A resin cementing fluid and its preparation method and use method

Abstract

The application provides a plugging-preventing fluid for resin cementing fluid and a preparation method and use method thereof. The plugging-preventing fluid comprises the following components in parts by weight: water 100 parts, epoxy resin diluent 15-100 parts, emulsifier 5-15 parts, and suspension stabilizer 0-3 parts. The epoxy resin diluent has good compatibility with the epoxy resin, which can delay the curing time of the epoxy resin. The emulsifier can effectively reduce the interfacial tension of each component of the mixed system of the epoxy resin and the water phase of the plugging-preventing fluid, and form a relatively strong film on the surface of the epoxy resin droplets or a double electric layer on the surface of the epoxy resin droplets, so as to prevent the droplets from gathering with each other, and keep the uniform emulsion to prevent the epoxy resin from gathering and curing to leave a plug. The suspension stabilizer can make the plugging-preventing fluid better suspend the resin droplets, prevent the suspended resin droplets from settling and gathering, and hinder the epoxy resin from gathering and curing.

Description

Technical Field

[0001] This invention belongs to the field of oilfield cementing operation technology, specifically relating to an anti-clogging fluid for resin cementing fluid, its preparation method, and its application method. Background Technology

[0002] As exploration and development deepen, the number of wells with casing damage in various oilfields is increasing year by year. Cementing small casing wells and sidetracking old wells are the main technical means to tap the potential and increase production in old wells. Small casing cementing and sidetracking wells have narrow annular gaps and thin cement sheaths. Traditional oil well cement-based materials are brittle, easily damaged, and have micro-gaps in the annulus, leading to cement sheath sealing failure. Using resin cementing fluid can effectively reduce cementing construction pressure and improve annular sealing. However, during small-gap cementing construction, the resin cementing fluid is not completely displaced due to wear and breakage of the rubber plug, causing cementing fluid retention. After cementing, incompletely displaced cementing fluid remains in the casing, accumulating and blocking the channels, causing logging to fail to reach the bottom. This necessitates multiple runs of small drill strings for well cleaning or plugging, which is difficult for small-sized casing cementing, affecting construction efficiency.

[0003] Patent No. CN201310351101.9, entitled "Horizontal Well Cementing Anti-clogging Fluid and its Preparation Method," discloses an invention patent for a horizontal well cementing anti-clogging fluid and its preparation method. It primarily addresses the technical problem of cement slurry remaining in the casing after unilateral wear of the cement plug, causing logging to fail to reach the bottom. It is easy to prepare on-site, has good flow properties, and strong ability to suspend and disperse cement particles. It can prevent cement from clogging the casing passages due to deposition and saves on the drilling and plugging procedures using small drilling tools. However, this patented anti-clogging fluid is only effective for cement-based cementing fluids and is not suitable for use with resin-based cementing fluid systems. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-clogging fluid for resin cementing fluids, which has low viscosity, good fluidity, is easily soluble in water, and is easy to pump.

[0005] Another object of the present invention is to provide a method for preparing an anti-clogging fluid for resin cementing fluid.

[0006] Another objective of this invention is to provide a method for using anti-clogging fluid for resin cementing fluid, which effectively prevents resin droplets from accumulating and depositing, prevents resin cementing fluid from accumulating, solidifying, and causing blockages, ensures the passage within the casing, and solves the difficult problem of handling.

[0007] Therefore, the technical solution provided by the present invention is as follows: A resin cementing fluid anti-clogging fluid comprises the following components in parts by weight: 100 parts water; 15-100 parts of epoxy resin diluent; 5-15 parts emulsifier; 0-3 parts of suspension stabilizer.

[0008] The epoxy resin diluent is one or more of polyols, N,N-dimethylformamide, and acetone.

[0009] The emulsifier is one or more of Tween 60, emulsifier SR-10, and secondary alcohol AEO-9.

[0010] The suspension stabilizer is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and anionic polyacrylamide.

[0011] The polyol is ethylene glycol or butanediol.

[0012] The relative molecular weight of the carboxymethyl cellulose is 20,000-80,000, the relative molecular weight of the hydroxyethyl cellulose is 30,000-100,000, and the relative molecular weight of the anionic polyacrylamide is 3 million-6 million.

[0013] A method for preparing an anti-clogging fluid for resin cementing fluid includes the following steps: Step 1) Add the prescribed amount of suspension stabilizer to the prescribed amount of water while stirring, stir until it is evenly dissolved, and let it stand for 60-120 minutes to allow it to fully hydrate, thus obtaining an aqueous solution of suspension stabilizer; Step 2) Add the epoxy resin diluent and emulsifier in the prescribed amounts to the aqueous solution of the suspension stabilizer, and stir for 30-60 minutes to obtain the final product.

[0014] A method for using anti-clogging fluid for resin cementing fluid: After the resin cementing fluid is pumped out, during the displacement process, anti-clogging fluid is injected into the casing after the rubber plug. During the displacement flow, the anti-clogging fluid mixes with the resin cementing fluid to form a suspension, preventing resin droplets from agglomerating and depositing, preventing the resin cementing fluid from agglomerating, solidifying, and causing blockage, and ensuring the passage within the casing.

[0015] The amount of anti-clogging fluid used is 100-300m of the casing volume.

[0016] The beneficial effects of this invention are: The anti-clogging fluid for resin cementing provided by this invention utilizes an epoxy resin diluent characterized by low viscosity, good fluidity, and easy water solubility. This diluent reduces the viscosity of the epoxy resin, allowing it to easily form a suspension with the anti-clogging fluid during displacement flow. Simultaneously, the diluent and epoxy resin exhibit excellent compatibility, delaying the curing time of the epoxy resin. The emulsifier effectively reduces the interfacial tension of the components in the aqueous mixture of epoxy resin and anti-clogging fluid, forming a robust film or an electric double layer on the surface of epoxy resin droplets, preventing droplets from agglomerating and maintaining a uniform emulsion to prevent epoxy resin from accumulating, curing, and causing blockage. The suspension stabilizer increases shear force, allowing the anti-clogging fluid to better suspend resin droplets, preventing the sedimentation and aggregation of trapped resin droplets, and hindering epoxy resin aggregation and curing. Epoxy resin diluents can significantly reduce the viscosity of oily epoxy resins, improve the rheological properties of epoxy resin-based cementing fluids, facilitate the mixing and pumping of cementing fluid systems, and enable the cementing fluid to meet the performance requirements of cementing fluids in oil and gas well cementing.

[0017] The anti-clogging fluid of this invention has good flow properties and a density range of 1.0-1.20 g / cm³. 3 After the resin cementing fluid injection is completed, during the displacement process, 100-300m of anti-clogging fluid is injected into the casing after the rubber plug. When the rubber plug wears or is subjected to uneven stress, resin cementing fluid may flow into the casing. During the displacement flow, the anti-clogging fluid system mixes with the resin cementing fluid to form a suspension, which effectively prevents the resin droplets from accumulating and depositing, and prevents the resin cementing fluid from accumulating, solidifying, and leaving a blockage. This ensures the passage within the casing and solves the difficult problem of dealing with blockages. Detailed Implementation

[0018] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0019] Exemplary embodiments of the present invention are now described; however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments is not intended to limit the invention.

[0020] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0021] Example 1 This embodiment provides an anti-clogging fluid for resin cementing fluids, comprising the following components in parts by weight: 100 parts water; 15-100 parts of epoxy resin diluent; 5-15 parts emulsifier; 0-3 parts of suspension stabilizer.

[0022] The epoxy resin diluent is one or more of polyols, N,N-dimethylformamide, and acetone.

[0023] The emulsifier is one or more of Tween 60, emulsifier SR-10, and secondary alcohol AEO-9.

[0024] The suspension stabilizer is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and polyacrylamide.

[0025] The polyol is ethylene glycol or butanediol.

[0026] Principle of this invention: Epoxy resin diluents and epoxy resins have good compatibility, which can delay the curing time of epoxy resins. Emulsifiers can effectively reduce the interfacial tension of each component in the aqueous mixture of epoxy resin and anti-clogging liquid, and form a relatively strong film or an electric double layer on the surface of epoxy resin droplets, preventing droplets from agglomerating and maintaining a uniform emulsion to prevent epoxy resin from agglomerating and curing, thus preventing clogging. Suspension stabilizers enable the anti-clogging liquid to better suspend resin droplets, preventing the sedimentation and aggregation of stagnant resin droplets, and hindering epoxy resin aggregation and curing.

[0027] This anti-clogging fluid has good flow properties. When the rubber plug wears or is subjected to uneven force, causing resin cementing fluid to flow into the casing, the anti-clogging fluid system mixes with the resin cementing fluid during the displacement flow process to form a suspension, which effectively prevents resin droplets from accumulating and depositing, and prevents the resin cementing fluid from accumulating, solidifying, and leaving plugs. It can ensure the passage in the casing and solve the difficult problem of plug treatment.

[0028] Example 2 Based on Example 1, this example provides an anti-clogging fluid for resin cementing fluid, comprising the following components in parts by weight: 100 parts water; 20 parts epoxy resin diluent; 10 parts emulsifier; 1.5 parts of suspension stabilizer.

[0029] Preparation process: Step 1) Add the prescribed amount of suspension stabilizer to the prescribed amount of water while stirring, stir until it is evenly dissolved, and let it stand for 80 minutes to allow it to fully hydrate, thus obtaining an aqueous solution of suspension stabilizer. Step 2) Add the epoxy resin diluent and emulsifier in the prescribed amounts to the suspension stabilizer aqueous solution in sequence, and stir for 30 minutes to obtain the final product.

[0030] In this embodiment, the suspension stabilizer is carboxymethyl cellulose; the emulsifier is Tween 60; and the epoxy resin diluent is N,N-dimethylformamide.

[0031] Example 3 Based on Example 1, this example provides an anti-clogging fluid for resin cementing fluid, comprising the following components in parts by weight: 100 parts water; 30 parts epoxy resin diluent; 15 parts emulsifier; 0.5 parts of suspension stabilizer.

[0032] Preparation process: Step 1) Add the prescribed amount of suspension stabilizer to the prescribed amount of water while stirring, stir until it is evenly dissolved, let stand for 120 minutes to allow it to fully hydrate, and obtain an aqueous solution of suspension stabilizer. Step 2) Add the epoxy resin diluent and emulsifier in the prescribed amounts to the suspension stabilizer aqueous solution in sequence, and stir for 50 minutes to obtain the final product.

[0033] In this embodiment, the suspension stabilizer is anionic polyacrylamide; the emulsifier is emulsifier SR-10; and the epoxy resin diluent is a mixture of acetone and ethylene glycol in a mass ratio of 2:1.

[0034] Example 4 Based on Example 1, this example provides an anti-clogging fluid for resin cementing fluid, comprising the following components in parts by weight: 100 parts water; 50 parts epoxy resin diluent; 8 parts emulsifier; 0.5 parts of suspension stabilizer.

[0035] Preparation process: Step 1) Add the prescribed amount of suspension stabilizer to the prescribed amount of water while stirring, stir until it is evenly dissolved, and let it stand for 90 minutes to allow it to fully hydrate, thus obtaining an aqueous solution of suspension stabilizer. Step 2) Add the epoxy resin diluent and emulsifier in the prescribed amounts to the aqueous solution of the suspension stabilizer, and stir for 70 minutes to obtain the final product.

[0036] In this embodiment, the suspension stabilizer is a mixture of xanthan gum and hydroxyethyl cellulose in a mass ratio of 3:2; the emulsifier is a mixture of Tween 60 and secondary alcohol AEO-9 in a mass ratio of 1:1; and the epoxy resin diluent is a mixture of acetone and ethylene glycol in a mass ratio of 2:1.

[0037] To further illustrate the effects of the present invention, the anti-clogging fluids prepared in Examples 2-4 were subjected to the following performance tests.

[0038] 1) Thickening test A thickening experiment was conducted at 50℃ and 25MPa according to the method in GB / T19139-2012 Oil Well Cement Test Method, and the initial consistency and consistency after 48 hours of testing of the anti-blocking fluid were measured. The test results are shown in Table 1.

[0039] The anti-clogging liquid prepared in Example 2 was mixed with epoxy resin E44 at a mass ratio of 50 / 50, and a thickening test was conducted to obtain the initial consistency. The mixture was stirred at 50°C for 30 minutes, then the slurry cup was removed, the thickening oil on top of the mixture was removed, and the mixture was poured into a beaker and placed in a 50°C water bath for 48 hours. After standing, the mixture was poured into an atmospheric pressure thickener and stirred to obtain the consistency after 48 hours.

[0040] The anti-clogging liquid prepared in Example 3 was mixed with epoxy resin E44 at a mass ratio of 60 / 40, and a thickening test was performed. The consistency test after 48 hours was the same as above.

[0041] The anti-clogging liquid prepared in Example 4 was mixed with epoxy resin E51 at a mass ratio of 70 / 30, and a thickening test was performed. The consistency test after 48 hours was the same as above.

[0042] 2) Viscosity test Viscosity was tested using a rotational viscometer. The results are shown in Table 1.

[0043] 3) Density test The liquid density was measured using a digital display liquid density meter. The results are shown in Table 1.

[0044] Table 1 Performance Test Results The test results show that after the anti-clogging liquid of the present invention is left to stand, the mixture is poured into an atmospheric pressure thickener and stirred. The consistency of the mixture is 20-22 Bc, which has good fluidity, indicating that the anti-clogging liquid is pumpable.

[0045] 4) Comparative Example The horizontal well anti-clogging fluid is a cement slurry anti-clogging fluid with good performance. The horizontal well anti-clogging fluid is used as a comparison.

[0046] (1) First, prepare an aqueous solution of carboxymethyl cellulose. Weigh 5g of carboxymethyl cellulose according to the weight percentage and dissolve it in 85g of water. Stir thoroughly to ensure complete and uniform dissolution. Let it stand for 30 minutes to fully hydrate. Then, weigh 3g of filtration loss reducer, 5g of slow-release agent EDTA, and 1g of particulate dispersant in sequence and pour them into the prepared aqueous solution. Continue stirring for 20 minutes. The resulting liquid mixture is the horizontal well cementing and anti-clogging fluid. The density of the obtained horizontal well cementing and anti-clogging fluid is 1.09g / cm3, and the plastic viscosity is 32 mPa·s.

[0047] (2) After mixing the anti-clogging fluid and epoxy resin E44 in a 50 / 50 ratio, a thickening test was conducted at 50℃ and 25MPa according to the method in GB / T19139-2012 Oil Well Cement Test Method. The initial consistency of the mixture was 14Bc. After stirring for 30 minutes at 50℃, the slurry cup was removed, the thickened oil on top of the mixture was removed, and the mixture was poured into a beaker and placed in a 50℃ water bath for 48 hours. The epoxy resin settled and stratified and was prone to curing, indicating that the anti-clogging fluid for horizontal wells could not meet the anti-clogging requirements of resin cementing fluid.

[0048] Example 5 This embodiment provides a method for using anti-clogging fluid for resin cementing fluid. After the resin cementing fluid is pumped out, during the replacement process, anti-clogging fluid is injected into the casing after the rubber plug. During the replacement flow, the anti-clogging fluid mixes with the resin cementing fluid to form a suspension, preventing resin droplets from accumulating and depositing, preventing the resin cementing fluid from accumulating, solidifying, and causing blockage, and ensuring the passage within the casing.

[0049] The amount of anti-clogging fluid used is 100-300m of the casing volume.

[0050] The anti-clogging fluid of this invention has good flow properties and a density range of 1.0-1.20 g / cm3. After the resin cementing fluid is pumped in, during the replacement process, 100-300 m of anti-clogging fluid is injected into the casing after the rubber plug. When the rubber plug wears or is subjected to uneven stress, resin cementing fluid may flow into the casing. During the replacement flow, the anti-clogging fluid system mixes with the resin cementing fluid to form a suspension, which effectively prevents the resin droplets from agglomerating and depositing, and prevents the resin cementing fluid from agglomerating, solidifying, and leaving a blockage. This ensures the passage within the casing and solves the difficult problem of dealing with blockages.

[0051] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A resin cementing anti-clogging fluid, characterized in that, The components include the following parts by weight: 100 parts water; 15-100 parts of epoxy resin diluent; 5-15 parts emulsifier; 0-3 parts of suspension stabilizer; The epoxy resin diluent is one or more of polyols, N,N-dimethylformamide, and acetone; the emulsifier is one or more of Tween 60, emulsifier SR-10, and secondary alcohol AEO-9. Emulsifiers can effectively reduce the interfacial tension of each component in the aqueous mixture of epoxy resin and anti-clogging liquid, and form a relatively strong film or an electric double layer on the surface of epoxy resin microdroplets. After pumping the resin cementing fluid, the above anti-plugging fluid is injected into the casing after the rubber plug to replace the plug. The density of the anti-plugging fluid is 1.0-1.20 g / cm 3 .

2. The anti-clogging fluid for resin cementing fluid according to claim 1, characterized in that: The suspension stabilizer is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and anionic polyacrylamide.

3. The anti-clogging fluid for resin cementing fluid according to claim 1, characterized in that: The polyol is ethylene glycol or butanediol.

4. The anti-clogging fluid for resin cementing fluid according to claim 2, characterized in that: The relative molecular weight of the carboxymethyl cellulose is 20,000-80,000, the relative molecular weight of the hydroxyethyl cellulose is 30,000-100,000, and the relative molecular weight of the anionic polyacrylamide is 3 million-6 million.

5. A method for preparing an anti-clogging fluid for resin cementing fluid according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1) Add the prescribed amount of suspension stabilizer to the prescribed amount of water while stirring, stir until it is evenly dissolved, and let it stand for 60-120 minutes to allow it to fully hydrate, thus obtaining an aqueous solution of suspension stabilizer; Step 2) Add the epoxy resin diluent and emulsifier in the prescribed amounts to the aqueous solution of the suspension stabilizer, and stir for 30-60 minutes to obtain the final product.

6. The method of using an anti-clogging fluid for resin cementing fluid according to any one of claims 1-4, characterized in that: After the resin cementing fluid injection is completed, during the displacement process, an anti-blocking fluid is injected into the casing after the rubber plug. The anti-blocking fluid mixes with the resin cementing fluid during the displacement flow to form a suspension, which prevents resin droplets from accumulating and depositing, prevents the resin cementing fluid from accumulating, solidifying, and becoming a plug, and ensures the passage within the casing.

7. The method of using the anti-clogging fluid for resin cementing fluid according to claim 6, characterized in that: The amount of anti-clogging fluid used is 100-300m of the casing volume.

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