Modified resin anti-collapse blocking agent for environment-friendly drilling fluid and preparation method of modified resin anti-collapse blocking agent

Abstract

The invention relates to the technical field of oil field drilling and production materials, and provides a modified resin anti-collapse blocking agent for environment-friendly drilling fluid and a preparation method thereof.The modified resin anti-collapse blocking agent is prepared from, by weight, 50 parts of modified resin, 5-15 parts of carboxymethyl cellulose, 10-20 parts of nano calcium carbonate, 1-5 parts of surfactant, 10-15 parts of fruit shells and 10-20 parts of water; the modified resin comprises the following raw materials: sulfonated phenolic resin and an ethylene-vinyl alcohol copolymer in a weight ratio of 49: (1-6). According to the technical scheme, the problems that an anti-collapse plugging agent in the prior art is weak in pressure bearing capacity and large in leakage amount are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield drilling materials, and in particular to a modified resin anti-collapse plugging agent for environmentally friendly drilling fluid and a preparation method thereof. Background Art

[0002] In the field of drilling engineering, lost circulation and wellbore collapse are undoubtedly extremely serious problems. With the continuous increase in drilling depth, practical engineering has placed more stringent requirements on efficient anti-collapse plugging technology. Anti-collapse plugging agents, as a commonly used plugging material, can achieve effective plugging of cracks of various sizes through adsorption, cross-linking, and filling.

[0003] However, currently available anti-collapse plugging agents generally suffer from poor pressure-bearing capacity. These agents, with weak pressure-bearing capacity, struggle to form an effective sealing layer, significantly increasing drilling fluid loss and, in turn, the risk of wellbore collapse. Therefore, developing an anti-collapse plugging agent with strong pressure-bearing capacity and minimal loss is of vital practical significance. Summary of the Invention

[0004] The present invention provides a modified resin anti-collapse plugging agent for environmentally friendly drilling fluid and a preparation method thereof, which solves the problems of weak pressure bearing capacity and large leakage of the anti-collapse plugging agent in the related art.

[0005] The technical solutions of the present invention are as follows: The present invention provides an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid, the raw materials of which include the following components in parts by weight: 50 parts of modified resin, 5-15 parts of carboxymethyl cellulose, 10-20 parts of nano-calcium carbonate, 1-5 parts of surfactant, 10-15 parts of fruit shells, and 10-20 parts of water; The raw materials of the modified resin include sulfonated phenolic resin and ethylene-vinyl alcohol copolymer in a weight ratio of 49:1-6.

[0006] As a further technical solution, the method for preparing the modified resin comprises the following steps: blending the sulfonated phenolic resin and the ethylene-vinyl alcohol copolymer, extruding, and granulating to obtain the modified resin.

[0007] As a further technical solution, the temperature during the extrusion is 200-220°C.

[0008] As a further technical solution, the particle size of the nano calcium carbonate is 50-100 nm.

[0009] As a further technical solution, the nano-calcium carbonate is modified nano-calcium carbonate, and the raw materials of the modified nano-calcium carbonate include nano-calcium carbonate and p-toluidine.

[0010] In this invention, the inventors discovered that modifying nano-calcium carbonate with p-toluidine can further enhance the pressure-bearing capacity of the modified resin anti-collapse plugging agent and further reduce leakage. It is speculated that using p-toluidine to modify the nano-calcium carbonate can form weak interactions between the aromatic rings of the nano-calcium carbonate and the modified resin, further enhancing the interaction between the inorganic rigid particles and the organic resin, thereby further enhancing the pressure-bearing capacity of the modified resin anti-collapse plugging agent and further reducing leakage.

[0011] As a further technical solution, the weight ratio of p-toluidine to nano-calcium carbonate is 5-10:100.

[0012] In the present invention, when the weight ratio of p-toluidine to nano-calcium carbonate is 5-10:100, it helps to further enhance the pressure bearing capacity of the modified resin anti-collapse plugging agent and further reduce the leakage.

[0013] As a further technical solution, the preparation method of the modified nano-calcium carbonate comprises the following steps: dispersing nano-calcium carbonate in ethanol, adding p-toluidine, mixing evenly, reacting, and drying to obtain the modified nano-calcium carbonate.

[0014] As a further technical solution, during the reaction, the temperature is 40-50° C. and the reaction time is 3-5 hours.

[0015] As a further technical solution, the surfactant includes one or more of polyoxyethylene fatty alcohol ether, sucrose fatty acid ester, and octylphenol polyoxyethylene ether, preferably polyoxyethylene fatty alcohol ether.

[0016] In the present invention, the addition of surfactant can, on the one hand, reduce interfacial tension and improve adsorption performance; on the other hand, it can enhance the thixotropic properties of the modified resin anti-collapse plugging agent, ensuring that it can be accurately filled into the position that needs to be plugged.

[0017] As a further technical solution, the fruit shell is one or more of walnut shell, peanut shell, and cottonseed shell, preferably walnut shell.

[0018] In the present invention, the addition of the fruit shell can play a role of bridging and filling, has a "throat-blocking" effect, and is beneficial to maintaining the stability of the blocking layer.

[0019] As a further technical solution, the particle size of the fruit shell is 1-3 mm.

[0020] The present invention also provides a method for preparing the modified resin anti-collapse plugging agent for environmentally friendly drilling fluid, comprising the following steps: uniformly mixing all components except water, then adding water and stirring to obtain the modified resin anti-collapse plugging agent.

[0021] As a further technical solution, during the stirring, the rotation speed is 1000-1500 r / min and the time is 30-60 min.

[0022] The working principle and beneficial effects of the present invention are: In this invention, the sulfonated phenolic resin is modified with an ethylene-vinyl alcohol copolymer, which facilitates the formation of an interpenetrating network within the resin. This not only enhances the strength of the modified resin anti-collapse plugging agent and improves its pressure-bearing capacity, but also makes the plugging layer denser, reducing fluid penetration and lowering leakage. Furthermore, the addition of inorganic rigid nano-calcium carbonate particles also enhances the pressure-bearing capacity of the modified resin anti-collapse plugging agent and reduces leakage. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, unless otherwise specified, the model of the sulfonated phenolic resin is SMP-2; the model of the carboxymethyl cellulose is CMC-HVT; the model of the ethylene-vinyl alcohol copolymer is EW-3021; the particle size of the nano-calcium carbonate is 50 nm; the model of the polyoxyethylene fatty alcohol ether is MOA-3B; and the particle size of the walnut shell is 2 mm.

[0025] Example 1 A method for preparing an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid comprises the following steps: uniformly mixing, by weight, 50 parts of modified resin, 5 parts of carboxymethyl cellulose, 10 parts of nano-calcium carbonate, 1 part of polyoxyethylene fatty alcohol ether, and 10 parts of walnut shells; adding 10 parts of water; and stirring at 1000 rpm for 60 minutes to obtain the modified resin anti-collapse plugging agent; The preparation method of the modified resin comprises the following steps: blending 49 parts of sulfonated phenolic resin and 1 part of ethylene-vinyl alcohol copolymer, extruding, and granulating to obtain the modified resin; During extrusion, the temperature of zone 1 is 200°C, the temperature of zone 2 is 220°C, and the temperature of zone 3 is 210°C.

[0026] Example 2 A method for preparing an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid comprises the following steps: uniformly mixing, by weight, 50 parts of a modified resin, 15 parts of carboxymethyl cellulose, 20 parts of nano-calcium carbonate, 5 parts of polyoxyethylene fatty alcohol ether, and 15 parts of walnut shells; adding 20 parts of water; and stirring at 1500 rpm for 30 minutes to obtain the modified resin anti-collapse plugging agent; The preparation method of the modified resin comprises the following steps: blending 49 parts of sulfonated phenolic resin and 6 parts of ethylene-vinyl alcohol copolymer, extruding, and granulating to obtain the modified resin; During extrusion, the temperature of zone 1 is 200°C, the temperature of zone 2 is 220°C, and the temperature of zone 3 is 210°C.

[0027] Example 3 The only difference between this embodiment and Example 2 is that in this embodiment, the nano-calcium carbonate is modified nano-calcium carbonate. The preparation method of the modified nano-calcium carbonate comprises the following steps: dispersing 100 parts of nano-calcium carbonate in 150 parts of ethanol, adding 1 part of p-toluidine, mixing uniformly, reacting at 40° C. for 5 hours, and drying to obtain modified nano-calcium carbonate.

[0028] Example 4 The only difference between this embodiment and embodiment 3 is that, when preparing modified nano-calcium carbonate in this embodiment, the reaction temperature is 50° C. and the reaction time is 3 h.

[0029] Example 5 The only difference between this embodiment and embodiment 4 is that, in this embodiment, when preparing modified nano-calcium carbonate, the weight portion of p-toluidine is 15 parts.

[0030] Example 6 The only difference between this embodiment and embodiment 4 is that, in this embodiment, when preparing modified nano-calcium carbonate, the weight portion of p-toluidine is 5 parts.

[0031] Example 7 The only difference between this embodiment and embodiment 4 is that, in this embodiment, when preparing modified nano-calcium carbonate, the weight portion of p-toluidine is 10 parts.

[0032] Comparative Example 1 The only difference between this comparative example and Example 1 is that in this comparative example, the modified resin is replaced by an equal amount of sulfonated phenolic resin.

[0033] Comparative Example 2 A method for preparing an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid comprises the following steps: uniformly mixing, by weight, 49 parts of sulfonated phenolic resin, 1 part of ethylene-vinyl alcohol copolymer, 15 parts of carboxymethyl cellulose, 20 parts of nano-calcium carbonate, 5 parts of polyoxyethylene fatty alcohol ether, and 15 parts of walnut shells; adding 20 parts of water; and stirring at 1500 r / min for 30 minutes to obtain the modified resin anti-collapse plugging agent.

[0034] Comparative Example 3 The only difference between this comparative example and Example 1 is that in this comparative example, no nano calcium carbonate is added.

[0035] The modified resin anti-collapse plugging agents prepared in Examples 1 to 7 and Comparative Examples 1 to 3 were tested for pressure bearing capacity and leakage under a 3 mm crack with reference to SY / T 5840-2007 "Indoor Test Methods for Bridging and Plugging Materials for Drilling Fluids". The amount of the modified resin anti-collapse plugging agent added was 4% of the weight of the test base slurry, and the test temperature was 130°C. The test results are shown in Table 1 below.

[0036] Table 1 Performance test results

[0037] Comparison of Example 1 and Comparative Examples 1 and 2 shows that modifying the sulfonated phenolic resin with ethylene-vinyl alcohol copolymer can enhance the pressure-bearing capacity of the modified resin anti-collapse plugging agent and reduce leakage. Comparison of Example 1 and Comparative Example 3 shows that the addition of nano-calcium carbonate can also enhance the pressure-bearing capacity of the modified resin anti-collapse plugging agent and reduce leakage.

[0038] Comparison of Example 2 with Examples 3-7 shows that modifying nano-calcium carbonate with p-toluidine helps further enhance the pressure-bearing capacity of the modified resin anti-collapse plugging agent and further reduces leakage. Comparison of Examples 4-5 with Examples 6-7 shows that when the weight ratio of p-toluidine to nano-calcium carbonate is 5-10:100, the pressure-bearing capacity of the modified resin anti-collapse plugging agent is further enhanced and the leakage is further reduced.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modified resin anti-collapse plugging agent for environmentally friendly drilling fluid, characterized in that: The raw materials include the following components in parts by weight: 50 parts of modified resin, 5-15 parts of carboxymethyl cellulose, 10-20 parts of nano calcium carbonate, 1-5 parts of surfactant, 10-15 parts of fruit shells, and 10-20 parts of water; The raw materials of the modified resin include sulfonated phenolic resin and ethylene-vinyl alcohol copolymer in a weight ratio of 49:1-6.

2. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 1, characterized in that: The preparation method of the modified resin comprises the following steps: blending sulfonated phenolic resin and ethylene-vinyl alcohol copolymer, extruding, and granulating to obtain the modified resin.

3. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 2, characterized in that: During the extrusion, the temperature is 200-220°C.

4. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 1, characterized in that: The nano calcium carbonate is modified nano calcium carbonate, and the raw materials of the modified nano calcium carbonate include nano calcium carbonate and p-toluidine.

5. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 4, characterized in that: The weight ratio of p-toluidine to nano-calcium carbonate is 5-10:

100.

6. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 4, characterized in that: The preparation method of the modified nano-calcium carbonate comprises the following steps: dispersing the nano-calcium carbonate in ethanol, adding p-toluidine, mixing evenly, reacting, and drying to obtain the modified nano-calcium carbonate.

7. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to claim 6, characterized in that: During the reaction, the temperature is 40-50° C. and the reaction time is 3-5 hours.

8. The modified resin anti-collapse plugging agent for environmentally friendly drilling fluid according to any one of claims 1 to 7, characterized in that: The surfactant includes one or more of polyoxyethylene fatty alcohol ether, sucrose fatty acid ester, and octylphenol polyoxyethylene ether; and / or The fruit shell is one or more of walnut shell, peanut shell and cottonseed shell.

9. The method for preparing an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: uniformly mixing all components except water, adding water, and stirring to obtain a modified resin anti-collapse plugging agent.

10. The method for preparing an environmentally friendly modified resin anti-collapse plugging agent for drilling fluid according to claim 9, characterized in that: During the stirring, the rotation speed is 1000-1500 r / min and the time is 30-60 min.

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