High-filtration-loss expansion plugging agent for oil-based drilling fluid and preparation method thereof

Abstract

The invention relates to the technical field of petroleum drilling engineering, in particular to a high-filtration-loss expansion plugging agent for oil-based drilling fluid and a preparation method thereof.The preparation method includes the following steps that a rigid material, an expansion resin material, a mixed fiber material and a percolation material in raw materials are evenly mixed according to the required amount, and the high-filtration-loss expansion plugging agent for the oil-based drilling fluid is obtained; wherein the raw materials comprise the following components in parts by mass: 30-50 parts of a rigid material, 20-30 parts of an expanded resin material, 10-20 parts of a mixed fiber material and 10-20 parts of a percolation material. The high-filtration-loss expansion plugging agent for the oil-based drilling fluid can quickly form a plugging layer, has the characteristic of high strength, can effectively reduce the permeation effect of the drilling fluid and improve the leakage prevention and plugging effects, can be used for treating leakage and solving the leakage problems of partial leakage and multi-point well leakage, and has the characteristics of wide application range, simple plugging construction, high safety, low cost and the like. The effect taking is quick.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum drilling engineering, and is a high-filtration-loss expansion plugging agent for oil-based drilling fluid and a preparation method thereof. Background Art

[0002] Oil-based drilling fluid is a high-end working fluid in the drilling field. It has excellent performance and can prevent drilling risks. However, it is expensive because it needs to be prepared with diesel. When used in leaky formations, a large amount of drilling fluid is prone to leak into the formation, causing economic losses.

[0003] As drilling progresses to deeper layers, the demand for high-performance oil-based drilling fluids continues to increase, and the problem of oil-based drilling fluids is becoming more and more prominent. In order to reduce the amount of leakage, various plugging materials are used for application evaluation. Studies have found that commonly used plugging materials have poor plugging effects in oil-based drilling fluids. The reason is that diesel is a non-polar solution, and the interaction between it and the plugging agent is weak. After the plugging agent enters the formation, it is not easy to squeeze and compact, resulting in repeated leakage. The plugging materials and plugging technologies that match the oil-based drilling fluid are currently an urgent problem to be solved in the promotion and application of oil-based drilling fluids.

[0004] In view of the performance characteristics of oil-based drilling fluid in well leakage, effective plugging requires that the plugging slurry first quickly enters the formation to form a preliminary plugging, and then expands in the plugging layer to squeeze the plugging layer densely. To this end, it is necessary to develop a new plugging agent that meets the performance requirements.

[0005] In response to the demand for oil-based plugging materials, high filtration loss plugging agents can quickly enter the formation to form a plugging layer and have high application prospects. However, they belong to the category of water-based plugging materials and need to solve the problem of matching with oil-based drilling fluids. Therefore, the new type of oil-based drilling fluid high filtration loss expansion plugging agent is in line with the demand, has more advanced technology, and can achieve better application effects. Summary of the invention

[0006] The present invention provides a high filtration expansion plugging agent for oil-based drilling fluid, which overcomes the deficiencies of the prior art and can effectively solve the problem that the plugging agent is not easy to be squeezed and compacted after entering the formation and the plugging effect is poor.

[0007] One of the technical solutions of the present invention is achieved through the following measures: a preparation method of a high-loss swelling plugging agent for oil-based drilling fluid, comprising the following steps: uniformly mixing the rigid material, swelling resin material, mixed fiber material, and percolation material in the raw materials according to the required amounts, so as to obtain the high-loss swelling plugging agent for oil-based drilling fluid; wherein the raw materials include 30 to 50 parts of rigid material, 20 to 30 parts of swelling resin material, 10 to 20 parts of mixed fiber material, and 10 to 20 parts of percolation material in parts by mass.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The high filtration and swelling plugging agent for oil-based drilling fluid comprises, by weight, 40 parts of rigid material, 25 parts of swelling resin material, 15 parts of mixed fiber material and 20 parts of percolation material.

[0009] The high filtration and swelling plugging agent for oil-based drilling fluid comprises, by weight, 40 parts of rigid material, 30 parts of swelling resin material, 10 parts of mixed fiber material and 20 parts of percolation material.

[0010] The rigid material is a mixture of silicon carbide powder with a particle size of 150 mesh and silicon carbide powder with a particle size of 300 mesh, wherein the weight ratio of the silicon carbide powder with a particle size of 150 mesh to the silicon carbide powder with a particle size of 300 mesh is 2 to 4:4 to 5.

[0011] The above-mentioned expansion resin material is acrylic ester microporous resin particles with a particle size of 80 mesh to 150 mesh, a pore size distribution of 1.5 nanometers to 2.5 nanometers, and a microporosity of ≥50%.

[0012] The mixed fiber material is a mixture of modified plant fiber and aluminum silicate mineral fiber in a mass ratio of 1:2 to 3. The fiber aspect ratio of the mixed fiber material is 10 to 50:1, and the diameter is 10um to 20um.

[0013] The modified plant fiber is plant fiber that has been subjected to alkalization and degreasing treatment.

[0014] The above-mentioned filtration material is porous pearlite powder with a particle size of 200 meshes.

[0015] The second technical solution of the present invention is achieved through the following measures: a high fluid loss expansion plugging agent for oil-based drilling fluid is prepared by a preparation method of a high fluid loss expansion plugging agent for oil-based drilling fluid.

[0016] The high filtration expansion plugging agent for oil-based drilling fluid of the present invention can quickly form a plugging layer, has the characteristics of high strength, can effectively reduce the penetration of drilling fluid, and improve the leakage prevention and plugging effect. It can be used to control leakage, solve the leakage problems of partial leakage and multi-point well leakage, and has the characteristics of wide application range, simple plugging construction, high safety and quick effect. DETAILED DESCRIPTION

[0017] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; the normal temperature and room temperature in the present invention generally refer to the temperature of 15°C to 25°C, and are generally defined as 25°C.

[0018] The present invention will be further described below in conjunction with embodiments: Example 1: The preparation method of the high filtration swelling plugging agent for oil-based drilling fluid comprises the following steps: uniformly mixing the rigid material, swelling resin material, mixed fiber material and percolation material in the raw materials according to the required amounts to obtain the high filtration swelling plugging agent for oil-based drilling fluid, wherein the raw materials comprise, by mass, 30 to 50 parts of rigid material, 20 to 30 parts of swelling resin material, 10 to 20 parts of mixed fiber material and 10 to 20 parts of percolation material.

[0019] Example 2: As an optimization of the above example, a high filtration swelling plugging agent for oil-based drilling fluid, the raw materials by mass include 40 parts of rigid material, 25 parts of swelling resin material, 15 parts of mixed fiber material, and 20 parts of percolation material.

[0020] Example 3: As an optimization of the above example, a high filtration swelling plugging agent for oil-based drilling fluid, the raw materials by mass include 40 parts of rigid material, 30 parts of swelling resin material, 10 parts of mixed fiber material, and 20 parts of percolation material.

[0021] Embodiment 4: As an optimization of the above embodiment, the rigid material is a mixture of 150 mesh silicon carbide powder and 300 mesh silicon carbide powder, wherein the weight ratio of 150 mesh silicon carbide powder to 300 mesh silicon carbide powder is 2 to 4:4 to 5. The rigid material used in the present invention is lipophilic and can be well dispersed in the oil phase, providing a certain strength support for the plugging layer.

[0022] Embodiment 5: As an optimization of the above embodiment, the expansion resin material is acrylic microporous resin particles with a particle size of 80 to 150 meshes, a pore size distribution of 1.5 nanometers to 2.5 nanometers, and a microporosity of ≥50%. The expansion resin material selected in the present invention can absorb oil and expand in the oil-based drilling fluid to form a deformed body with a certain elasticity, which serves the purpose of squeezing and deforming the plugging layer, and serves to improve the density of the plugging and improve the pressure bearing capacity.

[0023] Embodiment 6: As an optimization of the above embodiment, the mixed fiber material is a mixture of modified plant fiber and aluminum silicate mineral fiber in a mass ratio of 1:2 to 3, and the fiber aspect ratio of the mixed fiber material is 10 to 50:1, and the diameter is 10um to 20um. The mixed fiber material plays the role of hanging and bridging, and strengthening the efficiency of the reinforcement in the process of forming the plugging layer, thereby improving the pressure bearing capacity of the plugging layer.

[0024] Example 7: As an optimization of the above Example 6, the modified plant fiber is plant fiber that has been subjected to alkalization and degreasing treatment.

[0025] Example 8: As an optimization of the above example, the filtration material is porous perlite powder with a particle size of 200 meshes. The porous perlite powder can form a loose accumulation during the filtration process, and the channels in the porous perlite powder can allow the liquid phase in the drilling fluid to quickly discharge the plugging layer, shortening the time for the plugging agent to be compacted.

[0026] The raw material particle size of the high filtration expansion plugging agent for oil-based drilling fluid of the present invention is small, and it is easy to enter the leakage channels and spaces of various sizes of openings. Under the action of pressure difference, a plugging layer can be quickly formed, and the oil-based drilling fluid can be effectively prevented from continuing to leak to the formation. The raw material contains resin elastic particles that can absorb oil and expand. The internal extrusion force is generated by the oil absorption and expansion effect in the plugging layer, which helps to improve the strength of the plugging layer, reduce the penetration of the drilling fluid, and improve the leak prevention and plugging effect. Secondly, the material of the present invention has strong lipophilicity, and can form a stable suspended dispersion state in the oil-based drilling fluid, which is suitable for pumping construction. In specific application, the high filtration expansion plugging agent for oil-based drilling fluid of the present invention can be used alone in oil-based drilling fluid, and can also be matched with bridging materials of different particle sizes. According to the size of the leakage formation channel, the bridging particles matched with it are selected to form a mixed plugging slurry with this material, which has wide practicality, and the method for preparing the plugging slurry on site is simple and easy to operate.

[0027] Example 9: The high-loss swelling plugging agent for oil-based drilling fluid includes raw materials by weight: 40g of rigid material, 25g of swelling resin material, 15g of mixed fiber material, and 20g of percolation material. Among them, the rigid material is 150-mesh silicon carbide powder and 300-mesh silicon carbide powder, and the weight ratio of 150-mesh silicon carbide powder to 300-mesh silicon carbide powder is 3:5; the swelling resin material is acrylic microporous resin particles with a particle size of 80 to 150 mesh, a pore size distribution of 1.5 nanometers to 2.5 nanometers, and a microporosity of ≥50%; the mixed fiber material is modified plant fiber and aluminum silicate mineral fiber with a weight ratio of 1:3. The components in each raw material are mixed evenly to obtain a plugging agent.

[0028] Embodiment 10: The high-loss swelling plugging agent for oil-based drilling fluid includes raw materials by weight: 35g rigid material, 30g swelling resin material, 10g mixed fiber material, and 20g percolation material. Among them, the rigid material is 150-mesh silicon carbide powder and 300-mesh silicon carbide powder, and the weight ratio of 150-mesh silicon carbide powder to 300-mesh silicon carbide powder is 3:5; the swelling resin material is acrylic microporous resin particles with a particle size of 80 to 120 meshes; the mixed fiber material is modified plant fiber and aluminum silicate mineral fiber with a weight ratio of 1:2. The components in each raw material are mixed evenly to obtain a plugging agent.

[0029] Example 11: The high-loss swelling plugging agent for oil-based drilling fluid includes raw materials by weight: 30g rigid material, 30g swelling resin material, 15g mixed fiber material, and 25g percolation material. Among them, the rigid material is 150-mesh silicon carbide powder and 300-mesh silicon carbide powder, and the weight ratio of 150-mesh silicon carbide powder to 300-mesh silicon carbide powder is 3:4; the swelling resin material is acrylic microporous resin particles with a particle size of 80 to 120 meshes; the mixed fiber material is modified plant fiber and aluminum silicate mineral fiber with a weight ratio of 1:3. The components in each raw material are mixed evenly to obtain a plugging agent.

[0030] Comparative example: Commercially available high filtration loss plugging agent Diasea L-M.

[0031] Performance Test: The high filtration swelling plugging agent for oil-based drilling fluid prepared in Examples 9 to 11 and the comparative example were selected for performance testing. The high filtration swelling plugging agent for oil-based drilling fluid prepared in Examples 8 to 10 and Diasea L-M were respectively prepared with diesel to prepare plugging slurry, and the preparation steps were as follows: Measure 5 cups of 300 mL diesel respectively and place them on a high-speed stirrer; weigh 90 g of the samples prepared in Examples 9 to 11 and the plugging agent Diasea L-M respectively and set aside. Turn on the stirrer and add the four plugging agents to the 5 cups of diesel respectively at 11000 rpm and stir for 20 minutes, during which time use a glass rod to scrape off the adherents on the cup wall.

[0032] The plugging slurry samples prepared above were subjected to the following tests: ① Rapid filtration test: Stir the four plugging slurry samples evenly and pour them into the dry and clean medium-pressure filter loss meter slurry cup to the scale line, cover the filter loss meter slurry cup cover tightly, and place a 500 mL beaker at the lower outlet of the filter loss meter to receive the filtrate. Adjust the gas source to 0.7MPa, and immediately open the air inlet valve, and start timing at the same time until gas is ejected from the discharge port, stop timing immediately, and record the filter loss time. The experimental results are shown in Table 1.

[0033] ②Needle penetration test: Place the plug formed after rapid filtration directly on the base of the cement standard consistency setting time tester, install an initial setting test needle with a diameter of 1.13mm±0.05mm and a length of 50mm±1mm, adjust the tightening screw so that the needle tip just touches the surface of the filter cake, adjust the tightening screw of the test rod so that it is just aligned with the "0" position of the scale, loosen the tightening screw, and read the scale value after the test needle is stable, which is the needle penetration. The experimental results are shown in Table 1.

[0034] It can be seen from Table 1 that Diasea L-M takes a long time to filter out at medium pressure, and the mud cake formed is soft and not dense enough. However, the samples of Examples 8 to 10 can filter out quickly at medium pressure, and the filter cake formed is dense and has a certain initial strength.

[0035] ③Oil-based drilling fluid compatibility test: Oil-based drilling fluid formula: 240mL 0# diesel + 7.2g organic soil + 6.2mL primary emulsifier (fatty acid derivative) + 4mL auxiliary emulsifier (fatty acid amide derivative) + 3.6mL wetting agent + 4g calcium oxide + 60mL 25% calcium chloride solution + barite powder (density added to 1.50g / cm 3 ).

[0036] Preparation method of oil-based drilling fluid: Measure 240mL 0# diesel and add it to the preparation container, start stirring, set the speed to 11000rpm, add 7.2g organic soil under high-speed stirring, and stir for 10min; then use a syringe to extract 6.2mL primary emulsifier, 4mL auxiliary emulsifier, 3.6mL wetting agent, and add them to the preparation container in sequence, then add 4g calcium oxide, add it under high-speed stirring, stir for 30min, then add 60mL 25% calcium chloride solution, stir for 30min under high-speed stirring, and finally slowly add barite powder until the system density is 1.50g / cm 3 , stirring for 30 minutes, the oil-based drilling fluid slurry is obtained. The required range of various performance data of oil-based drilling fluid is shown in Table 2.

[0037] 5 portions of oil-based drilling fluid prepared according to the above method were measured, 400 ml each, and the high-speed stirrer was turned on, and the speed was adjusted to 11000 rpm; 16 g of the high filtration expansion plugging agent for oil-based drilling fluid and the plugging agent Diasea L-M prepared in Examples 8 to 10 were weighed, and added to 4 portions of oil-based drilling fluid respectively under stirring, and the remaining 1 portion of oil-based drilling fluid was used as a blank sample, and stirred for 10 minutes. After stirring, the 5 samples were poured into an aging tank, put into a roller furnace, and aged at 150°C for 16 hours, and then tested for their performance. When testing the rheology, the temperature of the constant temperature heating jacket was controlled at 50°C. The test results are shown in Table 3. According to the test data in Table 3, after adding the high filtration expansion plugging agent for oil-based drilling fluid, the rheology of the entire oil-based drilling fluid was less affected; after adding Diasea L-M to the oil-based drilling fluid, the demulsification voltage was significantly reduced and the rheology increased. The high-loss swelling plugging agent for oil-based drilling fluid of the present invention has various properties significantly better than the plugging agent Diasea L-M. When the high-loss swelling plugging agent for oil-based drilling fluid of the present invention is applied to oil-based drilling fluid, after the high-loss swelling plugging agent for oil-based drilling fluid is formulated into a plugging slurry and enters the leaking formation, the plugging slurry undergoes rapid filtration loss under the pressure difference between the drilling fluid column and the formation pressure, and a plugging layer is quickly formed in the formation cracks. The swelling resin component in the plugging layer has the property of oil absorption and swelling, and absorbs oil and expands in the plugging layer to generate swelling pressure, which squeezes the micropores in the plugging layer, produces the effect of compaction and improving the plugging strength, and effectively fills the leaking channel.

[0038] In summary, the high filtration expansion plugging agent for oil-based drilling fluid of the present invention can quickly form a plugging layer, effectively preventing the oil-based drilling fluid from continuing to leak into the formation, and the plugging layer has great strength, can reduce the permeability of the drilling fluid, and improve the leak prevention and plugging effect. It can be used to control leakage, solve partial leakage and multi-point well leakage problems, and has the characteristics of wide application range, simple plugging construction, high safety and quick effect.

[0039] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for preparing a high filtration swelling plugging agent for oil-based drilling fluid, characterized in that The method comprises the following steps: uniformly mixing the rigid material, the expansion resin material, the mixed fiber material and the percolation material in the raw materials according to the required amounts, so as to obtain a high filtration-loss expansion plugging agent for oil-based drilling fluid; wherein the raw materials comprise, by weight, 30 to 50 parts of the rigid material, 20 to 30 parts of the expansion resin material, 10 to 20 parts of the mixed fiber material and 10 to 20 parts of the percolation material.

2. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to claim 1, characterized in that The high filtration expansion plugging agent for oil-based drilling fluid comprises 40 parts of rigid material, 25 parts of expansion resin material, 15 parts of mixed fiber material and 20 parts of percolation material by weight.

3. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to claim 1, characterized in that The high filtration swelling plugging agent for oil-based drilling fluid comprises 40 parts of rigid material, 30 parts of swelling resin material, 10 parts of mixed fiber material and 20 parts of percolation material by weight.

4. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to any one of claims 1 to 3, characterized in that The rigid material is a mixture of silicon carbide powder with a particle size of 150 meshes and silicon carbide powder with a particle size of 300 meshes, wherein the weight ratio of the silicon carbide powder with a particle size of 150 meshes to the silicon carbide powder with a particle size of 300 meshes is 2 to 4:4 to 5.

5. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to any one of claims 1 to 4, characterized in that The expansion resin material is acrylic microporous resin particles with a particle size of 80 meshes to 150 meshes, a pore size distribution of 1.5 nanometers to 2.5 nanometers, and a microporosity of ≥50%.

6. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to any one of claims 1 to 5, characterized in that The mixed fiber material is a mixture of modified plant fiber and aluminum silicate mineral fiber in a mass ratio of 1:2 to 3. The fiber aspect ratio of the mixed fiber material is 10 to 50:1, and the diameter is 10um to 20um.

7. The method for preparing the high fluid loss expansion plugging agent for oil-based drilling fluid according to claim 6, characterized in that The modified plant fiber is a plant fiber that has been subjected to an alkalization and degreasing treatment.

8. The method for preparing the high fluid loss swelling plugging agent for oil-based drilling fluid according to any one of claims 1 to 7, characterized in that The filtration material is porous pearlite powder with a particle size of 200 meshes.

9. A high fluid loss swelling plugging agent for oil-based drilling fluid obtained by the preparation method of the high fluid loss swelling plugging agent for oil-based drilling fluid according to claims 1 to 8.

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