A knot-type temporary plugging ball for oilfield perforation temporary plugging fracturing

Abstract

The present invention provides a knot-type temporary plugging ball for oilfield perforation temporary plugging and fracturing, which relates to the technical field of oil and gas exploitation engineering. The knot-type temporary plugging ball for oilfield perforation temporary plugging and fracturing includes a fiber rope, a rope body sleeve and a knot body. The fiber rope is disposed through the inside of the rope body sleeve. The knot body is formed by winding around the middle of the rope body sleeve. Bundling bands are provided at both ends of the rope body sleeve. The fiber rope is obtained by pairwise winding and twisting a degradable polyester fiber and a polyethylene fiber into a filament. The knot body should be coated with an organosilicon surfactant on the surface before use. By setting the polyester fiber filaments and the polyethylene fiber filaments to be twisted into a fiber rope, and at the same time, by coating the rope body sleeve and the knot body as a whole with an organosilicon surfactant for surface treatment, the overall temperature resistance and external friction resistance of the knot body can be improved, preventing the external shedding of the temporary plugging ball during the temporary plugging of the oilfield perforation, and improving the overall quality and effect of the temporary plugging use.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation engineering, and specifically to a knot-type temporary plugging ball for wellbore temporary plugging and fracturing in oilfields. Background Art

[0002] Horizontal wells and volume fracturing technologies are important means to increase the single-well production of unconventional reservoirs and achieve economic and efficient development. At present, the main method for horizontal well fracturing is the staged fracturing method of casing cementing and pumping bridge plugs with multi-cluster perforations. However, there are problems such as frequent tripping of tools, uneven in-segment transformation, and high operation costs during fracturing. To solve such problems, generally, increasing the length of the transformation section and combining in-segment temporary plugging and in-fracture temporary plugging methods are used to achieve the purpose of fully transforming the in-segment area and achieving the maximum fracturing transformation volume. Conventional temporary plugging mainly uses granular, powdery, fibrous temporary plugging agents or temporary plugging balls to achieve through different combinations and different dosages.

[0003] Since the addition of granular temporary plugging agents requires precise addition and a certain redundancy, it is necessary to reasonably control the displacement volume, addition amount, and addition speed, which requires extremely high requirements for on-site constructors. Therefore, currently, 95% of the temporary plugging materials used in major domestic oil and gas fields use conventional temporary plugging balls for effective opening of oil well refracturing and multi-cluster perforations in the segment, and are generally used at the wellbore of the oilfield to play the role of wellbore temporary plugging and fracturing. However, the traditional temporary plugging balls have limited temperature resistance, are extremely easy to fall off, and have poor temporary plugging effects. When they form a blockage at the wellbore, they are also difficult to dissolve by themselves, making it difficult to remove. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a knot-type temporary plugging ball for wellbore temporary plugging and fracturing in oilfields, which solves the problems that the traditional temporary plugging balls have limited temperature resistance, are extremely easy to fall off, have poor temporary plugging effects, and when they form a blockage at the wellbore, they cannot dissolve by themselves, making it difficult to remove.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A knot-type temporary plugging ball for wellbore temporary plugging and fracturing in oilfields includes a fiber rope, a rope body sleeve, and a knot body. The fiber rope is disposed through the inside of the rope body sleeve, and the knot body is formed by winding around the middle of the rope body sleeve. Binding bands are provided at both ends of the rope body sleeve.

[0006] Preferably, the rope body sleeve is made of degradable PBS plastic material, and the wall thickness of the rope body sleeve is set to 150 μm. The binding band is made of bio-based degradable polyester rubber material.

[0007] Preferably, the manufacturing process includes the following specific steps:

[0008] S1. Fiber material preparation: Select materials for the preparation process of degradable polyester fiber filaments;

[0009] S2. Fiber parallel winding and twisting forming: The degradable polyester fiber and polyethylene fiber are wound around each other in pairs to form a filament, and then the fiber rope is obtained.

[0010] S3. Sleeve into a rope: Multiple fiber ropes are passed through the rope body sleeve. At this time, the binding tapes at both ends of the rope body sleeve are tightened due to the force, squeezing the multiple fiber ropes to fix the fiber ropes inside the rope body sleeve.

[0011] S4. Knot forming: A knot is wound in the middle of the rope body sleeve to obtain a knot body.

[0012] S5. Material immersion coating: The obtained fiber ropes, rope body sleeves, knot bodies and binding tapes are put into an organosilicon surfactant for surface coating treatment.

[0013] Preferably, the specific steps for preparing the degradable polyester fiber filaments in step S1 include:

[0014] a1. Mix terephthalic acid and propylene glycol, and set concentrated sulfuric acid as a catalyst for the esterification treatment of terephthalic acid and propylene glycol to obtain a crude solution of diol terephthalate.

[0015] a2. In a vacuum environment, the crude solution of diol terephthalate and epoxy resin are controlled at a temperature of 300 °C for polycondensation reaction. After reacting for 2 h, the modified polyester can be obtained.

[0016] a3. Use the modified polyester as a spinning solution for electrospinning treatment in an electrospinning machine, and the degradable polyester fiber filaments can be obtained after cooling.

[0017] Preferably, the double single knot tying method is adopted for the winding formation of the knot in step S4.

[0018] Preferably, the organosilicon surfactant used for immersion coating in step S5 is used to slow down the oil erosion and degradation rate of the fiber rope and the knot body, and its preparation steps include:

[0019] c1. Add allyl polyether and hydrogen-containing silicone oil into the reaction kettle according to the component ratio of 1:1. Under the nitrogen atmosphere and at a temperature of 120 °C, continuously mix and stir for 20 min to obtain an active agent mixed stock solution.

[0020] c2. Add a chloroplatinic acid-isopropanol catalyst accounting for 16% of the stock solution mass into the active agent mixed stock solution, and stir and mix for reaction at a temperature of 200 °C until the whole stock solution is transparent. After cooling, the organosilicon surfactant can be obtained.

[0021] Preferably, the knot temporary plugging ball is applied to the fracturing and production environment of oil and gas wells at a temperature of 30 °C to 204 °C.

[0022] The present invention provides a knot-type temporary plugging ball for oilfield perforation temporary plugging fracturing, with the following beneficial effects:

[0023] In the present invention, by setting the biodegradable polyester fiber filaments and polyethylene fiber filaments to be twisted into a fiber rope, the overall strength and temperature resistance of the rope body inside the casing can be improved. At the same time, by coating the rope body casing and the knot body as a whole with an organosilicon surfactant, the overall friction resistance of the rope body casing and the knot body can be improved. In summary, the overall temperature resistance and external friction resistance of the knot body can be improved, preventing the external shedding of the temporary plugging ball during temporary plugging in the oilfield perforation, and improving the overall quality and effect of temporary plugging use.

[0024] In the present invention, by setting the rope body casing to be made of biodegradable PBS plastic material and the bundling belt to be made of bio-based degradable polyester rubber material, it is convenient for the temporary plugging ball to self-dissolve when it is embedded in the perforation inside for a long time to block, preventing the blockage of the drainage channel. At the same time, by setting the bundling belt on both sides of the rope body casing to limit and fix the fiber rope inside the rope body casing, the connection relationship between the fiber silk thread and the rope body casing is improved. Combining the biodegradable polyester fiber filaments and polyethylene fiber filaments as the materials for twisting and forming the fiber silk thread, the overall compressive capacity of the knot-type temporary plugging ball can be improved, facilitating its use in deep oil wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0026] Figure 2 is a schematic diagram of the preparation process of the present invention;

[0027] Figure 3 is a matching table of the diameters of the rope body casing and the knot body of the present invention;

[0028] Figure 4 is a matching table of the diameter of the knot body and the temporarily plugged oilfield perforation of the present invention.

[0029] Among them, 1, fiber rope; 2, rope body casing; 3, knot body; 4, bundling belt. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Embodiment:

[0032] As Figures 1-4As shown in the figure, an embodiment of the present invention provides a knot - type temporary plugging ball for oil - field perforation temporary plugging and fracturing, which includes a fiber rope 1, a rope body sleeve 2 and a knot body 3. The fiber rope 1 is disposed through the inside of the rope body sleeve 2, and the knot body 3 is formed by winding around the middle part of the rope body sleeve 2. Bundling straps 4 are provided at both ends of the rope body sleeve 2. By setting the bundling straps to limit and fix the fiber rope inside the rope body sleeve on both sides of the rope body sleeve, the connection relationship between the fiber silk and the rope body sleeve is improved.

[0033] The rope body sleeve 2 is made of degradable PBS plastic material, and the wall thickness of the rope body sleeve 2 is set to 150 μm. The bundling strap 4 is made of bio - based degradable polyester rubber material. Therefore, when the temporary plugging ball is conveniently embedded in the perforation inside the well for a long time for plugging, it can achieve self - dissolution, preventing the blockage of the drainage channel.

[0034] The manufacturing process includes the following specific steps:

[0035] S1. Fiber material preparation: Select materials for the preparation of degradable polyester fiber filaments. The raw materials for material preparation also include polyethylene fiber filaments. The degradable polyester fiber filaments and polyethylene fiber filaments are used as materials for fiber twisting and forming, which can improve the overall compressive capacity of the knot - type temporary plugging ball;

[0036] S2. Fiber parallel - line twisting and forming: Twine the degradable polyester fiber and polyethylene fiber around each other in pairs into filaments, that is, obtain the fiber rope 1. By setting the degradable polyester fiber filaments and polyethylene fiber filaments to twist into a fiber rope, the overall strength and temperature resistance inside the rope body sleeve can be improved;

[0037] S3. Sleeve into a rope: Pass multiple fiber ropes 1 through the rope body sleeve 2. At this time, the bundling straps 4 at both ends of the rope body sleeve 2 are tightened due to the force, squeezing the multiple fiber ropes 1 to fix the fiber ropes 1 inside the rope body sleeve 2;

[0038] S4. Knot forming: Wind a knot around the middle part of the rope body sleeve 2 to obtain the knot body 3;

[0039] S5. Material immersion and coating: Put the obtained fiber rope 1, rope body sleeve 2, knot body 3 and bundling strap 4 into an organosilicon surfactant for surface coating treatment. By putting the rope body sleeve and the knot body as a whole into the organosilicon surfactant for surface coating treatment, the overall friction resistance of the rope body sleeve and the knot body can be improved. In summary, the overall temperature resistance and external friction resistance of the knot body can be improved, preventing the external shedding of the temporary plugging ball during temporary plugging in the oil - field perforation and improving the overall quality and effect of temporary plugging use.

[0040] The specific steps for preparing the degradable polyester fiber filaments in step S1 include:

[0041] a1. Mix terephthalic acid and propylene glycol, and set concentrated sulfuric acid as the catalyst for the esterification of terephthalic acid and propylene glycol to obtain a crude solution of diol terephthalate;

[0042] a2. Carry out polycondensation reaction on the crude solution of diol terephthalate and epoxy resin in a vacuum environment at a controlled temperature of 300 °C. After reacting for 2 h, a modified polyester can be obtained;

[0043] a3. Use the modified polyester as a spinning solution for electrospinning treatment in an electrospinning machine, and biodegradable polyester fiber filaments can be obtained after cooling.

[0044] In step S4, the winding of the knot is formed by using a double single knot tying method, which can increase the diameter of the knot, facilitate the temporary plugging ball to be used for temporary plugging in oilfields with larger wellbores, prevent the external shedding of the temporary plugging ball during temporary plugging in oilfield wellbores, and improve the overall quality and effect of temporary plugging use.

[0045] The silicone surfactant used for immersion coating in step S5 is used to slow down the oil erosion and degradation rate of the fiber rope 1 and the knot body 3. Its preparation steps include:

[0046] c1. Add allyl polyether and hydrogen-containing silicone oil into the reaction kettle according to the component ratio of 1:1. Under the nitrogen atmosphere and at a temperature of 120 °C, continuously mix and stir for 20 min to obtain a mixed stock solution of the surfactant;

[0047] c2. Add a chloroplatinic acid-isopropanol catalyst accounting for 16% of the mass of the stock solution into the mixed stock solution of the surfactant, stir and mix for reaction at a temperature of 200 °C until the whole stock solution is transparent, and the silicone surfactant can be obtained after cooling.

[0048] The temporary plugging ball is applied to the fracturing and exploitation environment of oil and gas wells at a temperature of 30 °C to 204 °C.

[0049] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A knot - type temporary plugging ball for oil - field perforation temporary plugging and fracturing, comprising a fiber rope (1), a rope body sleeve (2) and a knot body (3), characterized in that: The fiber ropes (1) are all arranged through the inside of the rope body sleeve (2), the knot body (3) is formed by winding the middle part of the rope body sleeve (2), and bundling belts (4) are arranged at both ends of the rope body sleeve (2); The rope body sleeve (2) is made of degradable PBS plastic material, and the wall thickness of the rope body sleeve (2) is set to 150 μm, and the bundling belt (4) is made of bio-based degradable polyester rubber material; The manufacturing process of the rope knot type temporary plugging ball includes the following specific steps: S1. Fiber material preparation: Select materials for the preparation of degradable polyester fiber filaments; S2. Fiber parallel winding and twisting into filaments: Wind the degradable polyester fiber and polyethylene fiber around each other in pairs to form filaments, that is, the fiber ropes (1) are obtained; S3. Sleeve into a rope: Pass multiple fiber ropes (1) through the rope body sleeve (2). At this time, the bundling belts (4) at both ends of the rope body sleeve (2) are tightened due to the force, squeezing the multiple fiber ropes (1) to fix the fiber ropes (1) inside the rope body sleeve (2); S4. Rope knot forming: Wind a rope knot in the middle of the rope body sleeve (2) to obtain the knot body (3); S5. Material soaking and coating: Put the obtained fiber ropes (1), rope body sleeves (2), knot bodies (3) and bundling belts (4) into an organosilicon surfactant for surface coating treatment; The organosilicon surfactant used for soaking and coating in the S5 step is used to slow down the oil erosion degradation rate of the fiber ropes (1) and the knot bodies (3), and its preparation steps include: c1. Add allyl polyether and hydrogen-containing silicone oil into the reaction kettle according to the proportion of 1:

1. Under the nitrogen atmosphere and at the temperature of 120 °C, continuously mix and stir for 20 min to obtain the surfactant mixed stock solution; c2. Add a chloroplatinic acid-isopropanol catalyst accounting for 16% of the mass of the stock solution into the surfactant mixed stock solution, stir and mix and react at the temperature of 200 °C until the whole stock solution is transparent, and the organosilicon surfactant can be obtained after cooling.

2. The knot - type temporary plugging ball for oil - field perforation temporary plugging and fracturing according to claim 1, characterized in that: The specific steps for the preparation of the degradable polyester fiber filaments in the S1 step include: a1. Mix phthalic acid and propylene glycol, and use concentrated sulfuric acid as a catalyst for the esterification treatment of phthalic acid and propylene glycol to obtain a crude terephthalic acid diol ester solution; a2. Carry out a polycondensation reaction on the crude terephthalic acid diol ester solution and epoxy resin in a vacuum environment, control the temperature at 300 °C, and after reacting for 2 h, the modified polyester can be obtained; a3. Use the modified polyester as a spinning solution for electrospinning treatment in an electrospinning machine, and the degradable polyester fiber filaments can be obtained after cooling.

3. The knot - type temporary plugging ball for oil - field perforation temporary plugging and fracturing according to claim 1, characterized in that: In the S4 step, the winding formation of the rope knot adopts the double single knot tying method.

4. The knot - type temporary plugging ball for oil - field perforation temporary plugging and fracturing according to claim 1, characterized in that: The rope knot temporary plugging ball is applied to the fracturing and exploitation environment of oil and gas wells at a temperature of 30 °C to 204 °C.

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