One-bag type oil-based drilling fluid plugging agent and preparation method thereof

Abstract

The invention relates to the technical field of petroleum drilling engineering plugging agents, in particular to a one-bag type oil-based drilling fluid plugging agent and a preparation method thereof.The one-bag type oil-based drilling fluid plugging agent is prepared from, by weight, 20-30 parts of bridging materials, 10-15 parts of fiber materials, 15-25 parts of elastic materials and 30-40 parts of filling materials; the oil-based drilling fluid plugging agent is prepared according to the following method: uniformly mixing the required amount of bridging material, fiber material, elastic material and filling material to obtain the one-bag type oil-based drilling fluid plugging agent. The plugging agent is simple to prepare on site, can be obtained only after mixing, can be used for plugging while drilling by adjusting the composition proportion of the bridging particles, the elastic material and the flexible fibers, can enter leakage channels and spaces with various opening sizes within a certain crack size range, can be used for plugging and forming a barrier, does not need to replace a drilling tool combination, and is convenient to operate and convenient to use. And the operation period is shortened.

Description

Technical Field

[0001] This invention relates to the field of plugging agents for oil drilling engineering, specifically a "one-bag" oil-based drilling fluid plugging agent and its preparation method. Background Technology

[0002] In recent years, as oil and gas development has moved towards deeper reservoirs, new challenges have arisen, particularly the complex problem of managing lost circulation in deep formations. Compared to water-based drilling fluids, oil-based drilling fluids possess natural advantages such as superior lubricity, high-temperature stability, and shale inhibition, making them widely used in drilling operations in high-temperature, deep reservoirs. However, when encountering lost circulation formations during drilling, traditional water-based plugging materials are largely ineffective in controlling the losses. Due to the high cost of formulating oil-based drilling fluids, improper loss control inevitably delays the drilling cycle, causing significant economic losses. Therefore, developing plugging agents suitable for oil-based drilling fluids has become an urgent problem to solve. Developing highly efficient oil-based drilling fluid plugging agents can effectively solve the problem of lost circulation, shorten the drilling cycle, reduce costs, and further promote the development of deep oil and gas reservoirs. This research direction has significant application prospects and economic implications.

[0003] Currently, there are many water-based drilling fluid plugging products on the market, but relatively few plugging products specifically for oil-based drilling fluids. Existing oil-based drilling fluid plugging technologies use conventional sealing materials such as single-layer sealants, walnut shells, cottonseed hulls, and mica sheets. These products are limited in variety, have limited pressure resistance, and are prone to carbonization at high temperatures, resulting in poor plugging effectiveness.

[0004] Therefore, in view of the above situation, the development of a "one-bag" oil-based drilling fluid plugging agent will have good market prospects in the application of oil-based drilling. Summary of the Invention

[0005] This invention provides a "one-bag" oil-based drilling fluid plugging agent and its preparation method, which overcomes the shortcomings of the prior art. It can effectively solve the problems of the existing oil-based drilling fluid leakage plugging agents in the drilling process, such as the single product, limited pressure bearing capacity, easy carbonization at high temperature, and poor plugging effect.

[0006] One of the technical solutions of the present invention is achieved by the following measures: a "one-bag" oil-based drilling fluid plugging agent raw material, by weight, includes 20 to 30 parts of bridging material, 10 to 15 parts of fiber material, 15 to 25 parts of elastic material, and 30 to 40 parts of filler material, and is prepared by the following method: the required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned bridging material is a mixture of polyvinyl acetate particles with a particle size of 0.5 mm to 1 mm and manganese calcite particles with a particle size of 1 mm to 3 mm, wherein the weight ratio of polyvinyl acetate particles to manganese calcite particles in the mixture is 2 to 4: 1 to 5.

[0008] The aforementioned bridging material is a mixture of polyvinyl acetate particles with a particle size of 0.5 mm to 1 mm and manganese calcite particles with a particle size of 1 mm to 3 mm, wherein the weight ratio of polyvinyl acetate particles to manganese calcite particles in the mixture is 2 to 4: 1 to 5.

[0009] The aforementioned fiber material is a mixture of magnesia fiber and sepiolite fiber or oil-absorbing cotton fiber in a weight ratio of 1:1, and the length of the fiber material is less than 3 mm.

[0010] The aforementioned fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1.

[0011] The aforementioned elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm, wherein the weight ratio of acrylate rubber to ethylene propylene rubber in the mixture is 1:1.

[0012] The aforementioned filler material is micro-nano-sized quartz sand powder.

[0013] The aforementioned filler material is quartz sand powder with a particle size of 50nm to 5um.

[0014] The second technical solution of the present invention is achieved by the following measures: a method for preparing a "one-bag" oil-based drilling fluid plugging agent, which is carried out according to the following method: the required amount of bridging material, fiber material, elastic material and filler material are mixed evenly to obtain a "one-bag" oil-based drilling fluid plugging agent.

[0015] This invention is simple to prepare on-site, requiring only mixing to obtain the desired result. By adjusting the proportions of bridging particles, elastic materials, and flexible fibers, it can plug leaks while drilling. Within a certain range of crack size, it can enter and seal leakage channels and spaces of various opening sizes, forming a barrier. Moreover, it eliminates the need to change the drill bit assembly, saving on the operation cycle. Detailed Implementation

[0016] This invention is not limited to the following embodiments; specific implementation methods can be determined based on the technical solution of this invention and actual circumstances. Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are well-known and commonly used chemical reagents and chemical products in the prior art.

[0017] The present invention will be further described below with reference to embodiments: Example 1: The "one-bag" oil-based drilling fluid plugging agent is prepared by mixing the raw materials by weight, including 20 to 30 parts of bridging material, 10 to 15 parts of fiber material, 15 to 25 parts of elastic material, and 30 to 40 parts of filler material, according to the following method: The required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent.

[0018] Example 2: The "one-bag" oil-based drilling fluid plugging agent, by weight, comprises 20 or 30 parts of bridging material, 10 or 15 parts of fiber material, 15 or 25 parts of elastic material, and 30 or 40 parts of filler material, and is prepared by the following method: the required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent.

[0019] Example 3: As an optimization of the above example, the bridging material is a mixture of polyvinyl acetate particles with a particle size of 0.5 mm to 1 mm and manganese calcite particles with a particle size of 1 mm to 3 mm, wherein the weight ratio of polyvinyl acetate particles to manganese calcite particles in the mixture is 2 to 4: 1 to 5.

[0020] In this invention, the bridging support material serves to bridge and provide support in the gaps between strata.

[0021] Example 4: As an optimization of the above example, the fiber material is a mixture of brucite fiber and sepiolite fiber or oil-absorbing cotton fiber in a weight ratio of 1:1, and the length of the fiber material is less than 3 mm.

[0022] The fiber material in this invention has a length of less than 3mm, good toughness, and a maximum temperature resistance of 400℃. As a monomeric material, it can be effectively dispersed in oil-based materials, suspending solid particles. As a plugging material, after entering the leaking layer, due to its strong toughness and good dispersion, it can well wrap around and adhere to the bridging particles or well wall, interlacing reinforcing bars between the bridging particles to increase the plugging strength.

[0023] Example 5: As an optimization of the above example, the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1.

[0024] In this invention, a mixture of magnesia fiber and sepiolite fiber is used as the fiber material, which has good high temperature resistance, high toughness, and can be well wrapped and attached to the cross-linking particles.

[0025] Example 6: As an optimization of the above example, the elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm, wherein the weight ratio of acrylate rubber to ethylene propylene rubber in the mixture is 1:1.

[0026] In this invention, the elastic material has strong elasticity and toughness. As a plugging material, it deforms and embeds itself in the pores initially sealed by the bridging particles due to the pressure difference between the inside and outside of the well wall, making the plugging barrier more robust. At the same time, its elastic properties can effectively prevent formation backflow after depressurization.

[0027] Example 7: As an optimization of the above examples, the filling material is micro-nano-sized quartz sand powder.

[0028] In this invention, micro- and nano-sized quartz sand powder is used as a filler material. Its function is to enter the micropores of the initial blockage formed by the bridging support particles, form a tight seal, and utilize the property of micro- and nano-particles to change the wettability of the oil phase on its surface, so that the permeability of the oil phase drops sharply and the permeability of the bridge plug is reduced to an extremely low level, thereby completely sealing the leak layer.

[0029] Example 8: As an optimization of the above examples, the filling material is quartz sand powder with a particle size of 50nm to 5um.

[0030] Example 9: The preparation method of the "one-bag" oil-based drilling fluid plugging agent is as follows: the required amount of bridging material, fiber material, elastic material and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent.

[0031] The beneficial effects of this invention are as follows: In this invention, the specific ratio of bridging particles, elastic materials, and flexible fibers allows them to enter and seal leakage channels and spaces of various opening sizes within a certain crack size range, forming a barrier. The micro-nano-scale sealing material in this invention can refill the formed barrier and further seal the leakage channel; at the same time, the micro-nano-scale particles can form an oil-repellent film on the well wall, which can effectively slow down the intrusion of oil-based mud into the formation, prevent leakage and protect the stability of the well wall, and solve the problem that conventional bridging materials cannot prevent oil-based drilling fluid leakage after forming a blockage.

[0032] Example 10: This "one-bag" oil-based drilling fluid plugging agent, by weight, comprises 225g of bridging material, 112.5g of fiber material, 112.5g of elastic material, and 300g of filler material, prepared according to the following method: The required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent. The bridging material consists of polyvinyl acetate particles with a particle size of 0.5mm to 1mm and manganese oxide particles with a particle size of 1mm to 3mm. The mixture consists of calcite particles in which the weight ratio of polyvinyl acetate particles to manganese calcite particles is 4:1; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1; the elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm in a weight ratio of acrylate rubber to ethylene propylene rubber in a weight ratio of 1:1; and the filler is quartz sand powder with a particle size of 50 nm to 5 μm.

[0033] Example 11: This "one-bag" oil-based drilling fluid plugging agent, by weight, comprises 187.5g of bridging material, 112.5g of fiber material, 187.5g of elastic material, and 262.5g of filler material, prepared according to the following method: The required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent. The bridging material consists of polyvinyl acetate particles with a particle size of 0.5mm to 1mm and particles with a particle size of 1mm to 3mm. The mixture is composed of manganese calcite particles, in which the weight ratio of polyvinyl acetate particles to manganese calcite particles is 4:2; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1; the elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm, in which the weight ratio of acrylate rubber and ethylene propylene rubber is 1:1; and the filler is quartz sand powder with a particle size of 50 nm to 5 μm.

[0034] Example 12: This "one-bag" oil-based drilling fluid plugging agent, by weight, comprises 225g of bridging material, 112.5g of fiber material, 112.5g of elastic material, and 300g of filler material, prepared according to the following method: The required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent. The bridging material consists of polyvinyl acetate particles with a particle size of 0.5mm to 1mm and manganese oxide particles with a particle size of 1mm to 3mm. The mixture consists of calcite particles in which the weight ratio of polyvinyl acetate particles to manganese calcite particles is 3:5; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1; the elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm in a weight ratio of acrylate rubber to ethylene propylene rubber in a weight ratio of 1:1; and the filler is quartz sand powder with a particle size of 50 nm to 5 μm.

[0035] Example 13: This "one-bag" oil-based drilling fluid plugging agent, by weight, comprises 187.5g of bridging material, 112.5g of fiber material, 187.5g of elastic material, and 262.5g of filler material, prepared according to the following method: The required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain the "one-bag" oil-based drilling fluid plugging agent. The bridging material consists of polyvinyl acetate particles with a particle size of 0.5mm to 1mm and particles with a particle size of 1mm to 3mm. The mixture is composed of manganese calcite particles, in which the weight ratio of polyvinyl acetate particles to manganese calcite particles is 2:4; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1; the elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm, in which the weight ratio of acrylate rubber and ethylene propylene rubber is 1:1; and the filler is quartz sand powder with a particle size of 50 nm to 5 μm.

[0036] Comparative Example 1: Commonly used on-site leak sealing formula: 30g walnut shells (0.1mm to 1mm), 30g rigid material WNDK-1, 20g composite leak sealant LCM-2, and 20g drilling leak sealant JD-5. Mix the above components evenly to obtain the leak sealant.

[0037] Comparative Example 2: Commonly used on-site leak sealing formula: 10g walnut shells (1mm to 3mm), 20g walnut shells (0.1mm to 1mm), 30g rigid material WNDK-1, 20g composite leak sealant LCM-3, and 20g drilling leak sealant JD-5. Mix all the above components evenly to obtain the leak sealant.

[0038] Performance testing The "one-bag" oil-based drilling fluid leak stopper of the present invention obtained in Examples 10 to 13 was selected for performance testing, and Comparative Example 1 and Comparative Example 2 were selected as comparative samples.

[0039] This leak stopper can be formulated in various types of oil-based drilling fluids. To ensure the reliability of the test results and minimize variables, 5# white oil used for mud preparation was adopted as the base mud to formulate the leak-stopping slurry in this experiment. The leak stoppers of Examples 10 to 13 and Comparative Example 1 and Comparative Example 2 were respectively formulated with white oil into leak-stopping slurries, and the formulation steps are as follows; (1) Measure 6 cups of 3000 mL white oil respectively, place them on a D90-type mixer and stir at the maximum speed; add 150 g of organophilic clay respectively, and stir for 20 min for standby; 750 g of the prepared Example samples and Comparative Example samples were reserved for standby.

[0040] (2) Start the D90-type mixer to stir at the maximum speed, add the 6 kinds of leak stoppers into 6 cups of white oil respectively, stir for 15 min, and scrape off the adherents on the cup wall with a glass rod during this period.

[0041] The prepared leak-stopping slurry samples were subjected to a seam plate pressure-bearing capacity test: Pour the "one-bag" oil-based drilling fluid leak stopper obtained in Example 10 into a QD-2 type leak detector (seam plate 1 mm), tighten the tank lid, connect the pressurized pipeline, and let it stand for 5 min. Open the discharge port, open the gas source to pressurize, first apply a pressure of 0.7 MPa, keep the pressure stable for 10 min, then slowly pressurize to 5 MPa, keep the pressure stable for 30 min, and measure its filtration loss. If the filtration loss is less than 1000 mL, it is qualified. The "one-bag" oil-based drilling fluid leak stopper obtained in Example 11 and the leak stopper obtained in Comparative Example 1 were also tested according to the above method respectively. The experimental results are shown in Table 1.

[0042] Pour the "one-bag" oil-based drilling fluid leak stopper obtained in Example 12 into a QD-2 type leak detector (seam plate 3 mm), tighten the tank lid, connect the pressurized pipeline, and let it stand for 5 min. Open the discharge port, open the gas source to pressurize, first apply a pressure of 0.7 MPa, keep the pressure stable for 10 min, then slowly pressurize to 5 MPa, keep the pressure stable for 30 min, and measure its filtration loss. If the filtration loss is less than 1000 mL, it is qualified. The "one-bag" oil-based drilling fluid leak stopper obtained in Example 13 and the leak stopper obtained in Comparative Example 1 were also tested according to the above method respectively. The seam plate pressure-bearing capacity test results of the oil-based "one-bag" plugging agent are shown in Table 1.

[0043] As can be seen from Table 1, the filtration losses of the leak stoppers obtained in Comparative Examples 1 to 2 all exceeded 1000 mL. While the filtration losses of the "one-bag" oil-based drilling fluid leak stoppers of the present invention obtained in Examples 10 to 13 were all much less than 1000 mL, and they could effectively plug the cracks.

[0044] In summary, the present invention is simple to prepare on-site, requiring only mixing to obtain the desired result. By adjusting the proportions of bridging particles, elastic materials, and flexible fibers, it can be used for leak plugging during drilling. Within a certain range of crack size, it can enter and seal leakage channels and spaces of various opening sizes, forming a barrier. Furthermore, it eliminates the need to change the drill bit assembly, thus saving on the operation cycle.

[0045] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A "one-bag" oil-based drilling fluid plugging agent, characterized in that... The raw materials, by weight, include 20 to 30 parts of bridging material, 10 to 15 parts of fiber material, 15 to 25 parts of elastic material, and 30 to 40 parts of filler material, and are prepared according to the following method: the required amounts of bridging material, fiber material, elastic material, and filler material are mixed evenly to obtain a "one-bag" oil-based drilling fluid plugging agent.

2. The "one-bag" oil-based drilling fluid plugging agent according to claim 1, characterized in that... The bridging material is a mixture of polyvinyl acetate particles with a particle size of 0.5 mm to 1 mm and manganese calcite particles with a particle size of 1 mm to 3 mm, wherein the weight ratio of polyvinyl acetate particles to manganese calcite particles in the mixture is 2 to 4: 1 to 5.

3. The "one-bag" oil-based drilling fluid plugging agent according to claim 1 or 2, characterized in that... The fiber material is a mixture of magnesia fiber and sepiolite fiber or oil-absorbing cotton fiber in a weight ratio of 1:1, and the length of the fiber material is less than 3mm.

4. The "one-bag" oil-based drilling fluid plugging agent according to claim 3, characterized in that... The fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:

1.

5. The "one-bag" oil-based drilling fluid plugging agent according to claim 1, 2, 3, or 4, characterized in that... The elastic material is a mixture of acrylate rubber with a particle size of 0.1 mm to 0.5 mm and ethylene propylene rubber with a particle size of 0.1 mm to 0.5 mm, wherein the weight ratio of acrylate rubber to ethylene propylene rubber in the mixture is 1:

1.

6. The "one-bag" oil-based drilling fluid plugging agent according to any one of claims 1 to 5, characterized in that... The filler material is micro-nano-sized quartz sand powder.

7. The "one-bag" oil-based drilling fluid plugging agent according to claim 6, characterized in that... The filler material is quartz sand powder with a particle size of 50nm to 5um.

8. A method for preparing a "one-bag" oil-based drilling fluid plugging agent according to any one of claims 1 to 7, characterized in that... The following method is used: Mix the required amount of bridging material, fiber material, elastic material and filler material evenly to obtain a "one-bag" oil-based drilling fluid plugging agent.

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