepared in Example 4 to decrease.

[0102] Furthermore, compared with Example 1, Example 5 increases the amount of crosslinking agent, and the molecular weight of the prepared polymer is improved. However, the rock cuttings removal effect of Example 5 is slightly reduced compared with Example 1. This is because the increase in the amount of crosslinking agent can increase the molecular weight, but at the same time has a certain negative effect on the solubility of the polymer, slightly reducing its effect of agglomerating rock cuttings.

[0103] Furthermore, compared with Example 1, the polymerization time of the polymer in Example 6 before adding the crosslinking agent is prolonged, which reduces the remaining amount of the active component of the initiator, thereby reducing the chance of the crosslinking agent generating active points, so the crosslinking effect is weaker, resulting in a slight decrease in the molecular weight of the polymer.

[0104] Furthermore, compared with Example 1, the reaction time after the addition of the cross-linking agent in Example 7 is prolonged, which is conducive to fully exerting the cross-linking effect and increasing the molecular weight. However, the excessively high molecular weight further affects the solubility of the cuttings remover in the oil phase, thereby weakening the cuttings removal effect.

[0105] Furthermore, compared with Example 1, Example 8 replaces the extraction solvent with No. 5 white oil with higher viscosity, thereby restricting the dissolution rate of the scavenger polymer in the oil phase, so that the rock debris removal effect is slightly weakened.

[0106] Furthermore, compared with Example 1, Example 9 reduces the standing time after extraction, so that a small amount of water remains in the upper oil phase, thereby slightly weakening the rock debris removal effect.

[0107] Furthermore, compared with Example 1, the crosslinking agent of Example 10 is replaced by N,N-dimethylbisacrylamide from diethylenetriamine, and the polymer is also crosslinked, and the molecular weight is increased. However, the polymer using diethylenetriamine has a stronger adsorption capacity, so the flocculation effect of Example 1 is better than that of Example 10.

[0108] (IV) Morphology evaluation

[0109] Sample preparation:

[0110] Group 1: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) were added to 100 mL of No. 3 white oil, without adding a rock chip remover.

[0111] The second group: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) and 0.1 g of the rock chip remover of Example 1 were added to 100 mL of No. 3 white oil.

[0112] The third group: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) and 0.3 g of the rock chip remover of Example 1 were added to 100 mL of No. 3 white oil.

[0113] Figure 1 The figure shows the microscopic morphology of fine rock chips in No. 3 white oil when no rock chip remover is added.

[0114] Figure 2 The microscopic morphology of fine rock chips in No. 3 white oil is shown when 0.1% (0.1 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added.

[0115] Figure 3 The microscopic morphology of fine rock chips in No. 3 white oil is shown when 0.3% (0.3 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added.

[0116] Generally, the color of oil-based drilling fluid is too dark, and the material morphology cannot be photographed with a microscope using oil-based drilling fluid as the medium. However, the main component of oil-based drilling fluid is white oil, so white oil is used as the medium for morphology observation here. Figure 1 It can be seen that before adding the rock chip remover, the rock chips were evenly dispersed in the No. 3 white oil at a submicron scale. Figure 2 It can be seen that after adding 0.1% rock chip remover, the fine rock chips are significantly aggregated, showing an ellipsoidal spherical shape, tightly packed, and the size is about 50-60μm. Different aggregates are adhered to each other, but the contact area is small, and there is a certain aggregation tendency. Figure 3 It can be seen that after adding 0.3% of rock debris remover, the size of the agglomerates increased significantly, showing that small agglomerates aggregated with each other to form large-sized agglomerates.

[0117] (V) Selective evaluation

[0118] Sample preparation:

[0119] Group 1: 10 g of organic soil was added to 100 mL of No. 3 white oil, and no rock debris remover was added.

[0120] Group 2: 10 g of organic soil and 0.1 g of the rock debris remover of Example 1 were added to 100 mL of No. 3 white oil.

[0121] The third group: 10 g of organic soil and 0.3 g of the rock debris remover of Example 1 were added to 100 mL of No. 3 white oil.

[0122] Group 4: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) were added to 100 mL of No. 3 white oil, without adding a rock chip remover.

[0123] Group 5: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) and 0.1 g of the rock chip remover of Example 1 were added to 100 mL of No. 3 white oil.

[0124] Group 6: 10 g of fine rock chips (screened with 200 mesh, with a particle size of less than 75 μm) and 0.3 g of the rock chip remover of Example 1 were added to 100 mL of No. 3 white oil.

[0125] Group 7: 10 g of barite was added to 100 mL of No. 3 white oil, and no rock chip remover was added.

[0126] Group 8: 10 g of barite and 0.1 g of the rock cuttings remover of Example 1 were added to 100 mL of No. 3 white oil.

[0127] Group 9: 10 g of barite and 0.3 g of the rock cuttings remover of Example 1 were added to 100 mL of No. 3 white oil.

[0128] Figure 4 The test graphs of the suspension stability of organic soil in white oil are shown when no rock chip remover is added, 0.1% (0.1 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added, and 0.3% (0.3 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added.

[0129] Figure 5 The test graphs of suspension stability of rock chips (harmful solid phase) in white oil are shown when no rock chip remover is added, 0.1% (0.1 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added, and 0.3% (0.3 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added.

[0130] Figure 6 The test graphs of the suspension stability of barite in white oil are shown when no rock chip remover is added, 0.1% (0.1 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added, and 0.3% (0.3 g of rock chip remover is added to 100 mL of No. 3 white oil) of the rock chip remover of Example 1 is added.

[0131] pass Figure 4-Figure 6It can be found that the above-mentioned rock cuttings remover of the present invention can aggregate the rock cuttings and increase their size, thereby accelerating their sedimentation rate, causing the rock cuttings to settle and the upper liquid phase to clarify. However, no significant sedimentation of organic soil and barite occurs, indicating that the remover has basically no agglomeration effect on the useful solid phase organic soil and barite, and has good selectivity for rock cuttings.

Claims

1. A method for preparing a rock cuttings remover, wherein: include: Adding an acrylate oil-soluble monomer, an amine adsorption functional monomer, and an oil-soluble initiator to a solution system containing a nonionic surfactant and an anionic surfactant to carry out a polymerization reaction to form a first system; Adding a crosslinking agent to the first system to carry out a crosslinking reaction to form a second system containing a polymer; adding an oil phase solvent to the second system for extraction to obtain the rock cuttings remover; The weight ratio of the amino-based adsorption functional monomer to the acrylic ester oil-soluble monomer is 1:5-7; the weight of the cross-linking agent accounts for 2.0-4.5% of the total weight of the acrylic ester oil-soluble monomer and the amino-based adsorption functional monomer.

2. The method for preparing a rock chip remover according to claim 1, wherein: The amino-based adsorption functional monomer is selected from one or a combination of two or more of dimethyldiallylammonium chloride, dimethylaminoethyl methacrylate and methacryloyloxyethyltrimethylammonium chloride.

3. The method for preparing a rock chip remover according to claim 1, wherein: The crosslinking agent is selected from one or a combination of two or more of polyethylene polyamine, N,N-methylenebisacrylamide and diaminodiphenyl sulfone.

4. The method for preparing a rock chip remover according to claim 1, wherein: The acrylic acid ester oil-soluble monomer is selected from one or a combination of two or more of dodecyl (meth)acrylate, ethyl (meth)acrylate, tetradecyl (meth)acrylate and hexadecyl (meth)acrylate.

5. The method for preparing a rock cuttings remover according to claim 1, wherein: The oil-soluble initiator is selected from one or a combination of two or more of azobisisobutyronitrile, dimethyl azobisisobutyrate and dibenzoyl peroxide; The weight of the oil-soluble initiator accounts for 0.5-2.0% of the total weight of the acrylic acid ester oil-soluble monomer and the amino-based adsorption functional monomer.

6. The method for preparing a rock cuttings remover according to claim 1, wherein: The HLB value of the nonionic surfactant is between 8 and 18; The weight of the nonionic surfactant accounts for 13.0-26.1% of the total weight of the acrylic acid ester oil-soluble monomer and the amino-based adsorption functional monomer.

7. The method for preparing a rock cuttings remover according to claim 1, wherein: The oil phase solvent is white oil.

8. The method for preparing a rock cuttings remover according to claim 1, wherein: The polymerization reaction is carried out at a temperature of 70 to 80° C. and for a time of 3 to 5 hours. The processing temperature of the cross-linking reaction is 70-80° C. and the processing time is 2-4 hours.

9. A rock chip remover, wherein: The cuttings remover is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the cuttings remover according to claim 9 in oil-based drilling fluid.

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