High-temperature-resistant plugging agent as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-resistant plugging agent as well as a preparation method and application thereof. The plugging agent is prepared from the following components in percentage by weight: 40-50% of high-temperature-resistant rigid particles, 30-40% of high-temperature-resistant elastic particles, 20-30% of a high-temperature-resistant flaky material and 1-10% of a high-temperature-resistant fiber material. The high-temperature-resistant elastic particles have good temperature-resistant pressure-bearing performance, the high-temperature-resistant flaky materials and the high-temperature-resistant fiber materials are high in strength, sealing can be formed on the bridge plug, gaps in the high-temperature-resistant rigid particles are plugged, meanwhile, due to the elasticity and plasticity, the effective flowing area of most gaps can be plugged through deformation, and plugging is achieved. According to indoor tests, it is found that an embodiment of 1 mm indoor plugging treats small on-site leakage (the leakage speed is smaller than or equal to 10 m < 3 > / h), an embodiment of 2-3 mm indoor plugging treats medium on-site leakage (the leakage speed is 10-30 m < 3 > / h), an embodiment of 4-5 mm indoor plugging treats large on-site leakage (the leakage speed is larger than or equal to 30 m < 3 > / h), the temperature resistance reaches 180 DEG C, the pressure bearing capacity of a crack plugging experiment reaches 20 MPa, and the technical problem of deep high-temperature drilling fluid leakage can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling plugging, and in particular relates to a high temperature resistant plugging agent and a preparation method and application thereof. Background Art

[0002] Drilling fluid leakage refers to the phenomenon that drilling fluid leaks into the formation under the action of pressure difference during the drilling process. With the improvement of the degree of oil and gas resource drilling, it has gradually moved towards complex formations such as deep and ultra-deep formations. The technical difficulty faced is plugging the leakage of drilling fluid in high-temperature formations.

[0003] At present, the plugging materials commonly used in plugging construction are usually bridging plugging materials and chemical gel plugging materials. Chemical plugging mainly plays a plugging role through the chemical reaction of polymers, including cross-linking reaction, curing reaction and other methods. Chemical plugging has a good plugging effect on malignant leakage, but the chemical plugging reaction is more intense, the construction is complex and the risk is higher. The construction process of bridging plugging materials is simple and the cost is low. It is the most commonly used on site. Traditional bridging plugging agents such as shells, walnut shells, cottonseed shells, rubber, polypropylene fibers, and single seals will fail due to carbonization under high temperature conditions.

[0004] On January 15, 2021, a rapid filtration and high temperature resistant plugging agent and preparation method were disclosed. The plugging agent includes mesh sponge, ultra-short fibers, bridging adsorbents, ultrafine calcium carbonate, elastic graphite and water. The plugging agent undergoes rapid filtration loss at the leaking layer, thereby forming a plugging layer, which can effectively improve the plugging success rate and avoid repeated leakage. However, it is not suitable for plugging operations in high-temperature formations above 150°C. Therefore, it is urgent to develop a high-temperature resistant plugging formula in the hope of meeting the plugging needs of high-temperature formations. Summary of the invention

[0005] The object of the present invention is to provide a high temperature resistant plugging agent which can resist high temperature aging at 180°C without any change in physical and chemical properties.

[0006] The purpose of the present invention is to provide a method for preparing a high temperature resistant plugging agent.

[0007] The purpose of the present invention is to provide an application of a high temperature resistant plugging agent in plugging operations during drilling, and the pressure bearing capacity of 1-5 mm cracks reaches 20 MPa.

[0008] To this end, the technical solution provided by the present invention is as follows: A high temperature resistant plugging agent is composed of the following components in percentage by weight: 40-50% of high temperature resistant rigid particles, 30-40% of high temperature resistant elastic particles, 20-30% of high temperature resistant sheet materials, and 1-10% of high temperature resistant fiber materials. The high temperature resistant rigid particles are thermosetting epoxy resin particles.

[0009] The high temperature resistant elastic particles are one or both of elastic graphite particles and expanded graphite particles.

[0010] The high temperature resistant sheet material is one or both of mica flakes and vermiculite.

[0011] The high-resistance fiber material is one or two of basalt fiber, sepiolite fiber and calcium carbonate whisker.

[0012] The high temperature resistant rigid particles, high temperature resistant elastic particles and high temperature resistant sheet materials are all mixtures of two or more different particle sizes of 4-8 mesh, 8-10 mesh, 10-40 mesh and 40-160 mesh.

[0013] The anti-high fiber material has a diameter of 20-100 μm and a length of 3-12 mm.

[0014] A method for preparing a high-temperature resistant plugging agent comprises the following steps: uniformly mixing a prescribed amount of high-temperature resistant rigid particles, high-temperature resistant elastic particles, high-temperature resistant sheet materials and high-temperature resistant fiber materials.

[0015] The invention discloses an application of a high temperature resistant plugging agent in plugging operations during drilling.

[0016] The dosage of high temperature resistant plugging agent is 10-20% of the drilling fluid mass.

[0017] The beneficial effects of the present invention are: The high temperature plugging agent provided by the present invention has high temperature rigid particles which are thermosetting epoxy resin particles and are screened into different particle sizes such as 4-8 mesh, 8-10 mesh, 10-40 mesh, and 40-160 mesh. The thermosetting epoxy resin particles are cross-linked by epoxy resin E51 and metaphenylenediamine. Due to the chemical activity of the epoxy group, it can be opened by a variety of compounds containing active hydrogen, cured and cross-linked to form a network structure; since the metaphenylenediamine curing agent is polymerized by a variety of compounds, the secondary curing of the product can be achieved. Due to the presence of a variety of high temperature resistant active groups such as phenyl, the epoxy resin cured product has high temperature resistance and can work at a temperature of 200°C for a long time. The high temperature elastic particles have good heat and pressure resistance, and the high temperature resistant sheet materials and high temperature resistant fiber materials have high strength, can form a seal on the bridge plug, bridge and fill the gap in the high temperature rigid particles, and at the same time, due to the elasticity and plasticity, the effective flow area of ​​most of the gaps can be blocked by deformation to achieve plugging.

[0018] The present invention can meet the needs of treating small, medium and large leaks on site. Through indoor tests, it is found that the embodiment of indoor plugging 1mm can treat small leaks on site (leakage rate ≤10m 3 / h), indoor plugging 2-3mm embodiment to treat on-site leakage (leakage rate 10-30m 3 / h), indoor plugging 4-5mm embodiment to treat large leakage on site (leakage rate ≥30m 3 / h), the temperature resistance reaches 180℃, and the pressure bearing capacity of 1-5mm crack plugging test reaches 20MPa, which can effectively solve the technical problem of deep high-temperature drilling fluid leakage. DETAILED DESCRIPTION

[0019] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0020] Now, exemplary embodiments of the present invention are introduced. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments are not intended to limit the present invention.

[0021] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0022] Example 1 The present embodiment provides a high temperature resistant plugging agent, which is composed of the following components in weight percentage: 40-50% high temperature resistant rigid particles, 30-40% high temperature resistant elastic particles, 20-30% high temperature resistant sheet materials, and 1-10% high temperature resistant fiber materials. The high temperature resistant rigid particles are thermosetting epoxy resin particles.

[0023] The high temperature resistant elastic particles are one or both of elastic graphite particles and expanded graphite particles.

[0024] The high temperature resistant sheet material is one or both of mica flakes and vermiculite.

[0025] The high-resistance fiber material is one or two of basalt fiber, sepiolite fiber and calcium carbonate whisker.

[0026] The high temperature resistant rigid particles, high temperature resistant elastic particles and high temperature resistant sheet materials are all mixtures of two or more different particle sizes of 4-8 mesh, 8-10 mesh, 10-40 mesh and 40-160 mesh.

[0027] The anti-high fiber material has a diameter of 20-100 μm and a length of 3-12 mm.

[0028] The high-temperature resistant leak-proofing agent provided by the present invention has high-temperature resistant elastic particles with good temperature and pressure resistance, and the high-temperature resistant sheet material and high-temperature resistant fiber material have high strength, which can form a seal on the bridge plug, bridge and fill the gaps in the high-temperature resistant rigid particles. At the same time, due to its elasticity and plasticity, it can seal the effective flow area of ​​most of the gaps by deformation, thereby achieving leak plugging.

[0029] Example 2 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 40% high-temperature resistant rigid particles, 30% high-temperature resistant elastic particles, 25% high-temperature resistant sheet materials, and 5% high-temperature resistant fiber materials.

[0030] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, which are composed of 10-40 mesh and 40-160 mesh thermosetting epoxy resin particles, and the mass ratio of the two is 1:1; the high temperature resistant elastic particles are elastic graphite particles, which are composed of 10-40 mesh and 40-160 mesh elastic graphite particles, and the mass ratio of the two is 1:1; the high temperature resistant sheet material is mica flakes, which are composed of 10-40 mesh and 40-160 mesh mica flakes, and the mass ratio of the two is 1:1; the high temperature resistant fiber material is basalt fiber (diameter 30μm, length 3mm).

[0031] Among them, the preparation method of thermosetting epoxy resin particles: The thermosetting epoxy resin particles are cross-linked by epoxy resin E51 and m-phenylenediamine, wherein the mass ratio of epoxy resin E51 is 85% and the mass ratio of m-phenylenediamine is 15%. First, take the epoxy resin E51 and heat it at 50°C to make it thinner, then add m-phenylenediamine, stir it evenly and put it in an oven to heat and cure it. The curing conditions are: 80°C / 2h+150°C / 2h. After curing, take it out and crush it into particles of different particle sizes. Due to the chemical activity of the epoxy group, it can be opened by a variety of compounds containing active hydrogen, cured and cross-linked to form a network structure. Therefore, it is a thermosetting resin. Since the m-phenylenediamine curing agent is polymerized by a variety of compounds, the secondary curing of the product can be achieved. Due to the presence of a variety of high-temperature resistant active groups such as phenyl, the epoxy resin cured product has the characteristics of high temperature resistance and can work at a temperature of 200°C for a long time.

[0032] The preparation method of the high temperature resistant plugging agent is to uniformly mix the formulated amount of high temperature resistant rigid particles, high temperature resistant elastic particles, high temperature resistant sheet materials and high temperature resistant fiber materials.

[0033] Example 3 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 42% high-temperature resistant rigid particles, 33% high-temperature resistant elastic particles, 22% high-temperature resistant sheet materials, and 3% high-temperature resistant fiber materials.

[0034] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, which are composed of 10-40 mesh (20%, expressed as mass percentage, the same below) and 40-160 mesh (22%) thermosetting epoxy resin particles; the high temperature resistant elastic particles are expanded graphite particles, which are composed of 10-40 mesh (18%) and 40-160 mesh (15%) elastic graphite particles; the high temperature resistant flaky material is vermiculite flakes, which are composed of 10-40 mesh (10%) and 40-160 mesh (12%) vermiculite flakes; the high temperature resistant fiber material is sepiolite fiber (diameter 50μm, length 3mm).

[0035] Example 4 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 40% high-temperature resistant rigid particles, 35% high-temperature resistant elastic particles, 23% high-temperature resistant sheet materials, and 2% high-temperature resistant fiber materials.

[0036] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, which are composed of thermosetting epoxy resin particles of 8-10 mesh (10%), 10-40 mesh (15%), and 40-160 mesh (15%); the high temperature resistant elastic particles are expanded graphite particles, which are composed of elastic graphite particles of 8-10 mesh (10%), 10-40 mesh (10%), and 40-160 mesh (15%); the high temperature resistant flaky material is mica flakes, which are composed of mica flakes of 8-10 mesh (5%), 10-40 mesh (13%), and 40-160 mesh (5%), and the mass ratio of the two is 1:1; the high temperature resistant fiber material is basalt fiber (diameter 50μm, length 6mm).

[0037] Example 5 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 48% high-temperature resistant rigid particles, 30% high-temperature resistant elastic particles, 20% high-temperature resistant sheet materials, and 2% high-temperature resistant fiber materials.

[0038] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, which are composed of 8-10 mesh (10%), 10-40 mesh (23%) and 40-160 mesh (15%) thermosetting epoxy resin particles; the high temperature resistant elastic particles are a mixture of elastic graphite particles and expanded graphite particles, specifically 8-10 mesh elastic graphite particles (5%), 10-40 mesh expanded graphite particles (10%) and 40-160 mesh expanded graphite particles (15%); the high temperature resistant flaky material is mica flakes (8~10 mesh) 5%, mica flakes (10~40 mesh) 10%, and vermiculite flakes (40~160 mesh) 5%; the high temperature resistant fiber material is basalt fiber (diameter 50μm, length 6mm).

[0039] Example 6 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 40% high-temperature resistant rigid particles, 35% high-temperature resistant elastic particles, 22% high-temperature resistant sheet materials, and 3% high-temperature resistant fiber materials.

[0040] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, thermosetting epoxy resin particles (4-8 mesh) 10%, thermosetting epoxy resin particles (8-10 mesh) 5%, thermosetting epoxy resin particles (10-40 mesh) 10%, thermosetting epoxy resin particles (40-160 mesh) 15%, elastic graphite particles (4-8 mesh) 10%, expanded graphite particles (8-10 mesh) 5%, expanded graphite particles (10-40 mesh) 10%, expanded graphite particles (40-160 mesh) 10%, vermiculite flakes (4-8 mesh) 5%, mica flakes (8-10 mesh) 7%, mica flakes (10-40 mesh) 5%, vermiculite flakes (40-160 mesh) 5%, basalt fiber (diameter 80 μm, length 12 mm) 3%.

[0041] Example 7 Based on Example 1, this example provides a high-temperature resistant plugging agent, which is composed of the following components in weight percentage: 45% high-temperature resistant rigid particles, 30% high-temperature resistant elastic particles, 20% high-temperature resistant sheet materials, and 3% high-temperature resistant fiber materials.

[0042] In this embodiment, the high temperature resistant rigid particles are thermosetting epoxy resin particles, thermosetting epoxy resin particles (4-8 mesh) 10%, thermosetting epoxy resin particles (8-10 mesh) 5%, thermosetting epoxy resin particles (10-40 mesh) 10%, thermosetting epoxy resin particles (40-160 mesh) 20%, expanded graphite particles (4-8 mesh) 10%, expanded graphite particles (8-10 mesh) 5%, elastic graphite particles (10-40 mesh) 5%, elastic graphite particles (40-160 mesh) 10%, vermiculite flakes (4-8 mesh) 5%, vermiculite flakes (8-10 mesh) 5%, mica flakes (10-40 mesh) 5%, mica flakes (40-160 mesh) 5%, basalt fiber (diameter 80 μm, length 12 mm) 2%, calcium carbonate whiskers (diameter 20 μm) 3%.

[0043] Comparative Example: A drilling fluid plugging formula, the following parts are by mass: walnut shell (4-8 mesh) 10%, walnut shell (8-10 mesh) 5%, walnut shell (10-40 mesh) 10%, walnut shell (40-160 mesh) 15%, elastic rubber (4-8 mesh) 10%, elastic rubber (8-10 mesh) 5%, elastic rubber (10-40 mesh) 10%, elastic rubber (40-160 mesh) 10%, plastic paper (4-8 mesh) 5%, plastic paper (8-10 mesh) 7%, plastic paper (10-40 mesh) 5%, plastic paper (40-160 mesh) 5%, polypropylene fiber (diameter 80μm, length 12mm) 3%.

[0044] Performance Testing The high temperature resistant plugging agents prepared in Examples 2-7 and the plugging formulations of the comparative examples were tested for their temperature resistance and crack sealing performance, and the methods are as follows: 1. Mass loss rate of high temperature aging: Prepare 500 ml of drilling fluid: 4% bentonite slurry + 0.4% CMC (sodium carboxymethyl cellulose, commercially available product) + 2% SPNH (lignite resin, commercially available product) + 2% SMP (sulfonated phenolic resin, commercially available product) + 4% ultrafine calcium carbonate. Add 10% by mass of plugging agent to the drilling fluid respectively, and stir evenly at 8000 rpm. Put the experimental slurry into a high-temperature aging tank, heat-roll aging at 180°C for 16 hours, and weigh the sample mass after sieving and drying, recorded as m2.

[0045] (1) Where: M——mass loss rate, %; m1——mass of sample before aging, g; m2——mass of sample after aging, g.

[0046] (2) Compressive strength of high temperature aging: Prepare 500 ml of drilling fluid: 4% bentonite slurry + 0.4% CMC + 2% SPNH + 2% SMP + 4% ultrafine calcium carbonate. Add 10% plugging agent to the drilling fluid respectively, and stir evenly at 8000 rpm. Put the experimental slurry into the high-temperature aging tank, hot roll aging at 180℃ for 16h, pressurize it with 30MPa, stabilize the pressure for 30min, and then screen it through a 160-mesh sieve to calculate the crushing rate.

[0047] Η=m3 / m4(2) Where: H——crushing rate, %; m3——mass passing through 160 mesh sieve, g; m4——total mass of the sample, g.

[0048] (3) Crack sealing pressure bearing capacity: Prepare 500 ml of drilling fluid: 4% bentonite slurry + 0.4% CMC + 2% SPNH + 2% SMP + 4% ultrafine calcium carbonate. Add 20% plugging agent to the drilling fluid respectively, and stir evenly at 8000 rpm. Use high temperature and high pressure dynamic plugging simulation experimental device, heat to 180℃, pour the prepared plugging slurry into the device, evaluate the plugging ability of the plugging slurry for cracks with different openings of 1mm, 2mm, 3mm, 4mm, 5mm, etc., and record the pressure strength and leakage.

[0049] The evaluation results of the embodiments are shown in Table 1 and Table 2 below: Table 1 Mass loss rate of high temperature aging in the examples It can be seen from Table 1 that after high-temperature aging at 180°C, the mass loss rate is less than 2.5%, and almost no mass loss occurs. The plugging agent still maintains its original appearance and has excellent resistance to 180°C.

[0050] Table 2 Compressive strength of high temperature aging of examples It can be seen from Table 2 that after high-temperature aging at 180°C, the compressive crushing rate is less than 4.0%. After high-temperature aging, it still maintains good temperature resistance and has excellent mechanical properties at 180°C.

[0051] Table 3 Crack sealing ability of examples after high temperature aging It can be seen from Table 3 that the pressure bearing capacity of 180℃ high-temperature cracks reaches 20MPa. (The reason why the pressure bearing capacity in Table 3 is 20MPa is that the plugging instrument can withstand a maximum of 20MPa. At this time, the instrument has reached its maximum limit and can still plug, so it is considered that the plugging pressure bearing capacity is 20MPa.) Example 2-7 can successfully plug cracks with different openings of 1-5mm, with large pressure bearing capacity and small leakage.

[0052] In summary, the high-temperature resistant plugging formula of the present invention can be selectively used for small leaks, medium leaks and large leaks with different crack openings. It has a temperature resistance of 180°C and a pressure bearing capacity of 20MPa, and is expected to solve the technical problem of plugging leaks in deep and ultra-deep high-temperature formations.

[0053] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A high temperature resistant plugging agent, characterized in that: The invention is composed of the following components in weight percentage: 40-50% of high temperature resistant rigid particles, 30-40% of high temperature resistant elastic particles, 20-30% of high temperature resistant sheet materials, and 1-10% of high temperature resistant fiber materials.

2. The high temperature resistant plugging agent according to claim 1, characterized in that: The high temperature resistant rigid particles are thermosetting epoxy resin particles.

3. The high temperature resistant plugging agent according to claim 1, characterized in that: The high temperature resistant elastic particles are one or both of elastic graphite particles and expanded graphite particles.

4. The high temperature resistant plugging agent according to claim 1, characterized in that: The high temperature resistant sheet material is one or both of mica flakes and vermiculite.

5. The high temperature resistant plugging agent according to claim 1, characterized in that: The high-resistance fiber material is one or two of basalt fiber, sepiolite fiber and calcium carbonate whisker.

6. The high temperature resistant plugging agent according to claim 1, characterized in that: The high temperature resistant rigid particles, high temperature resistant elastic particles and high temperature resistant sheet materials are all mixtures of two or more different particle sizes of 4-8 mesh, 8-10 mesh, 10-40 mesh and 40-160 mesh.

7. The high temperature resistant plugging agent according to claim 1, characterized in that: The anti-high fiber material has a diameter of 20-100 μm and a length of 3-12 mm.

8. The method for preparing a high temperature resistant plugging agent according to claim 1, characterized in that: The high temperature resistant rigid particles, high temperature resistant elastic particles, high temperature resistant sheet materials and high temperature resistant fiber materials are uniformly mixed to obtain the product.

9. Use of the high temperature resistant plugging agent according to claim 1 in plugging operations during drilling.

10. The use of a high temperature resistant plugging agent according to claim 9 in plugging operations during drilling, characterized in that: The dosage of high temperature resistant plugging agent is 10-20% of the drilling fluid mass.

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