Rheological response cross-linked resin plugging slurry as well as preparation method and application thereof

Abstract

The invention discloses rheological response cross-linked resin leaking stoppage slurry as well as a preparation method and application thereof. The leaking stoppage slurry comprises the following components in parts by volume: 20-75 parts of a base solution, 25-80 parts of a water-based emulsion, 0.2-1 part of a demulsifier, 0-5 parts of a retarder, 0.5-2 parts of a rheological modifier, 0-50 parts of a weighting material and 0.5-4 parts of a cross-linking agent, the water-based emulsion is selected from one or a combination of a water-based polyurethane emulsion and a water-based acrylate emulsion; the cross-linking agent can react with active groups in the water-based emulsion; the demulsifier is organic weak acid; the retarder can reduce the reaction rate of the water-based emulsion and the cross-linking agent; the rheology modifier is an organic weak acid sodium salt; the base fluid is polymer drilling fluid. The rheological response crosslinking resin is prepared by utilizing physical crosslinking after emulsion demulsification and chemical crosslinking between the main agent and the crosslinking agent, and the rheological response crosslinking resin is applied to water-based drilling fluid to successfully plug cracks, so that the requirements of on-site drilling plugging construction are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil drilling, and particularly relates to a rheological response cross-linked resin plugging slurry, a preparation method thereof, and an application thereof. Background Art

[0002] Compared with conventional oil wells, problems such as ultra-high temperature, alternating high and low pressure layers, and fracture-type severe leakage exist in ultra-deep wells, unconventional oil wells, and offshore oil wells, making them difficult to plug. In particular, severe leakage occurring in fractured formations has become a difficult problem in drilling and completion technology. In response to this problem, the current mainstream view is that polymer gel plugging materials have strong self-adaptive ability, strong viscous resistance and shear dilution resistance, and are not easily diluted and washed away in large fractures or karsts, making them more suitable for plugging operations in fractured leakage.

[0003] Currently, polymer plugging materials studied in the laboratory include polyacrylamide, polyethyleneimine, polyvinyl alcohol, phenolic resin, natural compounds, etc. These materials can achieve good plugging effects when used alone, but after being blended with drilling fluid, the regularity of the molecular chains of the plugging materials will be damaged, and the reactive groups will also lose their activity, resulting in the inability of the plugging materials to gel or solidify after being blended with the drilling fluid.

[0004] The development trends of gel resin materials at home and abroad mainly focus on the screening of cross-linking agents for polyacrylamide, the synthesis of main agents, epoxy modification, silica modification, and polyethyleneimine modification, etc. There is less research on other materials. It is undeniable that polyacrylamide has natural advantages such as simple operation and controllable gelation time as a drilling plugging resin, but it has high requirements for construction technology at high temperatures, the preparation process of chemical cross-linking agents is cumbersome, the preparation cost is high, and it also has disadvantages such as poor anti-pollution ability. Therefore, it cannot achieve the expected effect in actual applications. If a resin material with low viscosity, good anti-pollution ability, and controllable gelation time can be developed, this kind of problem will be effectively solved, creating a safe and efficient construction environment.

[0005] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] The object of the present invention is to provide a rheological response cross-linked resin plugging slurry, a preparation method thereof, and an application thereof, which solve the problems of high initial viscosity and poor pollution resistance of existing chemical gel plugging materials. A rheological response cross-linked resin is prepared by using physical cross-linking after emulsion demulsification and chemical cross-linking between the main agent and the cross-linking agent, and is applied to water-based drilling fluid to successfully plug fractures, meeting the needs of on-site drilling plugging construction.

[0007] To achieve the above object, the present invention provides a rheological response cross-linked resin plugging slurry, which comprises the following components in parts by volume: 20-75 parts of a base fluid, 25-80 parts of an aqueous emulsion, 0.2-1 part of a demulsifier, 0-5 parts of a retarder, 0.5-2 parts of a rheological modifier, 0-50 parts of a weighting material, and 0.5-4 parts of a cross-linking agent; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; wherein, the aqueous emulsion is any one or a combination of an anionic aqueous polyurethane resin and an anionic aqueous acrylate resin; the cross-linking agent is used to react with the active groups in the aqueous emulsion during use for chemical cross-linking, such as the nucleophilic ring-opening reaction between aziridine and carboxyl, or the ring-opening addition reaction between epoxy resin and carboxyl, or the condensation reaction between polyethyleneimine and amide group, etc.; the rheological modifier is an organic weak acid sodium salt; the demulsifier is an organic weak acid; the retarder is used to reduce the reaction rate between the aqueous emulsion and the cross-linking agent; and the base fluid is a water-based drilling fluid.

[0008] Preferably, the plugging slurry comprises the following components in parts by volume: 25-75 parts of a base fluid, 25-75 parts of an aqueous emulsion, 0.8-1 part of a demulsifier, 0.2-1 part of a retarder, 0.5-1 part of a rheological modifier, 5-40 parts of a weighting material, and 1-4 parts of a cross-linking agent are added to the base fluid; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts.

[0009] Preferably, the aqueous polyurethane emulsion is selected from anionic high-solids aqueous polyurethane; or / and, the aqueous acrylate emulsion is selected from anionic high-solids acrylate resin. Using anionic high-solids aqueous polyurethane or / and anionic high-solids acrylate resin, they have high active ingredients and can have good gelling effects at low dosages.

[0010] Preferably, the retarder is selected from any one or more of sodium chloride, fatty alcohol polyoxyethylene ether carboxylate, and fatty alcohol polyoxyethylene ether; or / and, the cross-linking agent is selected from any one or more of aziridine, polyethyleneimine, carbodiimide, hexamethylene diisocyanate, phenolic cross-linking agent, chromium acetate, polyetheramine, and water-based epoxy resin cross-linking agent; or / and, the demulsifier is selected from any one or more of n-octanoic acid, lauric acid, lauric diacid, hexanoic acid, stearic acid, and acetic acid; or / and, the rheological modifier is selected from any one or more of sodium lactate, sodium acetate, sodium citrate, and sodium ascorbate; or / and, the weighting material is selected from any one or more of calcium carbonate, barite, ultrafine iron powder, bluestone powder, and ilmenite.

[0011] Preferably, the lost circulation plugging slurry comprises the following components in parts by volume: 25-75 parts of base fluid, 25-75 parts of aqueous emulsion, 1 part of demulsifier, 0.2-0.5 part of retarder, 1 part of rheology modifier, 10 parts of weighting material, and 2-4 parts of crosslinking agent; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; wherein, the base fluid is polymer drilling fluid, the aqueous emulsion is anionic high-solid content aqueous polyurethane or anionic high-solid content acrylate resin, the demulsifier is lauric acid, the retarder is sodium laureth carboxylate, the rheology modifier is sodium acetate, the weighting material is barite, and the crosslinking agent is an aqueous epoxy resin crosslinking agent.

[0012] Preferably, the lost circulation plugging slurry comprises the following components in parts by volume: 50 parts of base fluid, 50 parts of aqueous emulsion, 1 part of demulsifier, 1 part of retarder, 1 part of rheology modifier, 40 parts of weighting material, and 1 part of crosslinking agent; wherein, the base fluid is polymer drilling fluid, the aqueous emulsion is anionic high-solid content acrylate resin, the demulsifier is lauric acid, the retarder is sodium chloride, the crosslinking agent is polyethyleneimine, the rheology modifier is sodium ascorbate, and the weighting material is barite.

[0013] Preferably, the lost circulation plugging slurry comprises the following components in parts by volume: 75 parts of base fluid, 25 parts of aqueous emulsion, 0.8 part of demulsifier, 0.5 part of retarder, 0.5 part of rheology modifier, 5 parts of weighting material, and 2 parts of crosslinking agent; wherein, the base fluid is polymer drilling fluid, the aqueous emulsion is anionic high-solid content acrylate resin, the demulsifier is dodecanedioic acid, the retarder is sodium laureth carboxylate, the crosslinking agent is aziridine crosslinking agent, the rheology modifier is sodium lactate, and the weighting material is ultrafine calcium carbonate.

[0014] Preferably, the polymer drilling fluid comprises: water, 4% bentonite, 0.6% potassium polyacrylate, 0.15% hydrolyzed acrylonitrile, 5% sulfonated asphalt, and 2% ultrafine calcium carbonate.

[0015] Another object of the present invention is to provide a preparation method of the rheology-responsive crosslinked resin lost circulation plugging slurry, which preparation method comprises: in parts by volume, adding 25-80 parts of aqueous emulsion, 0.2-1 part of demulsifier, 0-5 parts of retarder, 0.5-2 parts of rheology modifier into 20-75 parts of base fluid, stirring evenly, then adding 0-50 parts of weighting material and 0.5-3.5 parts of crosslinking agent, and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts, to obtain the lost circulation plugging slurry.

[0016] Another object of the present invention is to provide an application of the rheology-responsive crosslinked resin lost circulation plugging slurry in lost circulation plugging during drilling.

[0017] The rheological response crosslinked resin plugging slurry of the present invention, its preparation method and application solve the problems of high viscosity, poor temperature resistance and poor pollution resistance of existing chemical gel plugging materials, and have the following advantages: (1) By combining physical crosslinking and chemical crosslinking, the present invention realizes the rheological response characteristics of non-gelling during stirring and gelation under static conditions, and solves the problems of high viscosity and poor pollution resistance of existing chemical gel plugging materials. The present invention uses physical crosslinking after emulsion demulsification and chemical crosslinking between the main agent and the crosslinking agent to prepare a rheological response crosslinked resin, and applies it to water-based drilling fluids to successfully plug fractures, meeting the needs of on-site drilling plugging construction;

[0018] (2) The plugging agent of the present invention can be prepared with a variety of water-based emulsions on the market, has the rheological response characteristics of non-gelling during stirring and gelation under static conditions, and at the same time has excellent anti-pollution properties, can be compounded with water-based drilling fluids, and can effectively solve problems such as viscosity and anti-pollution properties; (3) For the plugging agent of the present invention, since the gelation principle of the rheological response crosslinked resin mainly comes from crosslinking rather than crystallization, the material itself has excellent anti-pollution properties, can be compounded with water-based drilling fluids, and meets the requirement of controllable gelation time at different temperature gradients; (4) For the plugging agent of the present invention, the emulsion slowly demulsifies under weak acid conditions, and before demulsification, the emulsion has good compatibility and fluidity with the drilling fluid, and has a lower consistency than traditional chemical plugging materials; the system quickly condenses into a weak gel through physical crosslinking under static conditions, effectively reducing the phenomenon of water flow diluting the plugging slurry; and then slowly condenses into a strong gel through chemical crosslinking to achieve the plugging of the drilling loss layer; (5) For the plugging agent of the present invention, materials such as polyurethane used have good temperature resistance, strength and toughness, and have excellent weather resistance and mechanical properties after gelation, and are applicable to a wide range of environments. Specific Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be noted that: for those not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0021] In the present invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0022] The features mentioned in the present invention can be combined arbitrarily as long as there is no contradiction in the combination of these features, and all possible combinations should be considered as being within the scope described in this specification. Each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equivalent or similar features.

[0023] The present invention provides a rheological response cross-linked resin plugging slurry, its preparation method and application. The plugging slurry comprises the following components in parts by volume: 20 - 75 parts of a base fluid, 25 - 80 parts of an aqueous emulsion, 0.2 - 1 part of a demulsifier, 0 - 5 parts of a retarder, 0 - 50 parts of a weighting material, 0.5 - 2 parts of a rheological regulator, and 0.5 - 3.5 parts of a cross-linking agent, and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; wherein, the aqueous emulsion is selected from one or a combination of an aqueous polyurethane emulsion and an aqueous acrylate emulsion, and these aqueous emulsions are all anionic emulsions; the cross-linking agent can react with the active groups in the aqueous emulsion; the demulsifier is an organic weak acid; the rheological regulator can avoid the occurrence of flocculation; the retarder can reduce the reaction rate between the aqueous emulsion and the cross-linking agent; and the base fluid is a polymer drilling fluid.

[0024] Based on the fact that the acidic material (i.e., the demulsifier in the present invention) will reduce the electrophoretic potential of the emulsion, lower the stability of the emulsion, cause the latex particles to attract each other and gradually increase in particle size. With the further destruction of stability, the attraction between the latex particles increases and finally an associated structure is formed. In this state, the force between the gels mainly comes from polar interactions and the entanglement of molecular chains, so it is physical cross-linking. According to this principle, the consistency can remain unchanged during the stirring process, and the consistency can increase rapidly under static conditions. At the same time, the associated structure can be destroyed by applying shear force, and physical cross-linking can be re-realized through self-healing under static conditions, and this reaction process is reversible. The ionization of the weak acid is relatively weak and the acidity is easy to control. Therefore, the rate of reduction of emulsion stability can be controlled by the weak acid, thereby further controlling the rate of physical cross-linking. After physical cross-linking, the cross-linking agent reacts with the reactive groups on the molecular chain of the aqueous emulsion, thereby further increasing the strength of the gel, which is chemical cross-linking, and this reaction is irreversible. Therefore, the present invention combines physical cross-linking and chemical cross-linking to achieve the rheological response characteristics of non-gelling during the stirring process and gel formation under static conditions.

[0025] For plugging slurries, their viscosity, pumpable time, and bearing strength after gelling are very important. In drilling plugging operations, it is necessary to ensure that the plugging material penetrates deep into the cracks to form a sealing plugging layer. However, if the viscosity of the plugging material is too high, the flow will be blocked, pumping will be difficult, and the operation risk will increase. Therefore, it is necessary to regulate the viscosity to balance the transportation and retention capabilities and maintain the stability of the plugging barrier. In addition, if the plugging material cannot be pumped and the slurry cures prematurely, it will cause plugging failure or blockage risk due to retention in the wellbore. Therefore, it is also necessary to accurately match the construction window period, and different pumpable times need to be designed according to the requirements of different wells, generally controlled above 180 minutes. For the bearing strength of the plugging material after gelling, it is necessary to ensure that if the final strength of the plugging slurry is insufficient, it is easily penetrated by the formation pressure, resulting in secondary leakage. It is necessary to optimize the strength to match the formation conditions to ensure that the strength of the plugging layer is sufficient to maintain the long-term plugging effect. The rheological response cross-linked resin plugging slurry of the present invention has significant advantages in terms of viscosity and pumpable time, and the bearing strength after gelling can meet the requirements without secondary leakage.

[0026] The plugging material of the present invention generates a gel by relying on the polarity between molecules and the synergistic effect of cross-linking reactions. The water-based drilling fluid has basically no effect on the gelling reaction and can gel after being blended with the drilling fluid in different proportions in the experimental examples, showing good anti-pollution performance.

[0027] The following will detail the rheological response cross-linked resin plugging slurry provided by the present invention, its preparation method, and applications through examples, comparative examples, and experimental examples.

[0028] In the following embodiments, unless otherwise specified, the base fluid is a polymer drilling fluid, and the formula is: water + 4% bentonite + 0.6% potassium polyacrylate + 0.15% ammonium salt of hydrolyzed polyacrylonitrile + 5% sulfonated asphalt + 2% ultra-fine calcium carbonate, and the values given in the formula are all mass fractions.

[0029] In the following embodiments, the high-solid polyurethane, high-solid acrylate resin, water-based epoxy resin, and polyacrylamide are all purchased products, and the manufacturers and trade names are shown in Table 1 below.

[0030] Table 1 Reagent Information Example 1 A rheological response cross-linked resin plugging slurry, and its preparation method includes: By volume, 75 parts of water-based emulsion, 1 part of demulsifier, 0.5 part of retarder, and 1 part of rheological regulator are added to 25 parts of base fluid, stirred evenly, and then 10 parts of weighting material and 2 parts of cross-linking agent are added to make plugging slurry A1.

[0031] The above base fluid is a polymer drilling fluid, the aqueous emulsion is a high-solid-content polyurethane, the demulsifier is lauric acid, the retarder is sodium fatty alcohol polyoxyethylene ether carboxylate, the crosslinking agent is an aqueous epoxy resin, the rheology regulator is sodium acetate, and the weighting material is barite.

[0032] For the rheology-responsive crosslinked resin plugging slurry prepared in this example, the performance test results of gel formation at reaction temperatures of 70 °C, 80 °C, and 90 °C are shown in Table 1.

[0033] Example 2 A rheology-responsive crosslinked resin plugging slurry is basically the same as that of Example 1, except that: By volume, 50 parts of an aqueous emulsion, 1 part of a demulsifier, 1 part of a retarder, and 1 part of a rheology regulator are added to 50 parts of the base fluid. After stirring evenly, 40 parts of a weighting material and 1 part of a crosslinking agent are added to prepare the plugging slurry A2; The retarder, crosslinking agent, and rheology regulator used are different from those of Example 1, where the retarder is sodium chloride, the crosslinking agent is polyethyleneimine, and the rheology regulator is sodium ascorbate.

[0034] For the rheology-responsive crosslinked resin plugging slurry prepared in this example, the performance test results of gel formation at a reaction temperature of 60 °C are shown in Table 1.

[0035] Example 3 A rheology-responsive crosslinked resin plugging slurry is basically the same as that of Example 1, except that: By volume, 25 parts of an aqueous emulsion, 0.8 part of a demulsifier, 0.5 part of a retarder, and 0.5 part of a rheology regulator are added to 75 parts of the base fluid. After stirring evenly, 5 parts of a weighting material and 2 parts of a crosslinking agent are added to prepare the plugging slurry A3; The aqueous emulsion, demulsifier, crosslinking agent, rheology regulator, and weighting material used are different from those of Example 1, where the aqueous emulsion is a high-solid-content acrylate resin, the demulsifier is sebacic acid, the crosslinking agent is an aziridine crosslinking agent, the rheology regulator is sodium lactate, and the weighting material is ultrafine calcium carbonate.

[0036] For the rheology-responsive crosslinked resin plugging slurry prepared in this example, the performance test results of gel formation at a reaction temperature of 40 °C are shown in Table 1.

[0037] Comparative Example 1 A rheology-responsive crosslinked resin plugging slurry is basically the same as that of Example 1, except that: The aqueous emulsion used is a high-solid-content acrylate resin.

[0038] The plugging slurry B1 prepared in this comparative example, and the performance test results of gel formation at a reaction temperature of 90 °C are shown in Table 1.

[0039] Comparative Example 2 A rheological response crosslinked resin plugging slurry is basically the same as Example 1, except that: The base liquid used is 50 parts, and the aqueous emulsion used is 50 parts.

[0040] The plugging slurry B2 prepared in this comparative example, and the performance test results of its gel formation at a reaction temperature of 90 °C are shown in Table 1.

[0041] Comparative Example 3 A rheological response crosslinked resin plugging slurry is basically the same as Example 1, except that: The base liquid used is 75 parts, and the aqueous emulsion used is 25 parts.

[0042] The plugging slurry B3 prepared in this comparative example, and the performance test results of its gel formation at a reaction temperature of 90 °C are shown in Table 1.

[0043] Comparative Example 4 A rheological response crosslinked resin plugging slurry is basically the same as Example 1, except that: The demulsifier used is 2 parts.

[0044] The plugging slurry B4 prepared in this comparative example, and the performance test results of its gel formation at a reaction temperature of 90 °C are shown in Table 1.

[0045] Comparative Example 5 A rheological response crosslinked resin plugging slurry is basically the same as Example 1, except that: The crosslinking agent used is 4 parts.

[0046] The plugging slurry B5 prepared in this comparative example, and the performance test results of its gel formation at a reaction temperature of 90 °C are shown in Table 1.

[0047] Comparative Example 6 A rheological response crosslinked resin plugging slurry is basically the same as Example 1, except that: The dosage of the retarder is 0.2 parts.

[0048] The plugging slurry B6 prepared in this comparative example, and the performance test results of its gel formation at a reaction temperature of 70 °C are shown in Table 1.

[0049] Comparative Example 7 Experiments were carried out using polyacrylamide and basic chromium acetate, and its preparation method includes: By volume, 0.5 parts of polyacrylamide are added to 100 parts of water. After stirring evenly, 0.2 parts of basic chromium acetate are added to make the plugging slurry B7. The performance test results of its gel formation at a reaction temperature of 60 °C are shown in Table 1.

[0050] Comparative Example 8 Experiments were carried out using polyacrylamide and basic chromium acetate, and its preparation method includes: By volume, 0.5 parts of polyacrylamide were added to 100 parts of the base liquid. After stirring evenly, 0.2 parts of basic chromium acetate were added to prepare the plugging slurry B8. The performance test results of its gelation at a reaction temperature of 60 °C are shown in Table 1.

[0051] Experimental Example Performance Test 1. Viscosity Measurement According to GB / T 15357-2014, a viscometer was used for viscosity testing. The liquid sample to be tested (i.e., the plugging slurry prepared in the examples and comparative examples) was poured into the test tank of the viscometer to ensure that the rotor was completely immersed in the liquid. The instrument was started and the viscosity reading was recorded. The test steps were repeated until stable measurement results were obtained.

[0052] 2. Judgment of Pumpable Time The gelation state was evaluated by visual inspection. The plugging slurries prepared in the above examples and comparative examples were poured into glass bottles, the bottle caps were tightened, and they were placed in a water bath at the corresponding gelation reaction temperature. They were taken out every 10 minutes, the glass bottles were rotated, and the gelation situation was observed. The time when it could not flow was used as the pumpable time and recorded.

[0053] 3. Evaluation of Pressure-bearing Capacity after Complete Gelation The plugging material experimental device QD-81 was used to carry out the pressure-bearing capacity evaluation experiment under the condition of a ball bed. The QD-81 cylinder was filled with marbles of Φ14.3 mm, and the plugging slurry was filled in the pores of the marbles. The cylinder was sealed and left standing for 7 days at a given temperature. After the plugging slurry was completely gelled, the cylinder was taken out, installed at the bottom inside of the QD-81 outer cylinder, and then 200 mL of clear water was added to the outer cylinder. The connecting bolt was removed, and the No. 6 plate (full-diameter ring) was installed and tightened. The ball valve was opened, a collection cylinder was placed at the outlet, the air source was connected, the air release valve rod of the three-way was closed, and the valve rod was opened. The outer cylinder cover of the plugging instrument was tightened, and the valve rod was screwed into the outer cylinder cover in turn to fix the three-way with a fixing pin. The timer was started, and the pipe manifold pressure regulating handle was rotated to pressurize at a speed of 2 psi per second until the plugging was damaged and the clear water in the instrument container flowed out. The maximum pressure reached was recorded.

[0054] 4. Test Results The test results are shown in Table 2.

[0055] Table 2 Experimental Results As can be seen from the data in Table 2 above, the plugging slurries of Examples 1 to 3 and Comparative Examples 1 to 7 can all form effective plugging layers and have good plugging effects. In Comparative Example 1, a high-solid-content polyacrylate was used to replace the aqueous polyurethane resin emulsion, and the viscosity of the prepared slurry decreased, and the pressure-bearing strength after gelation decreased, indicating that the acrylate resin used in this system has a lower consistency than polyurethane and is more conducive to pumping, but the mechanical strength decreases. In Comparative Examples 2 to 3, the addition amount of the aqueous emulsion was reduced, resulting in an increase in the gelation time and a significant decrease in the pressure-bearing capacity. In Comparative Example 4, the addition amount of the demulsifier was increased, the demulsification rate was accelerated, and the mechanical properties were improved, but the safe pumping time was significantly shortened, less than 3 hours, which is not conducive to on-site construction. Therefore, the addition amount of the demulsifier should not be too high. In Comparative Example 5, the addition amount of the cross-linking agent was increased, and the mechanical properties increased, indicating that a small increase in the cross-linking agent is beneficial to the gelation performance. From the performance of Example 1 after gelation at different reaction temperatures, when the gelation temperature was reduced, the pumpable time of the system increased, and the strength after complete gelation remained basically unchanged. In Comparative Example 6, the gelation temperature was reduced and the addition amount of the retarder was reduced, and the gelation time was similar to that of Example 1, indicating that this system can meet the requirement of controllable gelation time under different temperature gradients. In Comparative Example 7, the traditional chemical plugging method was used, that is, an aqueous solution of polyacrylamide was reacted with organic chromium to prepare a hydrogel plugging material. From the results, it can be seen that the initial consistency of this material is higher and the gelation strength is on the low side. In actual applications, nano-silica, calcium carbonate, mica flakes, etc. are often added for reinforcement. In Comparative Example 8, a polyacrylamide aqueous solution was prepared using a polymer drilling fluid, and this plugging slurry could not gel, indicating that the anti-drilling fluid contamination of polyacrylamide is insufficient.

[0056] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A rheological response cross-linked resin plugging slurry, characterized in that, The plugging slurry comprises the following components in parts by volume: 20 - 75 parts of base fluid, 25 - 80 parts of aqueous emulsion, 0.2 - 1 part of demulsifier, 0 - 5 parts of retarder, 0.5 - 2 parts of rheology modifier, 0 - 50 parts of weighting material, and 0.5 - 4 parts of crosslinking agent; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; Wherein, the aqueous emulsion is any one of anionic aqueous polyurethane resin and anionic aqueous acrylate resin, or a combination thereof; The crosslinking agent is used to react with the active groups in the aqueous emulsion during use for chemical crosslinking; The rheology modifier is an organic weak acid sodium salt; The demulsifier is an organic weak acid; The retarder is used to reduce the reaction rate between the aqueous emulsion and the crosslinking agent; The base fluid is a water-based drilling fluid.

2. The rheological response cross-linked resin plugging slurry according to claim 1, wherein The plugging slurry comprises the following components in parts by volume: 25 - 75 parts of base fluid, 25 - 75 parts of aqueous emulsion, 0.8 - 1 part of demulsifier, 0.2 - 1 part of retarder, 0.5 - 1 part of rheology modifier, 5 - 40 parts of weighting material, and 1 - 4 parts of crosslinking agent are added to 25 - 75 parts of base fluid; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts.

3. The rheological response cross-linked resin plugging slurry according to claim 1, wherein The aqueous polyurethane emulsion is selected from anionic high-solid-content aqueous polyurethane; Or / and, the aqueous acrylate emulsion is selected from anionic high-solid-content acrylate resin.

4. The rheological response cross-linked resin plugging slurry according to claim 1, wherein The retarder is selected from any one or more than two of sodium chloride, fatty alcohol polyoxyethylene ether carboxylate, and fatty alcohol polyoxyethylene ether; Or / and, the crosslinking agent is selected from any one or more than two of aziridine, polyethyleneimine, carbodiimide, hexamethylene diisocyanate, phenolic crosslinking agent, chromium acetate, polyetheramine, and aqueous epoxy resin crosslinking agent; Or / and, the demulsifier is selected from any one or more than two of n-octanoic acid, lauric acid, dodecanedioic acid, hexanoic acid, stearic acid, and acetic acid; Or / and, the rheology modifier is selected from any one or more than two of sodium lactate, sodium acetate, sodium citrate, and sodium ascorbate; Or / and, the weighting material is selected from any one or more than two of calcium carbonate, barite, ultrafine iron powder, bluestone powder, and ilmenite.

5. The rheological response crosslinked resin plugging slurry according to claim 1, wherein, The plugging slurry comprises the following components in parts by volume: 25 - 75 parts of base fluid, 25 - 75 parts of aqueous emulsion, 1 part of demulsifier, 0.2 - 0.5 part of retarder, 1 part of rheology modifier, 10 parts of weighting material, and 2 - 4 parts of crosslinking agent; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; Wherein, the base fluid is a polymer drilling fluid, the aqueous emulsion is anionic high-solid-content aqueous polyurethane or anionic high-solid-content acrylate resin, the demulsifier is lauric acid, the retarder is fatty alcohol polyoxyethylene ether carboxylate, the rheology modifier is sodium acetate, the weighting material is barite, and the crosslinking agent is an aqueous epoxy resin crosslinking agent.

6. The rheological response cross-linked resin plugging slurry according to claim 1, wherein The plugging slurry comprises the following components in parts by volume: 50 parts of base fluid, 50 parts of aqueous emulsion, 1 part of demulsifier, 1 part of retarder, 1 part of rheology modifier, 40 parts of weighting material, and 1 part of crosslinking agent; and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts; Among them, the base fluid is a polymer drilling fluid, the aqueous emulsion is an anionic high-solid-content acrylate resin, the demulsifier is lauric acid, the retarder is sodium chloride, the crosslinking agent is polyethyleneimine, the rheology regulator is sodium ascorbate, and the weighting material is barite.

7. The rheologically responsive cross-linked resin plugging slurry according to claim 1, characterized in that: The plugging slurry contains the following components in volume parts: 75 parts of base fluid, 25 parts of aqueous emulsion, 0.8 part of demulsifier, 0.5 part of retarder, 0.5 part of rheology regulator, 5 parts of weighting material, and 2 parts of crosslinking agent; Among them, the base fluid is a polymer drilling fluid, the aqueous emulsion is an anionic high-solid-content acrylate resin, the demulsifier is dodecanedioic acid, the retarder is sodium alcohol polyoxyethylene ether carboxylate, the crosslinking agent is aziridine crosslinking agent, the rheology regulator is sodium lactate, and the weighting material is ultrafine calcium carbonate.

8. The rheological response cross-linked resin plugging slurry according to any one of claims 1 to 7, characterized in that, The polymer drilling fluid contains: water, 4% bentonite, 0.6% potassium polyacrylate, 0.15% hydrolyzed acrylonitrile, 5% sulfonated asphalt, and 2% ultrafine calcium carbonate.

9. The preparation method of the rheological response crosslinked resin plugging slurry according to any one of claims 1 to 8, characterized in that, The preparation method includes: By volume, 25 - 80 parts of aqueous emulsion, 0.2 - 1 part of demulsifier, 0 - 5 parts of retarder, 0.5 - 2 parts of rheology regulator are added to 20 - 75 parts of base fluid, and after stirring evenly, 0 - 50 parts of weighting material and 0.5 - 3.5 parts of crosslinking agent are added, and the total volume fraction of the base fluid and the aqueous emulsion is 100 parts to obtain the plugging slurry.

10. Application of the rheology-responsive crosslinked resin plugging slurry according to any one of claims 1 - 8 in drilling plugging.

Images