Epoxy resin plugging agent for chemical water plugging of horizontal well and preparation method of epoxy resin plugging agent

Abstract

The invention discloses an epoxy resin plugging agent for chemical water plugging of a horizontal well, which is composed of the following components in percentage by mass: 15-25% of E44 epoxy resin, 15-25% of n-butyl glycidyl ether, 25-35% of curing agent, 5-8% of coupling agent and 5-8% of flexibilizer, the mass of the n-butyl glycidyl ether is 15-25% of the mass of the E44 epoxy resin, the mass of the coupling agent is 25-35% of the mass of the E44 epoxy resin, and the mass of the flexibilizer is 10-30% of the mass of the E44 epoxy resin. The invention further discloses a preparation method of the epoxy resin plugging agent for chemical water plugging of the horizontal well. The epoxy resin plugging agent prepared by the preparation method disclosed by the invention is good in flexibility, high in compression strength, high in temperature resistance and high in shear resistance, and effectively solves the technical problems that in the prior art, the bearing pressure is relatively low after plugging, and an original leakage point is easy to leak again in a fracturing process; and compared with the existing epoxy resin plugging agent, the plugging agent has the advantage of long curing time, and has strong applicability in chemical water plugging of the horizontal well.

Description

Technical Field

[0001] The invention belongs to the technical field of resin plugging agents for oil fields, and in particular relates to an epoxy resin plugging agent for chemical water plugging of horizontal wells. The invention also relates to a preparation method of the resin plugging agent. Background Art

[0002] In recent years, with the continuous advancement of horizontal well development and fracturing technology, horizontal well oil production has become an important way to efficiently develop oil fields. At present, the treatment of horizontal wells mainly adopts cement plugging system for plugging. In recent years, similar chemical plugging methods such as gel and chemical cement have also appeared. However, most of them still have low pressure resistance after plugging, or the original leak point leaks again during the fracturing process, and the success rate of high pressure resistance after plugging is very low. Therefore, a resin plugging agent is proposed, which has the characteristics of strong flow ability, good plugging effect, high adhesion strength, high compressive strength, strong temperature resistance, etc., so as to provide new ideas for the preparation of plugging materials for chemical water plugging of horizontal wells in low permeability oil fields and the application of resin plugging agents.

[0003] In this regard, a Chinese invention patent with a publication date of August 6, 2014 and publication number of CN103965846A discloses a two-component epoxy resin water plugging agent and a method of using the same. The product prepared by the two-component epoxy resin water plugging agent will not produce gel during the water plugging process, has less damage to the oil flow channel, and the product degradation rate after the epoxy resin curing reaction is slow, so the water plugging effect lasts for a long time. The inorganic core material in the present invention can provide a carrier for the main reactant. At a higher formation temperature, the epoxy resin and the polyamine enter a molten state. After the curing reaction occurs, they are integrated into one and can fill the gap space, reducing the amount of epoxy resin used, thereby significantly reducing the cost of the water plugging material.

[0004] However, although the above patents propose a method for preparing plugging agents using epoxy resin as raw materials, they still have the defect of short initial setting time and are not very suitable for chemical water plugging in horizontal wells. Therefore, it is urgent to develop a new epoxy resin plugging agent for chemical water plugging in horizontal wells to solve the technical problem that the original leak point is prone to leakage again during the existing fracturing process. Summary of the invention

[0005] The purpose of the present invention is to provide an epoxy resin plugging agent for chemical water plugging of horizontal wells, which solves the technical problems of low pressure bearing after plugging in the prior art and easy re-leakage of the original leakage point during the fracturing process.

[0006] Another object of the present invention is to provide a method for preparing the epoxy resin plugging agent.

[0007] The technical solution adopted by the present invention is that the epoxy resin plugging agent for chemical water plugging of horizontal wells is composed of the following components: E44 epoxy resin, n-butyl glycidyl ether, a curing agent, a coupling agent, and a toughening agent. Calculated by mass percentage, taking the mass of the E44 epoxy resin as the basic part, the n-butyl glycidyl ether is 15% to 25% of the mass of the E44 epoxy resin, the curing agent is 25% to 35% of the mass of the E44 epoxy resin, the coupling agent is 5% to 8% of the mass of the E44 epoxy resin, and the toughening agent is 6% to 8% of the mass of the E44 epoxy resin.

[0008] The present invention is also characterized in that:

[0009] The epoxy equivalent of E44 epoxy resin is 200-250 g / eq, and the density of E44 epoxy resin is 1.1 g / cm 3 ~1.3g / cm 3 .

[0010] The curing agent is one of ethylenediamine or diethylenetriamine.

[0011] The coupling agent is one or more of aminopropyltriethoxysilane, aminopropyltrimethoxysilane or higher fatty acid imidazoline mixed in any proportion.

[0012] The toughening agent is any one of acetone, neopentyl glycol diglycidyl ether, propylene oxide butyl ether, benzyl glycidyl ether or dioctyl phthalate.

[0013] Another technical solution adopted by the present invention is a method for preparing an epoxy resin plugging agent for chemical water plugging in horizontal wells, comprising the following steps:

[0014] S1: Weigh E44 epoxy resin, n-butyl glycidyl ether, curing agent, coupling agent, and toughening agent respectively;

[0015] S2: weighing E44 epoxy resin and n-butyl glycidyl ether, mixing and stirring at room temperature to obtain an initial mixture, adding weighing toughening agent to the initial mixture, stirring evenly, and then adding weighing curing agent and coupling agent, stirring evenly, to obtain a glue plugging agent;

[0016] S3: The glue plugging agent is placed in an oven at 50±0.5°C and dried for three days to obtain the epoxy resin plugging agent for chemical water plugging of horizontal wells.

[0017] The present invention is also characterized in that:

[0018] The n-butyl glycidyl ether is 15% to 25% of the mass of the E44 epoxy resin, the curing agent is 25% to 35% of the mass of the E44 epoxy resin, the coupling agent is 5% to 8% of the mass of the E44 epoxy resin, and the toughening agent is 6% to 8% of the mass of the E44 epoxy resin.

[0019] The beneficial effects of the present invention are as follows: the epoxy resin plugging agent obtained by the preparation method of the present invention has good flexibility, high compression strength, strong temperature resistance and strong shear resistance, which effectively solves the technical problems of low pressure bearing after plugging in the prior art and easy leakage at the original leakage point during the fracturing process, and is of great significance for improving the recovery rate and development effect of the oil reservoir. Compared with the existing epoxy resin plugging agent, it has the advantage of long curing time and strong applicability in chemical water plugging of horizontal wells. DETAILED DESCRIPTION

[0020] The present invention is described in detail below in conjunction with specific implementation modes.

[0021] The invention provides an epoxy resin plugging agent for chemical water plugging of horizontal wells. The epoxy resin plugging agent is composed of the following components: E44 epoxy resin, n-butyl glycidyl ether, a curing agent, a coupling agent and a toughening agent. By mass percentage, the n-butyl glycidyl ether accounts for 15% to 25% of the mass of the E44 epoxy resin, the curing agent accounts for 25% to 35% of the mass of the E44 epoxy resin, the coupling agent accounts for 5% to 8% of the mass of the E44 epoxy resin, and the toughening agent accounts for 6% to 8% of the mass of the E44 epoxy resin.

[0022] The epoxy equivalent of E44 epoxy resin is 200-250 g / eq, and the density of E44 epoxy resin is 1.1 g / cm 3 ~1.3g / cm 3 ;

[0023] The curing agent is one of ethylenediamine or diethylenetriamine. The curing agent plays an important role in the plugging agent. During the reaction, it can open the epoxy groups on the epoxy resin so that they are cross-linked together to form macromolecules, which have the effect of plugging leaks after curing.

[0024] The coupling agent is one or more of aminopropyltriethoxysilane, aminopropyltrimethoxysilane or higher fatty acid imidazoline mixed in any proportion. Preferably, the coupling agent is higher fatty acid imidazoline, whose fatty acid long-chain functional group can improve flexibility and imidazoline functional group improves the bonding strength of the plugging agent.

[0025] The toughening agent is any one of acetone, neopentyl glycol diglycidyl ether, propylene oxide butyl ether, benzyl glycidyl ether and dioctyl phthalate. Preferably, the amount of acetone is 8% of the mass of E44 epoxy resin, the amount of neopentyl glycol diglycidyl ether is 6% of the mass of E44 epoxy resin, the amount of propylene oxide butyl ether is 8% of the mass of E44 epoxy resin, the amount of benzyl glycidyl ether is 7% of the mass of E44 epoxy resin, and the amount of dioctyl phthalate is 7% of the mass of E44 epoxy resin. The addition of the toughening agent can not only reduce the decrease in resin viscosity, but also improve the flexibility of the plugging agent. Preferably, the toughening agent is neopentyl glycol diglycidyl ether.

[0026] In the present invention, n-butyl glycidyl ether is used as a diluent. The diluent contains epoxy groups in the middle, which can participate in the curing reaction and form a three-dimensional cross-linked structure, which has a toughening effect on the plugging agent. The compressive strength, tensile strength and shear strength of the plugging agent system are improved, but the initial setting time is reduced. The proportion can be adjusted according to needs during use.

[0027] The preparation method of the above-mentioned plugging agent comprises the following steps:

[0028] S1: Weigh E44 epoxy resin, n-butyl glycidyl ether, curing agent, coupling agent, and toughening agent respectively, wherein n-butyl glycidyl ether accounts for 15% to 25% of the mass of E44 epoxy resin, the curing agent accounts for 25% to 35% of the mass of E44 epoxy resin, the coupling agent accounts for 5% to 8% of the mass of E44 epoxy resin, and the toughening agent accounts for 6% to 8% of the mass of E44 epoxy resin;

[0029] S2: weighing E44 epoxy resin and n-butyl glycidyl ether, mixing and stirring at room temperature to obtain an initial mixture, adding weighing toughening agent to the initial mixture, stirring evenly, and then adding weighing curing agent and coupling agent, stirring evenly, to obtain a glue plugging agent;

[0030] S3: The glue plugging agent is placed in an oven at 50±0.5° C. and dried for three days to obtain a flexible high-strength epoxy resin plugging agent for chemical water plugging of horizontal wells.

[0031] Example 1

[0032] Add 100g of epoxy resin E44 and 20g of n-butyl glycidyl ether into a container and stir evenly. The epoxy equivalent of the epoxy resin is 200g / eq and the density of the E44 epoxy resin is 1.1g / cm 3 , make it fully blended, add 6g of neopentyl glycol diglycidyl ether, mix evenly, then add 6g of higher fatty acid imidazoline and 30g of diethylenetriamine, stir evenly, put the obtained partial glue liquid in a container, seal it, place it in an oven at 50℃, and dry it for three days to obtain epoxy resin glue liquid A.

[0033] Example 2

[0034] Add 100g epoxy resin E44 and 15g n-butyl glycidyl ether into a beaker and stir evenly. The epoxy equivalent of the epoxy resin is 220g / eq and the density of the E44 epoxy resin is 1.2g / cm 3 , make it fully blended, add 8g acetone, mix evenly, then add 5g aminopropyltriethoxysilane and 25g ethylenediamine, stir evenly, put the obtained partial glue liquid in a container, seal it, place it in an oven at 50.5℃, and dry it for three days to obtain epoxy resin glue liquid B.

[0035] Example 3

[0036] Add 100g epoxy resin E44 and 25g n-butyl glycidyl ether into a beaker and stir evenly. The epoxy equivalent of the epoxy resin is 250g / eq and the density of the E44 epoxy resin is 1.3g / cm 3 , make it fully blended, add 8g of propylene oxide butyl ether, mix evenly, then add 8g of aminopropyltrimethoxysilane and 35g of diethylenetriamine, stir evenly, put the obtained partial glue liquid in a container, seal it, place it in an oven at 50°C, and dry it for three days to obtain epoxy resin glue liquid C.

[0037] Example 4

[0038] Add 100g epoxy resin E44 and 23g n-butyl glycidyl ether into a beaker and stir evenly. The epoxy equivalent of the epoxy resin is 230g / eq and the density of the E44 epoxy resin is 1.3g / cm 3 , make it fully blended, add 7g of benzyl glycidyl ether, mix evenly, then add 4g of aminopropyl trimethoxy silane, g of higher fatty acid imidazoline and 33g of diethylenetriamine, stir evenly, put the obtained partial glue liquid in a container, seal it, place it in an oven at 50°C, and dry it for three days to obtain epoxy resin glue liquid D.

[0039] Comparative Example

[0040] Add 100g of epoxy resin E44 and 20g of n-butyl glycidyl ether into a container and stir evenly. The epoxy equivalent of the epoxy resin is 200g / eq and the density of the E44 epoxy resin is 1.1g / cm 3 , make it fully blended, then add 6g of higher fatty acid imidazoline and 30g of diethylenetriamine, stir evenly, put the obtained partial glue liquid in a container, seal it, place it in an oven at 50℃, and dry it for three days to obtain epoxy resin glue liquid E.

[0041] The performance of the epoxy resin gelling solutions prepared in Examples 1 to 4 and the comparative example was tested. The results are shown in Table 1. The testing method is as follows:

[0042] (1) When placed in an oven for drying, use a rotational viscometer to measure the change in viscosity of the system over time, and the time when the viscosity is greater than 10000 mPa·s is recorded as the initial setting time;

[0043] (2) The obtained partial gel solution is subjected to mold casting, vacuum degassing and heating curing (50° C.), and its mechanical properties are measured using a universal tensile testing machine.

[0044] Table 1 Performance test results of samples obtained from Examples 1 to 4 and Comparative Examples

[0045] Test items Example 1 Example 2 Example 3 Example 4 Comparative Example Compression strength, MPa 101.2 111.2 96.8 100.7 42.7 Shear strength, MPa 17.6 19.1 19.5 19.3 17.9 Initial setting time (60℃), h 4.5 4 4.25 4.25 3.75 Tensile strength, MPa 52.8 54.7 35.2 51.6 16.2 Temperature resistance, ℃ ＞300 ＞300 ＞300 ＞300 ＞300

[0046] It can be seen from the test results of the comparative examples that the epoxy resin plugging agent prepared by the present invention has higher compression strength, shear strength and tensile strength than the epoxy resin plugging agent prepared by the comparative example, has higher pressure resistance, and is less likely to leak at the original leakage point during the fracturing process; and has a long initial setting time, and can be delivered to the leakage point and successfully sealed while ensuring that the epoxy resin plugging agent does not leak.

Claims

1. Epoxy resin plugging agent for chemical water plugging of horizontal wells, characterized in that: The invention is composed of the following components: E44 epoxy resin, n-butyl glycidyl ether, a curing agent, a coupling agent and a toughening agent. Calculated by mass percentage, taking the mass of the E44 epoxy resin as the basic part, the n-butyl glycidyl ether is 15% to 25% of the mass of the E44 epoxy resin, the curing agent is 25% to 35% of the mass of the E44 epoxy resin, the coupling agent is 5% to 8% of the mass of the E44 epoxy resin, and the toughening agent is 6% to 8% of the mass of the E44 epoxy resin.

2. The epoxy resin plugging agent for chemical water plugging of horizontal wells according to claim 1, characterized in that: The epoxy equivalent of the E44 epoxy resin is 200-250 g / eq, and the density of the E44 epoxy resin is 1.1 g / cm 3 ~1.3g / cm 3 .

3. The epoxy resin plugging agent for chemical water plugging of horizontal wells according to claim 1, characterized in that: The curing agent is one of ethylenediamine or diethylenetriamine.

4. The epoxy resin plugging agent for chemical water plugging of horizontal wells according to claim 1, characterized in that: The coupling agent is one or more of aminopropyltriethoxysilane, aminopropyltrimethoxysilane or higher fatty acid imidazoline mixed in any proportion.

5. The epoxy resin plugging agent for chemical water plugging of horizontal wells according to claim 1, characterized in that: The toughening agent is any one of acetone, neopentyl glycol diglycidyl ether, propylene oxide butyl ether, benzyl glycidyl ether or dioctyl phthalate.

6. The method for preparing the epoxy resin plugging agent for chemical water plugging of horizontal wells according to any one of claims 1 to 5, characterized in that: The steps include: S1: Weigh E44 epoxy resin, n-butyl glycidyl ether, curing agent, coupling agent, and toughening agent respectively; S2: weighing E44 epoxy resin and n-butyl glycidyl ether, mixing and stirring at room temperature to obtain an initial mixture, adding weighing toughening agent to the initial mixture, stirring evenly, and then adding weighing curing agent and coupling agent, stirring evenly, to obtain a glue plugging agent; S3: Put the glue plugging agent into an oven at 50±0.5° C. and dry it for three days to obtain the epoxy resin plugging agent for chemical water plugging of horizontal wells.

7. The method for preparing the epoxy resin plugging agent for chemical water plugging of horizontal wells according to claim 6, characterized in that: In the S1, the n-butyl glycidyl ether accounts for 15% to 25% of the mass of the E44 epoxy resin, the curing agent accounts for 25% to 35% of the mass of the E44 epoxy resin, the coupling agent accounts for 5% to 8% of the mass of the E44 epoxy resin, and the toughening agent accounts for 6% to 8% of the mass of the E44 epoxy resin.