Temperature-responsive cementing plugging composition for drilling pressure-bearing plugging, and preparation and use methods thereof

Abstract

The invention relates to a temperature response cementation plugging composition for drilling pressure-bearing plugging and a preparation method and a use method thereof.According to the plugging composition, the temperature sensitivity and oil / water resistance characteristics of a temperature response polymer are utilized, the retention capacity of plugging particles in cracks is enhanced, in addition, the particle size distribution range of the plugging particles is preferably selected, and the plugging performance of the plugging particles is improved. The plugging effect is further improved; existing gel type plugging materials can effectively plug cracks of 3 mm at the temperature of 150 DEG C and bear the plugging pressure of 9.8 MPa, and consolidation type plugging materials can bear the highest pressure of 14 MPa. Compared with the existing plugging materials, the plugging composition can effectively plug cracks of 5 mm at the temperature of 60-100 DEG C and bear the highest pressure of 28 MPa, and has the advantages of being higher in pressure bearing capacity and wider in crack plugging range. Therefore, the problem of drilling fluid leakage can be better solved.

Description

Technical Field

[0001] This disclosure relates to the field of oil drilling engineering technology, specifically to drilling pressure sealing materials. Background Technology

[0002] The statements in this section provide only background information in connection with this disclosure and do not constitute prior art.

[0003] Loss in wells is a phenomenon in which a large amount of drilling fluid leaks into the formation during drilling operations. It is one of the most common and difficult-to-handle complex accidents in drilling projects, especially in formations with well-developed fractures, fractured formations, or narrow or negative safety density windows. These formations often present serious problems such as leakage, leakage within the same formation, and loss of return.

[0004] When a loss occurs, the first step is to reduce the flow rate and observe the leakage rate. Then, depending on the extent of the loss, select appropriate plugging methods such as drilling-while-drilling plugging, static plugging, or solidification plugging to reduce drilling fluid loss until it stops. Generally, drilling-while-drilling plugging is used to handle low and moderate losses, while static plugging and solidification plugging are used to handle moderate, severe, and non-returnable losses.

[0005] Among them, static plugging particles, when used in fractured or broken formations that are sensitive to formation pressure, are affected by factors such as the gradation of the bridging material, the concentration of the bridging grout, and the displacement pressure during construction. This can easily lead to problems such as "sealing off," incomplete sealing, and repeated leakage, thus affecting the plugging efficiency. On the other hand, solidified plugging has a higher safety risk and is easily contaminated or diluted by high-mineralization formation water, resulting in poor retention capacity.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art. Summary of the Invention

[0007] In view of this, this disclosure provides a temperature-responsive cemented plugging composition for drilling pressure sealing and its preparation and application method, which solves the problem that static plugging particles are affected by multiple factors and fail to plug in cases of severe leakage and return leakage, while solidified plugging has a high construction safety risk.

[0008] The technical concept of the temperature-responsive cemented plugging composition for drilling pressure sealing of the present invention is as follows:

[0009] This composition consists of plugging particles and a temperature-responsive adhesive. The plugging particles include walnut shells, vermiculite, mica, graphite, calcium carbonate, and polyurethane foam. Different mesh sizes are selected according to the fracture opening. The walnut shells, vermiculite, mica, graphite, calcium carbonate, and polyurethane foam are used to bridge, trap, fill, and suspend the leakage channels, forming a tight-sealing layer. After well leakage occurs, the adhesive material also acts as a bridge before the response temperature is reached. After the response temperature is reached, the adhesive material takes effect, exhibiting an adhesive state, and adheres to the walnut shells, vermiculite, mica, polyurethane foam, graphite, and calcium carbonate, retaining the plugging particles, improving the plugging effect of the sealing layer, and avoiding "sealing the door," incomplete sealing, and repeated leakage accidents.

[0010] Based on the technical concept of this invention, and to achieve the above-mentioned objective, the temperature-responsive cemented plugging composition for drilling pressure sealing comprises:

[0011] Leak-sealing particles and temperature-responsive polymers;

[0012] After well leakage occurs, before reaching the response temperature, the polymer bridges the leakage channels. After reaching the response temperature, the polymer changes phase to liquid, which is used to adhere the plugging particles together to seal the leakage channels.

[0013] The response temperature corresponds to the bottom hole temperature.

[0014] In this disclosure and possible embodiments, the temperature-responsive polymer is a thermoplastic, rubber, or thermoplastic elastomer.

[0015] In this disclosure and possible embodiments, the thermoplastic is selected from one or more of ethylene vinyl acetate copolymer, polyethylene, polypropylene, polyurethane, polyamide, and polyacrylamide.

[0016] In this disclosure and possible embodiments, the thermoplastic elastomer is selected from one or more of thermoplastic polyurethane elastomers, styrene block thermoplastic elastomers, thermoplastic polyester elastomers, and thermoplastic polyolefin elastomers.

[0017] In this disclosure and possible embodiments, the rubber is nitrile rubber or silicone rubber.

[0018] In this disclosure and possible embodiments, particles with a diameter of W ≥ d > 2 / 3 W are used as end-capping particles, accounting for 10%; particles with a diameter of 2 / 3 W ≥ d ≥ 1 / 3 W are used as bridging particles, accounting for 65%; and particles with a diameter of d < 1 / 3 W are used as filler particles, accounting for 25%; wherein W is the width of the leakage channel.

[0019] In this disclosure and possible embodiments, the particle size distribution of the plugging particles satisfies W≥D90 ≥2 / 3W, D 25 ≥1 / 3W.

[0020] In this disclosure and possible embodiments, the plugging particles include walnut shells, vermiculite, mica, graphite, ultrafine calcium carbonate, and polyurethane foam.

[0021] In this disclosure and possible embodiments, the particle size of the walnut shell, vermiculite and mica is 2-40 mesh, the particle size of the graphite and ultrafine calcium carbonate is 400-800 mesh and 800-1250 mesh respectively, and the volume of the polyurethane foam is 0.25-0.5mm × 0.25-0.5mm × 0.25-0.5mm.

[0022] In a second aspect, a method for preparing the temperature-responsive cemented plugging composition for drilling pressure sealing as described in any one of the first aspects, characterized in that it comprises:

[0023] The sealing particles are mixed with a temperature-responsive polymer to obtain the sealing composition.

[0024] Thirdly, the method of using the temperature-responsive cemented plugging composition for drilling pressure sealing as described in any one of the first aspects includes:

[0025] Select temperature-responsive polymers based on bottom hole temperature and whether the drilling fluid system is oily or watery;

[0026] Select the plugging particles based on the width of the leakage channel.

[0027] In this disclosure and possible embodiments, for oil-based drilling fluid systems with a bottom-hole temperature above 60°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; for water-based drilling fluid systems with a bottom-hole temperature of 80-100°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; and for water-based drilling fluid systems with a bottom-hole temperature above 100°C, the temperature-responsive polymer is selected as thermoplastic elastomer.

[0028] The beneficial effects of this invention are as follows:

[0029] This disclosure discloses a temperature-responsive cemented plugging composition for drilling pressure sealing. It utilizes the temperature sensitivity and oil / water resistance of temperature-responsive polymers to enhance the retention capacity of plugging particles in fractures. Furthermore, the optimized particle size distribution further improves the sealing effect. Existing cementitious plugging materials can effectively seal 3mm fractures at 150℃ with a sealing pressure of 9.8MPa, while solidified plugging materials have a maximum pressure resistance of 14MPa. Compared to these materials, the plugging composition of this invention can effectively seal 5mm fractures at 60–100℃ with a maximum pressure resistance of 28MPa. Therefore, the temperature-responsive cemented plugging composition of this invention has higher pressure resistance, seals a wider range of fractures, and can better solve drilling fluid loss problems. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0031] Figure 1.1 , 1.2 Figure 1.3 shows the viscoelastic transition state diagrams of the temperature-responsive adhesive material in Example 1 in air, oil, and plugging particles, respectively.

[0032] Figure 2.1 , 2.2 Figures 2 and 2.3 show the front, back, and cross-sectional views of the sealing composition of Example 1 in an artificial wedge-shaped gap (3mm), respectively.

[0033] Figure 3 The sealing condition of the sealing composition of Example 1 in a wedge-shaped joint plate (1-3 mm);

[0034] Figure 4 The sealing condition of the sealing composition of Example 1 in a wedge-shaped joint plate (3-5 mm). Detailed Implementation

[0035] The present disclosure is described below based on embodiments; however, it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, certain specific details are described in detail. However, those skilled in the art will fully understand the present disclosure for the parts not described in detail.

[0036] Furthermore, unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to."

[0037] The temperature-responsive cemented plugging composition for well pressure sealing disclosed in this embodiment includes plugging particles and a temperature-responsive polymer. After well leakage occurs, before reaching the response temperature, the polymer acts as a bridging agent in the leakage channel. After reaching the response temperature, the polymer changes phase to liquid. Because the liquid polymer is in an adhesive state, it can adhere the plugging particles in the leakage channel together, causing the plugging material to remain in the leakage channel and improving the sealing effect of the plugging particles on the leakage channel. The response temperature of the temperature-responsive polymer corresponds to the bottom hole temperature.

[0038] In one specific embodiment, the temperature-responsive polymer is one of thermoplastics, rubber, and thermoplastic elastomers. Thermoplastics have linear or branched, uncrosslinked macromolecular chains that are solid at room temperature but melt into a viscous liquid at high temperatures. When bonding adherends, the polymer chain segments wet the adherends through diffusion, entanglement, etc., and then solidify upon cooling. Rubber and thermoplastic elastomers possess excellent toughness and elongation; they do not completely melt under high-temperature conditions, resulting in relatively low bonding strength but excellent flexibility.

[0039] In one specific embodiment, the thermoplastic is selected from one or more of ethylene-vinyl acetate copolymer, polyethylene, polypropylene, polyurethane, polyamide, and polyacrylamide. The thermoplastic elastomer is selected from one or more of thermoplastic polyurethane elastomer, styrene-block thermoplastic elastomer, thermoplastic polyester elastomer, and thermoplastic polyolefin elastomer. The rubber is nitrile rubber or silicone rubber.

[0040] In one specific embodiment, the plugging particles include walnut shells, vermiculite, mica, graphite, ultrafine calcium carbonate, and polyurethane foam. They bridge, trap, fill, and suspend in the leakage channels, residing in the leakage channels to form a tight-sealing plug layer.

[0041] In one specific embodiment, the particle size of the walnut shell, vermiculite, and mica is 2-40 mesh, the particle size of the graphite and ultrafine calcium carbonate is 800 mesh and 1250 mesh, i.e. 15μm and 10μm, and the volume of the polyurethane foam is 0.5mm×0.5mm×0.5mm.

[0042] According to the "Formation Mechanism of Fracture Sealing Layer and Optimal Selection Rules for Leakage Particles" in this field, where W represents the width of the leakage channel, leakage particles with a diameter satisfying 2 / 3W ≥ d ≥ 1 / 3W exhibit good sealing effect and can be used as bridging particles in the sealing layer. Particles with a diameter satisfying d < 1 / 3W have virtually no pressure-bearing capacity and can be used as filler particles in the sealing layer. Particles with a diameter satisfying W ≥ d > 2 / 3W have high pressure-bearing capacity at the fracture ends and can be used as end-capping particles. Based on this optimization rule, the proportions of bridging particles, filler particles, and end-capping particles in fractured formation leakage sealing particles should be 65%, 25%, and 10%, respectively. That is, the particle size and proportion of the leakage sealing particles should be selected as follows: 10% end-capping particles (W ≥ d > 2 / 3W), 65% bridging particles (2 / 3W ≥ d ≥ 1 / 3W), and 25% filler particles (d < 1 / 3W). In other words, when the particle size distribution satisfies W ≥ D... 90 ≥2 / 3W, D 25 When the pressure is ≥1 / 3W, a sealing layer with high pressure resistance can be formed, wherein: D 90 This indicates that the particles account for 90% of the total. 25 This indicates that the particles account for 25%.

[0043] In this embodiment of the present disclosure, the method for preparing the temperature-responsive cemented plugging composition for drilling pressure sealing involves mixing plugging particles with a temperature-responsive polymer to obtain the plugging composition.

[0044] In this embodiment of the disclosure, the method of using the temperature-responsive cemented plugging composition for drilling pressure sealing involves selecting a temperature-responsive polymer based on the bottom hole temperature and the oiliness or wateriness of the drilling fluid system; and selecting plugging particles based on the width of the leakage channel.

[0045] In one specific embodiment, for the oil-based drilling fluid system with a bottom-hole temperature above 60°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; for the water-based drilling fluid system with a bottom-hole temperature of 80-100°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; and for the water-based drilling fluid system with a bottom-hole temperature above 100°C, the temperature-responsive polymer is selected as thermoplastic elastomer.

[0046] In this disclosure, the experimental procedures for the temperature-responsive cemented plugging composition for drilling pressure sealing described in each embodiment are as follows:

[0047] 1. Experimental apparatus:

[0048] Electronic balances, slurry mixing machines, variable frequency high-speed mixers, crack sealing devices, high-temperature and high-pressure leak sealing devices, etc.

[0049] 2. Experimental steps:

[0050] (1) Prepare 5% on-site water-based soil slurry or oil-based drilling fluid slurry, add the specified type and amount of plugging particles, and stir with a variable frequency high-speed mixer for 20 minutes.

[0051] (2) Use a crack sealing instrument or a high-temperature and high-pressure leak sealing instrument to determine the leakage of the sealing grout under different crack width conditions.

[0052] The following are some preferred embodiments of this disclosure.

[0053] Example 1

[0054] 1. Preparation of Temperature-Response Cemented Plugging Composition for Well Pressure Sealing

[0055] Walnut shells, mica, polyurethane foam, graphite, ultrafine calcium carbonate, and TPE were weighed out in a mass ratio of 35:10:1:2:2:40 and added to the slurry. The mixture was stirred at 8000 r / min for 20 min to prepare the temperature-responsive cemented plugging composition for well pressure sealing in Example 1 of this invention.

[0056] 2. Leakage plugging effect test of the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 1.

[0057] (1) Thermoplastic elastomer (TPE) was placed in air, oil, and plugging particles respectively. When the aging temperature reached the response temperature, the functional adhesive material changed from a granular state to a molten state, and in air and oil, it became a gel and could bond with the plugging particles, such as... Figure 1.1 , 1.2 As shown in 1.3, when TPE is placed in air, oil and plugging particles, when the aging temperature reaches the response temperature, TPE changes from granular to molten state, and becomes gel in air and oil, and can adhere to the plugging particles.

[0058] (2) A plugging test was conducted on the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 1 with a crack width of 1-5 mm at a test temperature of 100℃. The results are shown in Table 1. Figure 2.1 , 2.2 2.3 Figure 3 and Figure 4 :

[0059] Table 1. Plugging Effect of Temperature-Response Cemented Plugging Composition for Drilling Pressure Sealing

[0060]

[0061] Note: The crack sealing instrument uses an artificial wedge-shaped crack, and the test temperature is room temperature; the high-temperature and high-pressure leak sealing instrument uses a wedge plate, and the test temperature is 60-100℃.

[0062] Table 1 shows that the temperature-responsive cemented plugging composition for well pressure sealing can effectively seal cracks within 5 mm.

[0063] like Figure 2.1 , 2.2 2.3 and Figure 3 As shown, the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 1 was placed in the artificial wedge-shaped slot of the fracture plugging instrument for a plugging simulation experiment. It can be seen that the plugging particles enter the fracture and have a certain stroke, without the "sealing" phenomenon, and the plugging effect is good.

[0064] like Figure 4 As shown, the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 1 was placed in the wedge-shaped slot of a high-temperature and high-pressure plugging instrument for plugging simulation experiments. It can be seen that the plugging particles enter the crack and have a certain stroke, without the "sealing" phenomenon, and some plugging particles soften, indicating a good sealing effect.

[0065] Example 2

[0066] 1. Preparation of Temperature-Response Cemented Plugging Composition for Well Pressure Sealing

[0067] According to the mass ratio of 35:10:1:2:2:40, vermiculite, mica, polyurethane foam, graphite, ultrafine calcium carbonate and EVA were weighed and added to the soil slurry. The mixture was stirred at 8000 r / min for 20 min to prepare the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 2.

[0068] 2. Leakage plugging effect test of the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 2.

[0069] A sealing experiment was conducted on the temperature-responsive cemented sealing composition for drilling pressure sealing of Example 2 with a crack width of 1-5 mm at an experimental temperature of 80°C. The experimental results are shown in Table 1. As can be seen from Table 1, the temperature-responsive cemented sealing composition for drilling pressure sealing of Example 2 can form a good seal for cracks within 5 mm.

[0070] Example 3

[0071] 1. Preparation of Temperature-Response Cemented Plugging Composition for Well Pressure Sealing

[0072] Walnut shells, mica, polyurethane foam, graphite, ultrafine calcium carbonate, and EVA were weighed out in a mass ratio of 35:10:1:2:2:40 and added to oil-based drilling fluid. The mixture was stirred at 12,000 r / min for 20 min to prepare the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 3.

[0073] 2. Leakage plugging effect test of the temperature-responsive cemented plugging composition for drilling pressure sealing in Example 3.

[0074] A sealing experiment was conducted on the temperature-responsive cemented plugging composition for drilling pressure sealing of Example 3 with a crack width of 1-5 mm at an experimental temperature of 60°C. The experimental results are shown in Table 1. As can be seen from Table 1, the temperature-responsive cemented plugging composition for drilling pressure sealing of Example 3 can form a good seal for cracks within 5 mm in oil-based drilling fluid.

[0075] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A temperature-responsive cemented plugging composition for drilling pressure sealing, characterized in that, include: Leak-sealing particles and temperature-responsive polymers; After well leakage occurs, before reaching the response temperature, the polymer bridges the leakage channels. After reaching the response temperature, the polymer changes phase to liquid, which is used to adhere the plugging particles together to seal the leakage channels. The response temperature corresponds to the bottom hole temperature.

2. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 1, characterized in that: The temperature-responsive polymer is a thermoplastic, rubber, or thermoplastic elastomer.

3. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 2, characterized in that: The thermoplastic is selected from one or more of ethylene-vinyl acetate copolymer, polyethylene, polypropylene, polyurethane, polyamide, and polyacrylamide.

4. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 2, characterized in that: The thermoplastic elastomer is selected from one or more of thermoplastic polyurethane elastomers, styrene block thermoplastic elastomers, thermoplastic polyester elastomers, and thermoplastic polyolefin elastomers.

5. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 2, characterized in that: The rubber is nitrile rubber and silicone rubber.

6. The temperature-responsive cemented plugging composition for drilling pressure sealing according to any one of claims 1-5, characterized in that: In the plugging particles, particles with a diameter of W ≥ d > 2 / 3 W are used as end-capping particles, accounting for 10%; particles with a diameter of 2 / 3 W ≥ d ≥ 1 / 3 W are used as bridging particles, accounting for 65%; and particles with a diameter of d < 1 / 3 W are used as filler particles, accounting for 25%; where W is the width of the leakage channel.

7. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 6, characterized in that: The particle size distribution of the plugging particles satisfies W≥D 90 ≥2 / 3W, D 25 ≥1 / 3W.

8. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 7, characterized in that: The plugging particles include walnut shells, vermiculite, mica, graphite, ultrafine calcium carbonate, and polyurethane foam.

9. The temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 8, characterized in that: The walnut shells, vermiculite, and mica have a particle size of 2–40 mesh, the graphite and ultrafine calcium carbonate have a particle size of 400–800 mesh and 800–1250 mesh, and the polyurethane foam has a volume of 0.25–0.5 mm × 0.25–0.5 mm × 0.25–0.5 mm.

10. A method for preparing the temperature-responsive cemented plugging composition for drilling pressure sealing according to any one of claims 1-9, characterized in that, include: The sealing particles are mixed with a temperature-responsive polymer to obtain the sealing composition.

11. A method of using the temperature-responsive cemented plugging composition for drilling pressure sealing according to any one of claims 1-9, characterized in that, include: Select temperature-responsive polymers based on bottom hole temperature and whether the drilling fluid system is oily or watery; Select the plugging particles based on the width of the leakage channel.

12. The method of using the temperature-responsive cemented plugging composition for drilling pressure sealing according to claim 11, characterized in that: For oil-based drilling fluid systems with a bottom-hole temperature above 60°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; for water-based drilling fluid systems with a bottom-hole temperature of 80-100°C, the temperature-responsive polymer is selected as ethylene-vinyl acetate copolymer; and for water-based drilling fluid systems with a bottom-hole temperature above 100°C, the temperature-responsive polymer is selected as thermoplastic elastomer.

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