High temperature resistant lost circulation material and method of making

Abstract

The application provides an anti-high-temperature plugging agent and a preparation method thereof. The plugging agent is mixed by a plurality of raw materials, and the raw materials include a resin matrix and a mineral powder filler. The resin matrix is 55-75 parts by weight, and the mineral powder filler is 25-45 parts by weight, based on 100 parts by weight of the plugging agent. The method is that the base materials are mixed at normal temperature, then high-temperature hot-pressing forming is carried out, and then normal-temperature granulation is carried out to obtain the anti-high-temperature plugging agent. The density of the plugging agent is between 1.4-2.2 g / cm 3 , the plugging agent is easily stably suspended in the plugging slurry, and the difficulty of preparation of the plugging slurry can be reduced. The preparation method is simple, the base materials are widely sourced, the prepared plugging agent has a temperature resistance capacity of greater than or equal to 150 DEG C, and a compressive strength of greater than or equal to 30 MPa.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling engineering, and more specifically, to a high-temperature resistant plugging agent and its preparation method. Background Technology

[0002] As oil and gas drilling moves into deeper and more complex blocks and formations, the formation pressure systems encountered become increasingly complex. When well leakage occurs in formations with different pressure systems, it is necessary to use drilling fluid densities that match the pressure systems. When preparing plugging slurries of different densities, it is necessary to select plugging materials that match their densities.

[0003] Currently, the most commonly used natural rigid sealing materials are mineral particles and plant shell particles. Among them, mineral sealing materials such as calcite particles have a density of approximately 2.6 g / cm³. 3 The density of nutshell-based sealing materials, such as walnut shells, is approximately 1.2 g / cm³. 3 The density of the sealing slurry is approximately [not specified]. When the density of the sealing slurry is low, the introduction of mineral-based rigid sealing agents can easily cause the system to settle, severely affecting the sealing effect. On-site, in order to improve the settling stability of mineral-based rigid sealing agents, the viscosity and shear force of the slurry are often increased, but this increases the difficulty of preparing the sealing slurry and makes pumping difficult. When the density of the sealing slurry is high, plant-based sealing agents are prone to floating, affecting the sealing effect.

[0004] The patent document "An Organic Synthetic Positive Pressure Particle for Drilling and Its Preparation Method" discloses a method for preparing organic synthetic positive pressure particles. The particles are composed of one or more of calcium carbonate whiskers, magnesium borate whiskers, and calcium sulfate whiskers, blended with polyetheretherketone (PEEK) and polyetherimide (PEI). The preparation method involves melting and extruding at 380°C, cooling, drying, and granulation. This technical solution has several drawbacks: (1) The preparation method is complex, requiring specialized equipment for high-temperature mixing above 380°C, resulting in high energy consumption and difficulty in operation; (2) The resin material is PEEK and PEI, and the filler is one or more of calcium carbonate whiskers, magnesium borate whiskers, and calcium sulfate whiskers, making the basic materials scarce and costly; (3) The prepared positive pressure particles have a temperature resistance of only 120°C, which cannot meet the requirements for rigid particles in high-temperature deep well plugging with downhole temperatures greater than 150°C. Currently, there is a lack of high-strength, medium-density (1.4-2.2 g / cm³) particles with a temperature resistance ≥150°C. 3 Rigid sealant.

[0005] Therefore, researching a medium-density, high-strength, high-temperature resistant sealing agent has significant application value. Summary of the Invention

[0006] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to address the problems of existing granular sealants having excessively high density leading to sedimentation and excessively low density leading to floating. Another objective of this invention is to address the shortcomings of existing granular sealants having insufficient medium-strength sealing strength and low temperature resistance. A third objective of this invention is to provide a solution that improves the preparation efficiency of sealant slurry.

[0007] To achieve the above objectives, the present invention provides a high-temperature resistant sealing agent, which is composed of a mixture of various raw materials, including a resin matrix and mineral powder fillers.

[0008] Based on 100 parts by weight of the sealant, the resin matrix is ​​55 to 75 parts by weight, and the mineral powder filler is 25 to 45 parts by weight.

[0009] Alternatively, the resin matrix is ​​obtained by compounding melamine resin and epoxy resin in a mass ratio of 50-90:10-50.

[0010] Alternatively, the mineral powder filler may comprise a combination of quartz powder and ultrafine calcium carbonate.

[0011] Alternatively, the particle size of the mineral powder filler is 40–100 μm.

[0012] Another aspect of the present invention provides a method for preparing a high-temperature resistant sealing agent, wherein the sealing agent is the aforementioned sealing agent, and the method includes the following steps:

[0013] Under stirring conditions, the resin matrix and the mineral powder filler are mixed in one step to form a mixture;

[0014] The mixture is hot-pressed at 180–200°C to obtain the base material for the sealant.

[0015] The base material of the sealant is granulated to obtain the high-temperature resistant sealant.

[0016] Alternatively, the stirring speed is 50-100 rpm and the stirring time is 30-45 minutes.

[0017] Alternatively, the hot pressing time is 15 to 30 minutes.

[0018] Alternatively, the hot pressing conditions may also include a hot pressing pressure of 10–30 MPa.

[0019] Alternatively, the granulation process may employ a granulator including a hammer crusher, jaw crusher, or roller crusher.

[0020] Optionally, the density of the high-temperature resistant sealing agent ranges from 1.4 to 2.2 g / cm³. 3Compressive strength ≥30MPa, temperature resistance ≥150℃.

[0021] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0022] 1) The density of the sealant of this invention is between 1.4 and 2.2 g / cm³. 3 It is easy to remain stably suspended in the sealing grout, which can reduce the difficulty of preparing the sealing grout.

[0023] 2) Existing synthetic rigid plugging particles have complex preparation processes, limited sources of basic materials, high costs, and temperature resistance ≤120℃. The technical solution provided by this invention uses a composite resin material with strong temperature resistance as the matrix and compounded mineral powder as the filler. The preparation method is simple, the sources of basic materials are wide, and the prepared plugging agent has a temperature resistance ≥150℃.

[0024] 3) The sealing agent prepared by this invention has a compressive strength ≥30MPa. Detailed Implementation

[0025] The high-temperature sealing agent and its preparation method of the present invention will be described in detail below with reference to exemplary embodiments.

[0026] Exemplary Example 1

[0027] This exemplary embodiment provides a high-temperature resistant sealant, which is composed of a mixture of various raw materials, including a resin matrix and mineral powder fillers; 100 parts by weight of the sealant

[0028] Based on this, the resin matrix is ​​55-75 parts by weight, and the mineral powder filler is 25-45 parts by weight. For example, the weight of the resin matrix can be 56, 65, 70, or 74 parts, and the weight of the mineral powder filler can be 26, 37, 40, or 44 parts, etc., which can achieve the control of the density of the sealing material.

[0029] In this embodiment, the resin matrix is ​​obtained by compounding melamine resin and epoxy resin in a mass ratio of 50-90:10-50. This ratio allows for adjustment of the strength of the sealing material. The mineral powder filler comprises a combination of quartz powder and ultrafine calcium carbonate, with a compounding ratio of quartz powder to ultrafine calcium carbonate of 50-75:25-50; the particle size of the mineral powder filler can be 40-100 μm. Adjusting the compounding ratio of quartz to ultrafine calcium carbonate is beneficial for adjusting the strength of the sealing material; controlling the particle size of the mineral powder filler is beneficial for controlling the strength and temperature resistance of the sealing material.

[0030] Exemplary Example 2

[0031] This exemplary embodiment provides a method for preparing a high-temperature resistant sealant, wherein the high-temperature resistant sealant is the sealant described in Exemplary Embodiment 1, and the preparation method includes the following steps:

[0032] S01: Under stirring conditions, the resin matrix and the mineral powder filler are mixed in one step to form a mixture.

[0033] In this embodiment, stirring can be carried out at room temperature, mixing the resin matrix and the mineral powder filler in one step to form a mixture. The stirring speed is 50-100 rpm, and the stirring time is 30-45 minutes.

[0034] S02: The mixture is hot-pressed at 180-200℃ to obtain the base material of the sealant.

[0035] In this embodiment, the mixture can be hot-pressed on a flatbed hot press. The hot-pressing temperature can be 180-200°C, the pressure can be 10-30 MPa, and the hot-pressing time can be 15-30 minutes. The above hot-pressing temperature is conducive to the thermoplastic deformation of the resin powder, the pressure range is convenient for controlling the strength of the sealing material, and the hot-pressing time range is conducive to the full fusion and molding of the mixture.

[0036] S03: Granulate the base material of the sealing agent to obtain the high-temperature resistant sealing agent.

[0037] In this embodiment, the base material of the sealing agent is granulated in a granulator to obtain granular high-temperature resistant sealing agent. The granulator can be a hammer mill, jaw mill, or roller mill, etc. The density range of the obtained high-temperature resistant sealing agent can be 1.4–2.2 g / cm³. 3 The plugging agent exhibits excellent settling stability in plugging slurries of different density ranges, facilitating the preparation of plugging slurries; the high-temperature resistant plugging agent has a compressive strength of ≥30MPa and a temperature resistance of ≥150℃, meeting the requirements of high-temperature deep wells for the density, strength, and temperature resistance of rigid plugging agents.

[0038] To better understand the exemplary embodiments of the present invention described above, further explanation is provided below with reference to specific examples.

[0039] Example 1

[0040] This example provides a high-temperature resistant sealant, with the following raw materials in the following weight proportions: 30 parts melamine resin powder, 30 parts epoxy resin, 20 parts quartz powder, and 20 parts ultrafine calcium carbonate. The aforementioned raw materials are added to a high-speed mixer and mixed at 90 rpm for 10–30 minutes at room temperature. The mixture is then removed, spread evenly in a high-temperature hot press mold, and hot-pressed at 200°C and 30 MPa for 30 minutes. After depressurization, cooling, and demolding, the sealant base material is obtained. This base material is then placed in a hammer mill, and the mill is turned on and granulated to obtain granular sealant material. After sieving using a vibrating screen, sealants of different particle sizes are obtained. The density of the sealant product is 1.82 g / cm³. 3 The mass loss rate at 150℃ was 3.24%, and the breakage rate under 30MPa pressure was 5.80%.

[0041] The test standards or methods for the performance parameters of the high-temperature resistant sealant are as follows:

[0042] Temperature resistance test method:

[0043] Weigh 100g of the sample (e.g., for particles with a size of 1.00mm to 1.20mm, take the sieve residue that passes through a 1.20mm sieve but not a 1.00mm sieve) (accurate to 0.01g), and record it as m. Place it in a high-temperature aging tank, add 250mL of water, seal it, and place it in a high-temperature roller heating furnace. After aging at 150℃ for 16 hours, cool and open the tank, wash the particles, dry it at 105℃, remove the sample, and pass it through a lower limit sieve (e.g., for particles with a size of 1.00mm to 1.20mm, the lower limit sieve is a 1.00mm sieve) until no particles pass through. Weigh the sieve residue and record it as m1. Mass loss rate S T ≤10% is considered heat resistant to 150℃.

[0044]

[0045] Test method for pressure breakage rate:

[0046] Weigh 100g (accurate to 0.01g) of the sample (e.g., for particles with a size of 1.00mm to 1.20mm, take the sample remaining after passing through a 1.20mm sieve but not a 1.00mm sieve), and record it as m. Add the sample to a pressure cup (placed on the base plate) and smooth it out. Then add the piston column, place it on a press, and pressurize it at a uniform rate to 30MPa. Maintain the pressure for 10 minutes, then release the pressure, remove the sample, and pass it through a lower limit sieve (e.g., for particles with a size of 1.00mm to 1.20mm, the lower limit sieve is a 1.00mm sieve) until no particles pass through. Weigh the residue and record it as m2.

[0047] Pressure breakage rate S P ≤10% is considered to be resistant to 30MPa.

[0048]

[0049] Example 2

[0050] This example provides a high-temperature resistant sealant, with the following raw materials in the following weight proportions: 21 parts melamine resin powder, 21 parts epoxy resin, 29 parts quartz powder, and 29 parts ultrafine calcium carbonate. The aforementioned raw materials are added to a high-speed mixer and mixed at 90 rpm for 10–30 minutes at room temperature. The mixture is then removed, spread evenly in a high-temperature hot press mold, and hot-pressed at 200°C and 30 MPa for 30 minutes. After pressure release, cooling, and demolding, the sealant base material is obtained. This base material is then placed in a hammer mill, and the mill is turned on and granulated to obtain granular sealant material. After sieving using a vibrating screen, sealants of different particle sizes are obtained. The density of the sealant product is 2.0 g / cm³. 3 The mass loss rate at 150℃ was 4.68%, and the breakage rate under 30MPa pressure was 6.40%.

[0051] Although the present invention has been described above in conjunction with exemplary embodiments, it should be clear to those skilled in the art that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A high-temperature resistant sealant, characterized in that, The sealing agent is composed of a mixture of various raw materials, including a resin matrix and mineral powder fillers; Based on 100 parts by weight of the sealant, the resin matrix is ​​55-75 parts by weight, and the mineral powder filler is 25-45 parts by weight. The resin matrix is ​​obtained by compounding melamine resin and epoxy resin in a mass ratio of 50~90:10~50; The mineral powder filler comprises a combination of quartz powder and ultrafine calcium carbonate, wherein the ratio of quartz powder to ultrafine calcium carbonate is 50-75:25-50.

2. The sealing agent according to claim 1, characterized in that, The particle size of the mineral powder filler is 40~100μm.

3. A method for preparing a high-temperature resistant sealing agent, characterized in that, The sealing agent is the sealing agent according to any one of claims 1-2, and the method includes the following steps: Under stirring conditions, the resin matrix and the mineral powder filler are mixed in one step to form a mixture; The mixture is hot-pressed at 180~200℃ to obtain the base material of the sealant; The base material of the sealant is granulated to obtain the high-temperature resistant sealant.

4. The preparation method according to claim 3, characterized in that, The stirring speed is 50-100 rpm, and the stirring time is 30-45 minutes.

5. The preparation method according to claim 3, characterized in that, The hot pressing time is 15-30 minutes.

6. The preparation method according to claim 3, characterized in that, The hot pressing conditions also include a hot pressing pressure of 10~30MPa.

7. The preparation method according to claim 3, characterized in that, The granulation process employs a granulator, including hammer crushers, jaw crushers, or roller crushers.

8. The preparation method according to claim 3, characterized in that, The density range of the high-temperature resistant sealing agent is 1.4~2.2 g / cm³. 3 Compressive strength ≥30MPa, temperature resistance ≥150℃.

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