Biodegradable fracturing diverting temporary plugging agent and preparation method thereof

Abstract

This invention discloses a biodegradable fracturing deflector and its preparation method, relating to the field of oil and gas field fracturing technology. By weight, it comprises the following raw material components: 55-65 parts of leather gelatin (denatured collagen matrix, mainly composed of type I collagen, hydrolyzed peptides, and gelatin); 10-12 parts of xanthan gum (microbial polysaccharide degradation regulator); 10-12 parts of tara gum (plant galactomannan binder modifier); 10-13 parts of konjac flour (bio-derived reinforcing filler particles); and 5-8 parts of hydroxypropyl starch (smoothing agent). All components of the HX101 deflector of this invention are derived from natural plant, animal, or microbial fermentation products. The matrix is ​​animal-derived denatured collagen, and the reinforcing components, binder, and regulator are all derived from natural biomass raw materials. Ultimately, it can be completely biodegraded into carbon dioxide and water, with a degradation rate exceeding 95%. It will not remain in the reservoir and cause permanent damage, and the reservoir permeability recovery value can reach over 90%.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field fracturing technology, specifically to a biodegradable fracturing deflection plugging agent and its preparation method, particularly to the biodegradable fracturing deflection plugging agent designated HX101. Background Technology

[0002] With the continuous deepening of oil and gas exploration and development in China, the enhancement and stimulation of unconventional oil and gas reservoirs and old oilfields has become one of the core directions of my country's oil and gas production capacity construction. Fracturing is a core technology for improving the production capacity of low-permeability oil and gas reservoirs and realizing repeated fracturing of old wells. Among the processes of multi-stage fracturing, fracture network fracturing, and repeated fracturing, temporary plugging and diversion technology is a key support for achieving effective fracture expansion and increasing the stimulation volume.

[0003] Traditional fracturing plugging agents are mainly classified into rigid particulate plugging agents, fiber plugging agents, and biodegradable polymer plugging agents. Rigid particulate plugging agents are mostly non-biodegradable materials such as quartz sand and ceramsite. After application, they remain in fractures and reservoir throats, making complete removal difficult and potentially causing permanent damage to the reservoir, reducing permeability, and impacting final oil and gas production. Fiber plugging agents rely on entanglement and accumulation to form a plugging layer, but their plugging strength is insufficient to meet the plugging requirements of high-fracturing-pressure reservoirs. Furthermore, some synthetic fibers also present problems of difficult degradation and residual damage. Traditional biodegradable polymer plugging agents often use materials such as polylactic acid and polyvinyl alcohol. Their degradation rate is greatly affected by reservoir temperature and salinity; degradation is extremely slow in low-temperature reservoirs and prone to premature degradation in high-temperature reservoirs, making them unsuitable for the pace of fracturing operations. Additionally, the degradation products of some biodegradable materials can pollute reservoir fluids, failing to meet the requirements of green development.

[0004] While some bio-based biodegradable temporary plugging agents have been researched in the existing technology, they generally suffer from problems such as unstable biodegradability, insufficient temporary plugging strength, poor storage stability, and narrow applicable reservoir temperature range, making it difficult to meet the needs of fracturing and temporary plugging operations in different blocks and types of reservoirs in my country. Therefore, developing a novel biodegradable fracturing decoupling temporary plugging agent with controllable degradation, high temporary plugging strength, low reservoir damage, and environmental friendliness has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, this invention provides a biodegradable fracturing deflection plugging agent that solves the problems of unstable biodegradability, insufficient plugging strength, poor storage stability, and narrow applicable reservoir temperature range that exist in the prior art, which make it difficult to meet the needs of fracturing and plugging operations in different blocks and types of reservoirs in my country.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a biodegradable fracturing diversion plugging agent, comprising the following raw material components by weight: 55-65 parts of hide glue (denatured collagen matrix, mainly composed of type I collagen, hydrolyzed peptides, and gelatin), 10-12 parts of xanthan gum (microbial polysaccharide degradation regulator), 10-12 parts of tara gum (plant galactomannan binder modifier), 10-13 parts of konjac flour (bio-based enhanced filler particles), and 5-8 parts of hydroxypropyl starch (smoothing agent).

[0008] The gel matrix is ​​a denatured collagen matrix, mainly composed of type I collagen, compounded with hydrolyzed peptides and gelatin. The gel strength and temperature resistance of the material are adjusted through denaturation treatment, which solves the problems of poor temperature resistance and uncontrollable degradation rate of natural collagen.

[0009] Furthermore, the hide glue used in this invention is entirely derived from animal-derived biomass and has excellent biodegradability. After denaturation treatment, it can meet the temperature and pressure resistance requirements during fracturing operations. At the same time, the degradation rate can be controlled by adjusting the degree of denaturation to meet the construction requirements of different reservoirs.

[0010] The bio-based reinforced filler particles are konjac glucomannan composite plant crude fiber components provided by konjac powder, with a particle size distribution of 100-1000μm and an ash content of less than 3%. The plant crude fiber itself has a certain fiber skeleton structure, which can improve the strength of the temporary plugging layer formed after the temporary plugging agent particles are accumulated. At the same time, konjac powder is completely derived from natural plants, is biodegradable, and will not cause long-term residual damage to the reservoir. It can also adapt to cracks of different widths by adjusting the particle size distribution, thereby improving the adaptability of the temporary plugging.

[0011] The degradation regulator is xanthan gum, which is a microbial polysaccharide prepared by microbial fermentation. It can specifically induce microbial degradation activity and accelerate the overall degradation process of the temporary plugging agent. Xanthan gum itself can also be completely biodegraded without leaving any residue. By adjusting the amount of degradation regulator added, the degradation rate can be controlled and adjusted to meet the requirements of different construction cycles and different reservoir temperatures.

[0012] The adhesive modifier is tara gum, a plant-derived galactomannan, which can improve the bonding strength between the leather glue matrix and the bio-based reinforcing fibers, and prevent the temporary blockage agent particles from breaking during transportation. At the same time, tara gum itself is a natural plant-derived material that is completely biodegradable and environmentally friendly.

[0013] The lubricant is hydroxypropyl starch, a modified natural starch, which can improve the surface smoothness of the plugging agent particles, prevent premature bridging during injection, and ensure that the plugging agent can be smoothly delivered to the target layer to form an effective plug. At the same time, hydroxypropyl starch is biodegradable and will not produce pollution. As a preferred embodiment of the biodegradable fracturing diversion plugging agent of the present invention, the skin glue is a denatured animal-derived collagen with a denaturation degree controlled at 8%-12%, and the cross-linking density and temperature resistance of the collagen are adjusted by denaturation.

[0014] As a preferred embodiment of the biodegradable fracturing steering plugging agent of the present invention, wherein: the bio-based reinforcing filler particles are plant crude fiber components provided by konjac flour, with a particle size distribution of 100-1000μm and an ash content of less than 3%.

[0015] As a preferred embodiment of the biodegradable fracturing deflection plugging agent of the present invention, the degradation regulator is xanthan gum prepared by microbial fermentation, and the overall degradation rate of the plugging agent is controlled by adjusting the amount of xanthan gum added.

[0016] As a preferred embodiment of the biodegradable fracturing steering plugging agent of the present invention, the bonding modifier is galactomannan extracted from natural plants, namely tarara, which is used to improve the bonding strength between the matrix and the reinforcing component.

[0017] As a preferred embodiment of the biodegradable fracturing steering plugging agent of the present invention, the lubricant is hydroxypropyl starch, which is used to improve the injection smoothness of the plugging agent particles.

[0018] Secondly, the present invention provides a method for preparing a biodegradable fracturing diversion plugging agent, comprising: (1) Weigh each raw material according to the weight proportions, add the leather glue to deionized water, heat to 55-65℃ to swell and activate, keep warm and stir for 20-30 minutes to obtain the colloidal matrix; (2) Add xanthan gum, tara gum and konjac powder to the colloidal matrix in sequence, keep the temperature and stir for 15-20 minutes at a stirring speed of 300-500 r / min to obtain the mixture; (3) Cool the mixture to 35-45℃, add hydroxypropyl starch, continue stirring for 5-10 minutes, then extrude and granulate, vacuum dry and sieve to obtain HX101 biodegradable fracturing deflector plugging agent.

[0019] As a preferred embodiment of the preparation method of the biodegradable fracturing deflection temporary plugging agent of the present invention, the degradation rate of the HX101 biodegradable fracturing deflection temporary plugging agent is not less than 95%, the reservoir core permeability recovery value is not less than 90%, the applicable reservoir temperature range is 30-150℃, and the degradation cycle is controllable within the range of 3-15 days.

[0020] Beneficial effects of this invention: (1) All components of the HX101 temporary plugging agent of the present invention are derived from natural animal, plant or microbial fermentation products. The matrix is ​​animal-derived denatured collagen. The reinforcing components, binders and regulators are all derived from natural biomass raw materials. It can be completely biodegraded into carbon dioxide and water in the end. The degradation rate can reach more than 95%. It will not remain in the reservoir and cause permanent damage. The reservoir permeability recovery value can reach more than 90%, which is far superior to traditional non-degradable temporary plugging agents and meets the requirements of green development of oil and gas fields.

[0021] (2) By adjusting the crosslinking density of the leather matrix through denaturation and adjusting the amount of microbial xanthan gum added, the degradation rate can be adjusted according to the reservoir temperature and construction cycle. Within the reservoir temperature range of 30-150℃, the degradation time can be controlled and the degradation cycle can be controlled within 3-15 days, meeting the requirements of different construction processes and solving the problems of unstable degradation rate and poor compatibility of traditional biodegradable temporary plugging agents.

[0022] (3) The present invention uses natural plant coarse fiber as a reinforcing skeleton, combined with Tara glue bonding modification, the temporary plugging agent particles have high strength, and after injection into the formation, they can quickly accumulate at the fracture entrance to form a high-strength temporary plugging bridge. The temporary plugging breakthrough pressure can reach more than 35MPa, which can meet the temporary plugging requirements of high fracture pressure reservoirs, effectively realize the fracturing fluid diversion, expand the reservoir stimulation volume, and improve the production effect.

[0023] (4) The present invention uses a composite polysaccharide system to stabilize the colloidal structure, combined with hydroxypropyl starch surface modification. The temporary plugging agent has stable performance during room temperature dry storage, with an early degradation rate of less than 2% and a storage period of more than 12 months. It can be directly injected with the carrying liquid during construction without special construction process, is compatible with existing fracturing construction equipment, and has low application cost. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a flowchart of the preparation method of the biodegradable fracturing deflector plugging agent in Example 1. Detailed Implementation

[0026] To make the above-mentioned objectives, features and advantages of the present invention more readily understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments. Example 1

[0029] By weight, the raw material components are: 55 parts of hide gelatin (denatured collagen, mainly type I collagen, hydrolyzed peptides, and gelatin), 10 parts of xanthan gum, 10 parts of tara gum, 13 parts of konjac flour, and 8 parts of hydroxypropyl starch. The denaturation degree of the hide gelatin is 10%, the particle size distribution of the konjac flour is 200-800 μm, and the ash content is less than 3%.

[0030] Preparation method: (1) Weigh the leather glue and add it to deionized water, heat it to 60°C to swell and activate it, keep it warm and stir for 25 min to obtain the leather glue colloidal matrix; (2) Add xanthan gum, tara gum and konjac powder in sequence, keep it at 60°C and stir for 18 min at a speed of 400 r / min; (3) Cool it down to 40°C, add hydroxypropyl starch and stir for 8 min, extrude and granulate, vacuum dry at 40°C for 12 h, and sieve to obtain the HX101 temporary plugging agent finished product.

[0031] The performance of the HX101 temporary plugging agent prepared in this embodiment was tested: in simulated formation water at 90℃ and with a mineralization of 10×104 mg / L, the complete degradation time was 7 days, and the degradation rate reached 96.2%; after 12 months of storage under room temperature and dry conditions, the premature degradation rate was 1.3%; in the performance evaluation experiment, for an artificial fracture with a width of 2 mm, the temporary plugging breakthrough pressure reached 38 MPa, and the core permeability recovery value was 92.7%, which met the construction requirements. Example 2

[0032] By weight, the raw material components are: 60 parts of hide gelatin (denatured collagen, mainly type I collagen, hydrolyzed peptides, and gelatin), 11 parts of xanthan gum, 11 parts of tara gum, 12 parts of konjac flour, and 6 parts of hydroxypropyl starch. The denaturation degree of the hide gelatin is 8%, the particle size distribution of the konjac flour is 100-600 μm, and the ash content is less than 3%.

[0033] The preparation method is the same as in Example 1. Performance test results: In simulated formation water at 120℃ and with a mineralization of 15×104 mg / L, the complete degradation time is 5 days and the degradation rate reaches 95.8%; after 12 months of storage under room temperature and dry conditions, the premature degradation rate is 1.7%; for artificial fractures with a width of 1.5 mm, the temporary plugging breakthrough pressure reaches 42 MPa and the core permeability recovery value is 91.4%, which shows excellent performance. Example 3

[0034] By weight, the raw material components are: 65 parts of hide gelatin (denatured collagen, mainly type I collagen, hydrolyzed peptides, and gelatin), 12 parts of xanthan gum, 12 parts of tara gum, 10 parts of konjac flour, and 5 parts of hydroxypropyl starch. The denaturation degree of the hide gelatin is 12%, the particle size distribution of the konjac flour is 400-1000 μm, and the ash content is less than 3%.

[0035] The preparation method is the same as in Example 1. Performance test results: In simulated formation water at 50℃ and with a mineralization of 8×104 mg / L, the complete degradation time is 12 days, and the degradation rate reaches 94.9%; after 12 months of storage under room temperature and dry conditions, the premature degradation rate is 0.9%; for artificial fractures with a width of 3 mm, the temporary plugging breakthrough pressure reaches 33 MPa, and the core permeability recovery value is 93.5%, which meets the requirements for low-temperature reservoir construction.

[0036] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biodegradable fracturing diversion plugging agent, characterized in that: By weight, it includes the following raw material components: 55-65 parts of hide glue (denatured collagen matrix, mainly composed of type I collagen, hydrolyzed peptides, and gelatin), 10-12 parts of xanthan gum (microbial polysaccharide degradation regulator), 10-12 parts of tara gum (plant galactomannan binder modifier), 10-13 parts of konjac flour (bio-based enhanced filler particles), and 5-8 parts of hydroxypropyl starch (smoothing agent).

2. The biodegradable fracturing diversion plugging agent as described in claim 1, characterized in that: The skin glue is a denatured animal-derived collagen with a denaturation degree controlled between 8% and 12%. The denaturation process adjusts the cross-linking density and temperature resistance of the collagen.

3. The biodegradable fracturing diversion plugging agent as described in claim 1, characterized in that: The bio-based reinforced filler particles are plant crude fiber components provided by konjac flour, with a particle size distribution of 100-1000μm and an ash content of less than 3%.

4. The biodegradable fracturing diversion plugging agent as described in claim 1, characterized in that: The degradation regulator is xanthan gum prepared by microbial fermentation. The overall degradation rate of the temporary plugging agent is controlled by adjusting the amount of xanthan gum added.

5. The biodegradable fracturing diversion plugging agent as described in claim 1, characterized in that: The adhesive modifier is galactomannan, also known as tarara, extracted from natural plants, used to improve the bonding strength between the matrix and the reinforcing components.

6. The biodegradable fracturing diversion plugging agent as described in claim 1, characterized in that: The lubricant is hydroxypropyl starch, used to improve the smoothness of the injection of temporary plugging agent particles.

7. A method for preparing a biodegradable fracturing deflector plugging agent, as described in any one of claims 1-6, characterized in that: Includes the following steps: (1) Weigh each raw material according to the weight proportions, add the leather glue to deionized water, heat to 55-65℃ to swell and activate, keep warm and stir for 20-30 minutes to obtain the colloidal matrix; (2) Add xanthan gum, tara gum and konjac powder to the colloidal matrix in sequence, keep the temperature and stir for 15-20 minutes at a stirring speed of 300-500 r / min to obtain the mixture; (3) Cool the mixture to 35-45℃, add hydroxypropyl starch, continue stirring for 5-10 minutes, then extrude and granulate, vacuum dry and sieve to obtain HX101 biodegradable fracturing deflector plugging agent.

8. The preparation method of the biodegradable fracturing diversion plugging agent as described in claim 7, characterized in that: The HX101 biodegradable fracturing deflector has a degradation rate of no less than 95%, a reservoir core permeability recovery value of no less than 90%, an applicable reservoir temperature range of 30-150℃, and a controllable degradation cycle of 3-15 days.

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