Pred fluid for resin extrusion sealing fluid and preparation method of prepad fluid

Abstract

The invention belongs to the technical field of oil field development well cementation operation, and particularly relates to prepad fluid for resin extrusion sealing fluid and a preparation method of the prepad fluid. The prepad fluid comprises the following components in parts by weight: 77-89 parts of water, 5-10 parts of an interface reinforcing agent, 5-10 parts of an interface cleaning agent and 1-3 parts of a suspending agent. The cement particles on the microcrack interface of the cement sheath are removed through the macromolecule dragging effect of the suspension stabilizer, and the situation that the loose cement particles affect cementation of the resin extrusion sealing liquid and the microcrack interface is avoided; compared with crude oil molecules, the interface cleaning fluid has higher interface competitive adsorption capacity, so that the crude oil molecules are replaced to be anchored to a hydrophilic surface, and the interface crude oil removal effect is improved. Meanwhile, hydrophobic groups in molecules can participate in a resin curing reaction, so that the interface bonding strength of the resin extrusion liquid is improved. The interface reinforcing agent has a molecular bridge effect, can form firm combination between cement sheath microcracks (a silicate inorganic interface) and the resin extrusion sealing liquid (thermosetting resin), and improves the long-acting sealing performance of the extrusion sealing liquid.

Description

Technical Field

[0001] This invention belongs to the field of oilfield cementing operation technology, specifically relating to a pre-fill fluid for resin extrusion sealing fluid and its preparation method. Background Technology

[0002] In recent years, with the increasing demand for natural gas and the continuous deepening of exploration and development, downhole geological conditions and wellbore structures have become increasingly complex. Post-cementing annular pressure or wellhead gas leakage problems have become increasingly prominent. Treatment methods mostly involve regular monitoring, periodic pressure release, well workover, and the application of cement or resin materials. Resin materials are increasingly favored due to their high compressive strength, good flexibility, and good injection properties in micro-fractures without solid phase. However, micro-fractures and annular interfaces in cement sheaths often have oil and formation water adhering to them, resulting in a poor cementing environment. This severely affects the bonding between the resin sealing fluid and the micro-fracture interface, making it difficult to guarantee the long-term effectiveness of the sealing measures and failing to meet the needs of long-term development of wells with annular pressure.

[0003] To address the aforementioned problems, current solutions primarily focus on optimizing the performance of the sealing fluid. CN113930200A discloses a sealant for treating annular pressure, its preparation method, and its application. This sealant comprises a composite resin, a curing agent, a toughening agent, and a viscosity reducer. By injecting this sealant from the surface annulus into the oil and gas well annulus and curing it to seal micro-cracks in the cement sheath, effective sealing of the oil and gas well annulus can be achieved to solve the casing annulus pressure problem. This method improves the micro-crack sealing effect by optimizing the resin sealant viscosity and the mechanical properties of the cured body. However, it does not consider the influence of the cementing environment at the micro-crack interface under downhole conditions on the sealing effect. Summary of the Invention

[0004] The purpose of this invention is to provide a pre-filler for resin extrusion liquid, which solves the problem of poor sealing performance caused by poor interfacial bonding of resin extrusion liquid during annular pressurized plugging.

[0005] Another object of the present invention is to provide a method for preparing a pre-solvent for resin extrusion liquid.

[0006] Therefore, the technical solution provided by the present invention is as follows: A pre-treatment solution for resin extrusion liquid comprises the following components in parts by weight: 77-89 parts water, 5-10 parts interface enhancer, 5-10 parts interface cleaner, and 1-3 parts suspending agent. The interface enhancer is one or more of mercaptosilane coupling agents, aminosilane coupling agents, or titanate coupling agents.

[0007] The interface cleaning agent is one or both of sophorolipids and rhamnolipin.

[0008] The suspending agent is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and anionic polyacrylamide.

[0009] The mercaptosilane coupling agent is one or more of 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, or 3-mercaptopropyltrimethoxysilane.

[0010] The aminosilane coupling agent is one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and N-2-aminoethyl-3-aminopropylmethyldiethoxysilane.

[0011] The titanate coupling agent is one or more of isopropyltris(dioctyl pyrophosphate) titanate, isopropyloxydioleoyloxy(dioctyl phosphate) titanate, and isopropyloxytrioleoyloxy titanate.

[0012] The carboxymethyl cellulose has a molecular weight of 30,000-70,000, the hydroxyethyl cellulose has a molecular weight of 40,000-80,000, and the anionic polyacrylamide has a molecular weight of 4 million-7 million.

[0013] A method for preparing a pre-treatment solution for resin extrusion liquid includes the following steps: Step 1) While stirring, add the prescribed amount of suspension to the prescribed amount of water, and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a suspension aqueous solution; Step 2) Add the formulated amount of interface cleaning agent to the suspension aqueous solution, stir at 300-400 r / min for 30-60 min, then add the formulated amount of interface reinforcing agent, stir for 30-60 min, and the product is obtained.

[0014] The beneficial effects of this invention are: The pre-treatment fluid for resin sealing liquid provided by this invention removes cement particles from the interface of microcracks in the cement ring through the polymer dragging effect of the suspending stabilizer, preventing loose cement particles from affecting the bonding between the resin sealing liquid and the microcrack interface. Compared with crude oil molecules, the interface cleaning fluid has a stronger interfacial competitive adsorption capacity, thereby replacing crude oil molecules and anchoring them to the hydrophilic surface, improving the crude oil removal effect at the interface. At the same time, the hydrophobic groups in the molecules can participate in the resin curing reaction, thereby improving the interfacial bonding strength of the resin sealing liquid. The interface reinforcing agent has a molecular bridging effect, which can form a strong bond between the cement ring microcracks (silicate inorganic interface) and the resin-based sealing liquid (thermosetting resin), improving the long-term sealing performance of the sealing liquid.

[0015] This invention can effectively remove oil stains at the interface of micro-fractures and improve the cementation environment at the interface of the sealing fluid. It features good rheological properties at room temperature, low viscosity, and good squeezing performance in micro-fractures with annular pressure. The method of this invention is simple, technically reliable, and cost-controllable, and can meet the requirements of on-site construction processes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the extrusion sealing evaluation device in the embodiment.

[0017] In the diagram: 1. Sleeve; 2. Filter screen; 3. Rubber sleeve; 4. End cap; 5. Shaft core; 6. Pressing joint; 7. PTFE clamp; 8. Support cylinder liner; 9. Heating sleeve; 10. Confining pressure injection port; 11. Steel wire; 12. Thermocouple; 13. Sealing liquid layer; 14. Cement layer; 15. Sand layer; 16. Pressurization channel. 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 will now be described with reference to the accompanying drawings. 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 illustrated in the drawings 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 The present invention provides a pre-treatment liquid for resin extrusion liquid, comprising the following components in parts by weight: 77-89 parts water, 5-10 parts interface enhancer, 5-10 parts interface cleaner, and 1-3 parts suspending agent. The interface enhancer is one or more of mercaptosilane coupling agents, aminosilane coupling agents, or titanate coupling agents.

[0022] The interface cleaning agent is one or both of sophorolipids and rhamnolipin.

[0023] The suspending agent is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and anionic polyacrylamide.

[0024] The mercaptosilane coupling agent is one or more of 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, or 3-mercaptopropyltrimethoxysilane.

[0025] The aminosilane coupling agent is one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and N-2-aminoethyl-3-aminopropylmethyldiethoxysilane.

[0026] The titanate coupling agent is one or more of isopropyltris(dioctyl pyrophosphate) titanate, isopropyloxydioleoyloxy(dioctyl phosphate) titanate, and isopropyloxytrioleoyloxy titanate.

[0027] The carboxymethyl cellulose has a molecular weight of 30,000-70,000, the hydroxyethyl cellulose has a molecular weight of 40,000-80,000, and the anionic polyacrylamide has a molecular weight of 4 million-7 million.

[0028] Principle of this invention: The polymer drag effect of the suspension stabilizer removes cement particles from the interface of microcracks in the cement ring, preventing loose cement particles from affecting the bonding between the resin sealing fluid and the microcrack interface. The interface cleaning fluid, with its stronger interfacial competitive adsorption capacity compared to crude oil molecules, replaces crude oil molecules and anchors them to hydrophilic surfaces, improving the crude oil removal effect. The interface enhancer acts as a molecular bridge, forming a strong bond between the cement ring microcracks (silicate inorganic interface) and the resin sealing fluid (thermosetting resin), improving the long-term sealing performance of the sealing fluid. Simultaneously, the hydrophobic groups in the molecules can participate in the resin curing reaction, thereby increasing the interfacial bonding strength of the resin sealing fluid.

[0029] Example 2 Based on Example 1, this example provides a pre-solvent for resin extrusion liquid, comprising the following components in parts by weight: 80 parts water, 10 parts interface enhancer, 10 parts interface cleaner, and 1 part suspending agent. In this embodiment, the suspending agent is xanthan gum; the interface enhancer consists of 5 parts of 3-mercaptopropylmethyldiethoxysilane and 5 parts of 3-mercaptopropylmethyldimethoxysilane; and the interface cleaning agent consists of 5 parts of rhamnolipin and 5 parts of sophorolipid.

[0030] The preparation process is as follows: (1) Weigh 1 part xanthan gum and 80 parts water, slowly add the suspending agent to the water stirred at 500 r / min, stir at 300-400 r / min for 60-180 min to fully hydrate it, and obtain a viscous suspending agent solution. (2) Weigh out 5 parts of 3-mercaptopropylmethyldiethoxysilane and 5 parts of 3-mercaptopropylmethyldimethoxysilane; weigh out 5 parts of rhamnolipin and 5 parts of sophorolipid; (3) Add the interface cleaning agent to the suspending aqueous solution and stir at 300-400 r / min for 30 min. Then add the interface reinforcing agent and stir at 300-400 r / min for 60-90 min to obtain the pre-solvent for resin extrusion liquid.

[0031] Example 3 Based on Example 1, this example provides a pre-solvent for resin extrusion liquid, comprising the following components in parts by weight: 82 parts water, 8 parts interface enhancer, 8 parts interface cleaner, and 2 parts suspending agent.

[0032] In this embodiment, the suspending agent is hydroxyethyl cellulose; the interface enhancer consists of 5 parts of 3-mercaptopropyltrimethoxysilane and 3 parts of isopropyltris(dioctylpyrophosphate)titanate; and the interface cleaning agent consists of 5 parts of rhamnolipid and 3 parts of sophorolipid.

[0033] The preparation process is as follows: (1) Weigh 2 parts of hydroxyethyl cellulose suspending agent and 82 parts of water. Slowly add the suspending agent to the water stirred at 500 r / min and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a viscous suspending agent solution. (2) Weigh out 8 parts of interface enhancer, namely 5 parts of 3-mercaptopropyltrimethoxysilane and 3 parts of isopropyltris(dioctylpyrophosphoryloxy)titanate; weigh out 8 parts of interface cleaner, namely 5 parts of rhamnolipin and 3 parts of sophorolipid.

[0034] (3) Add the weighed interface cleaning agent to the suspending agent aqueous solution and stir at 300-400 r / min for 30 min. Then add the weighed interface reinforcing agent and stir at 300-400 r / min for 60-90 min to obtain the pre-solvent for resin extrusion liquid.

[0035] Example 4 Based on Example 1, this example provides a pre-solvent for resin extrusion liquid, comprising the following components in parts by weight: 88 parts water, 6 parts interface enhancer, 5 parts interface cleaner, and 2 parts suspending agent.

[0036] In this embodiment, the suspending agent is carboxymethyl cellulose; the interface enhancer consists of 3 parts of 3-aminopropylmethyldimethoxysilane and 3 parts of 3-mercaptopropylmethyldiethoxysilane; and the interface cleaning agent consists of 5 parts of rhamnolipin and 2 parts of sophorolipid.

[0037] The preparation process is as follows: (1) Weigh 2 parts of carboxymethyl cellulose suspending agent and 88 parts of water. Slowly add the suspending agent to the water stirred at 500 r / min and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a viscous suspending agent solution. (2) Weigh out 6 parts of interface enhancer, namely 3 parts of 3-aminopropylmethyldimethoxysilane and 3 parts of 3-mercaptopropylmethyldiethoxysilane; weigh out 5 parts of interface cleaner, namely 3 parts of rhamnolipid and 2 parts of sophorolipid fatty alcohol.

[0038] (3) Add the interface cleaning agent to the suspending aqueous solution and stir at 300-400 r / min for 30 min. Then add the weighed interface reinforcing agent and stir at 300-400 r / min for 60-90 min to obtain the pre-solvent for resin extrusion liquid.

[0039] Example 5 Based on Example 1, this example provides a pre-solvent for resin extrusion liquid, comprising the following components in parts by weight: 80 parts water, 10 parts interface enhancer, 8 parts interface cleaner, and 2 parts suspending agent.

[0040] In this embodiment, the suspending agent is anionic polyacrylamide; the interface enhancer consists of 5 parts isopropyl tris(dioctyl pyrophosphate) titanate and 5 parts isopropyl tris(dioctyl pyrophosphate) titanate; and the interface cleaning agent is rhamnolipid.

[0041] The preparation process is as follows: (1) Weigh 2 parts of anionic polyacrylamide suspending agent and 80 parts of water. Slowly add the suspending agent to the water stirred at 500 r / min and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a viscous suspending agent solution. (2) Weigh 10 parts of interface enhancer, namely 5 parts of isopropyl tris(dioctyl pyrophosphoryloxy) titanate and 5 parts of isopropyl tris(dioctyl pyrophosphoryloxy) titanate; weigh 8 parts of interface cleaner and 8 parts of rhamnolipid.

[0042] (3) Add the interface cleaning agent to the suspending aqueous solution and stir at 300-400 r / min for 30 min. Then add the weighed interface reinforcing agent and stir at 300-400 r / min for 60-90 min to obtain the pre-solvent for resin extrusion liquid.

[0043] To further illustrate the effects of this invention, sealing performance evaluation tests were conducted on the pre-treatment solutions for the resin sealing solutions prepared in Examples 2-5, and on Comparative Examples 1 and 2. The performance of the pre-treatment solution was evaluated using a self-made cement ring seal failure evaluation device, as shown in the example below. Figure 1As shown. The evaluation device includes a sleeve 1 and a filter screen 2. The inner wall of the sleeve 1 is provided with a rubber sleeve 3 and a filter screen 2. From top to bottom, the sleeve is provided with a shaft core 5 and a supporting cylinder sleeve 8. A confining pressure injection port 10 is opened on the sleeve 1. A heating sleeve 9 is provided outside the sleeve 1, which is heated by a thermocouple 12. An end cap 4 is provided between the shaft core 5 and the top of the sleeve 1. A clamping joint 6 is provided in the middle of the shaft core 5. A 1-5mm steel wire 11 is inserted into the clamping joint 6. A PTFE clamp 7 is provided at the bottom of the clamping joint 6. A pressure channel 16 is provided at the upper end of the clamping joint 6.

[0044] The preparation process of Comparative Example 1 is as follows: (1) Weigh 1 part of the suspending agent xanthan gum and 89 parts of water. Slowly add the suspending agent to the water stirred at 500 r / min and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a viscous suspending solution. (2) Weigh 10 parts of the interface enhancer, namely 5 parts of 3-mercaptopropylmethyldiethoxysilane and 5 parts of 3-mercaptopropylmethyldimethoxysilane; (3) Add the weighed interface enhancer to the suspending aqueous solution of step (1) and stir at 300-400 r / min for 60-90 min to obtain the pretreatment solution of Comparative Example 1.

[0045] Comparative Example 2 (1) Weigh 1 part of the suspending agent xanthan gum and 89 parts of water. Slowly add the suspending agent to the water stirred at 500 r / min and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a viscous suspending solution. (2) Weigh out 10 parts of the interface cleaning agent, which are 5 parts of rhamnolipin and 5 parts of sophorolipin; (3) Add the weighed interface cleaning agent to the suspending aqueous solution of step (1) and stir at 300-400 r / min for 60-90 min to obtain the pretreatment solution of Comparative Example 2.

[0046] Experimental procedure: 1. Construct a φ2mm channel to seal with cement stone to simulate downhole microfractures; fill the evaluation device vessel with 20mm high 80-mesh quartz sand ( Figure 1 Medium sand layer 15), after inserting φ2mm steel wire 11 in the middle, inject cement grout to a height of 100mm. Figure 1 (14) After the cement slurry has initially set, pull out the steel wire 11 and wait for it to set for 48 hours.

[0047] 2. Add a mixture of crude oil and water into the cavity of the vessel, pressurize it to squeeze the mixture into the simulated fracture, fill the fracture with the mixture, and let it stand for more than 4 hours to simulate the micro-fracture sealing environment in the well.

[0048] 3. Continuously pump resin sealing liquid pre-filler into the cavity of the vessel body to fill the microcracks with the pre-filler and ensure that the contact time between the pre-filler and the microcracks is greater than 7 minutes.

[0049] 4. Inject the resin extrusion liquid into the cavity of the vessel body, and apply pressure to force the resin extrusion liquid into the simulated microcracks, so that the simulated cracks are filled with resin extrusion liquid. Figure 1 The resin sealing liquid layer was heated to 60℃ and allowed to solidify for 24 hours until the resin sealing liquid was completely cured. Nitrogen gas was then introduced to measure the pressure at which gas channeling occurred, which is the sealing pressure of the resin sealing liquid for microcracks. The experimental results are shown in Table 1.

[0050] Table 1. Test data of examples and comparative samples under conditions of 160℃.

[0051] As shown in Table 1, the viscosities of Examples 2, 3, 4, and 5 were all below 50 mPa·s at 60°C, indicating good flow properties. After flushing with the pre-fluid, the pressure resistance of the microcrack sealing was approximately 7 MPa. Compared with Comparative Examples 1 and 2, the pressure resistance was significantly improved, demonstrating that the pre-fluid can effectively enhance the bonding strength of the microcrack interface in the resin-based sealing liquid system.

[0052] 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 pre-treatment solution for resin extrusion liquid, characterized in that: It includes the following components in parts by weight: 77-89 parts water, 5-10 parts interface enhancer, 5-10 parts interface cleaner, and 1-3 parts suspending agent.

2. The pre-treatment solution for resin extrusion liquid according to claim 1, characterized in that: The interface enhancer is one or more of mercaptosilane coupling agents, aminosilane coupling agents, or titanate coupling agents.

3. The pre-treatment solution for resin extrusion liquid according to claim 1, characterized in that: The interface cleaning agent is one or both of sophorolipids and rhamnolipin.

4. The pre-treatment solution for resin extrusion liquid according to claim 1, characterized in that: The suspending agent is one or more of xanthan gum, carboxymethyl cellulose, hydroxyethyl cellulose, and anionic polyacrylamide.

5. The pre-treatment solution for resin extrusion liquid according to claim 2, characterized in that: The mercaptosilane coupling agent is one or more of 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, or 3-mercaptopropyltrimethoxysilane.

6. The pre-treatment liquid for resin extrusion liquid according to claim 2, characterized in that: The aminosilane coupling agent is one or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and N-2-aminoethyl-3-aminopropylmethyldiethoxysilane.

7. The pre-treatment solution for resin extrusion liquid according to claim 2, characterized in that: The titanate coupling agent is one or more of isopropyltris(dioctyl pyrophosphate) titanate, isopropyloxydioleoyloxy(dioctyl phosphate) titanate, and isopropyloxytrioleoyloxy titanate.

8. The pre-treatment solution for resin extrusion liquid according to claim 4, characterized in that: The carboxymethyl cellulose has a molecular weight of 30,000-70,000, the hydroxyethyl cellulose has a molecular weight of 40,000-80,000, and the anionic polyacrylamide has a molecular weight of 4 million-7 million.

9. The method for preparing a pre-treatment solution for resin extrusion liquid according to claim 1, characterized in that: Includes the following steps: Step 1) While stirring, add the prescribed amount of suspension to the prescribed amount of water, and stir at 300-400 r / min for 60-180 min to fully hydrate it and obtain a suspension aqueous solution; Step 2) Add the formulated amount of interface cleaning agent to the suspension aqueous solution, stir at 300-400 r / min for 30-60 min, then add the formulated amount of interface reinforcing agent, stir for 30-60 min, and the product is obtained.

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