A method for adjusting plugging and driving in horizontal wells without moving the tubing string

Abstract

This application discloses a method for adjusting plugging and displacement in horizontal wells without moving the tubing string, relating to the field of petroleum development technology. This method involves classifying the water absorption index and, at different water absorption indices, selectively adding a water-soluble temporary plugging agent to the tubing or an oil-soluble temporary plugging agent and permeation agent to the casing to gradually reduce the water absorption index, thereby achieving the effects of plugging and displacement adjustment. This method requires no movement of the tubing string, is simple to operate, and is suitable for industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of petroleum development, and specifically relates to a method for adjusting plugging and driving of a horizontal well without moving the tubing string. Background Technology

[0002] Currently, horizontal well development has gradually become one of the development methods for ultra-low permeability oilfields. In order to improve the effect of horizontal wells, some oilfields have begun to explore the development model of injection and production in the same well. However, field tests have found that there are problems such as rapid production decline, rapid water breakthrough, and easy water channeling, which seriously restrict the production of horizontal wells.

[0003] To restore production capacity in high water-cut horizontal wells, two methods are generally used: temporary fracturing or water shut-off. Temporary fracturing in horizontal wells requires the use of a construction tubing string, involves significant modification, and has a long construction period. Water shut-off in horizontal wells is currently mainly used in high water-cut wells, requiring wellbore treatment, tubing string installation and removal, injection of plugging agent, and then resetting. Chinese patent CN111577196A discloses a method for water shut-off in high water-cut horizontal wells in oilfields. This method involves running tubing into the reservoir, installing a solvent release device near the plug on the tubing, and then injecting solvent into the tubing. The solvent reacts with the fluid in the high water-cut section of the formation to form a scale, creating a seal and achieving water shut-off to restore production. This method allows for operation without moving the tubing string, but it can only seal the produced end and cannot adjust the plugging at the injection end. Summary of the Invention

[0004] The main objective of this invention is to provide a method for adjusting plugging and driving in horizontal wells without moving the tubing string, in order to solve the problems in the prior art where the tubing string usually needs to be moved during injection and production in the same well, resulting in a large amount of engineering work or poor plugging effect.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for plugging and adjusting the flow direction of a horizontal well without moving the tubing string is provided. This method allows for simultaneous plugging of the production end and adjusting the flow direction of the injection end without moving the tubing string, thereby reducing the water cut of the horizontal well and increasing crude oil production. The horizontal well includes casing and tubing, with the tubing located inside the casing.

[0006] The methods for adjusting and driving the tubing string in this horizontal well include:

[0007] Calculate the pseudo-water absorption index. Under the first condition, inject water into the casing, then inject oil-soluble temporary plugging agent. After the reaction is complete, calculate the squeezing water absorption index. If the squeezing water absorption index still meets the first condition, repeat the above steps.

[0008] Under the second condition, inject a water-soluble temporary plugging agent into the tubing, control the injection pressure to be 15MPa-23MPa, and then inject an adsorbent into the casing; repeat the above steps if the water absorption index still meets the second condition.

[0009] Under the third condition, a clay stabilizer solution is injected into the casing, and the reaction is completed to achieve plugging and displacement adjustment.

[0010] The proposed water absorption index is the average ratio of the difference between daily water injection and daily fluid production in the first three months of horizontal well operation to the daily oil-water well pressure difference.

[0011] The squeezing water absorption index is the ratio of the instantaneous volume of water injected during horizontal well construction to the squeezing pressure.

[0012] The first condition is that the apparent water absorption index is greater than 3m. 3 / (d·MPa);

[0013] The second condition is that the liquid absorption index is less than or equal to 3m. 3 / (d·MPa), greater than 2m 3 / (d·MPa);

[0014] The third condition is that the liquid absorption index is less than or equal to 2m. 3 / (d·MPa).

[0015] Furthermore, the water-soluble temporary plugging agent is a water-soluble microemulsion type temporary plugging agent;

[0016] By mass fraction, the water-soluble temporary plugging agent comprises: 10%-20% of a first surfactant, 10%-15% of a first oil-soluble plugging material, and 5%-8% of a first corrosion inhibitor; and / or

[0017] By mass fraction, the oil-soluble temporary plugging agent comprises: 4%-7% of a second oil-soluble plugging material, 15%-20% of nanofibers, 3%-5% of a first pH adjuster, and 15%-20% of a second corrosion inhibitor; and / or

[0018] By mass fraction, the percolating agent comprises: 23%-28% of a second surfactant, 3%-5% of a second pH adjuster, and 8%-10% of a polymer.

[0019] Further, the first surfactant includes at least one of alkylphenol polyoxyethylene ether, C12-18 fatty alcohol polyoxyethylene ether, and sorbitan ester; and / or

[0020] The first oil-soluble sealing material includes at least one of bone glue, gum arabic, and natural rubber; and / or

[0021] The first corrosion inhibitor includes at least one of benzoic acid and sorbic acid; and / or

[0022] The second oil-soluble sealing material includes at least one of asphalt, resin; and / or

[0023] The first pH adjuster is at least one of sodium hydroxide, potassium carbonate, and sodium carbonate; and / or

[0024] The second corrosion inhibitor includes at least one of hexadecylpyridine bromide, tallow amine, and octadecylamine; and / or

[0025] The second surfactant includes at least one of sodium dodecylbenzenesulfonate, nano-iron oxide (Fe3O4), and nano-silica; and / or

[0026] The second pH adjuster is at least one of sodium hydroxide, sodium carbonate, and potassium carbonate; and / or

[0027] The polymer includes at least one of polyacrylamide and polyethylene glycol; and / or

[0028] The clay stabilizer solution is an aqueous solution with a clay stabilizer mass fraction of 5%-8%, and the clay stabilizer contains at least one of potassium chloride and ammonium chloride.

[0029] Furthermore, the first surfactant is alkylphenol polyoxyethylene ether, the first oil-soluble sealing material is bone glue, and the first corrosion inhibitor is benzoic acid; and / or

[0030] The second oil-soluble sealing material is asphalt, specifically rock asphalt; the second corrosion inhibitor is hexadecylpyridine bromide; and / or

[0031] The second surfactant is a compound of sodium dodecylbenzenesulfonate and nano-ferric oxide; and / or

[0032] The polymer is polyacrylamide.

[0033] Furthermore, in the second surfactant, the mass ratio of sodium dodecylbenzenesulfonate to nano-ferric oxide is (8-10):(15-18).

[0034] Furthermore, the preparation method of the water-soluble temporary plugging agent is as follows: melt the first oil-soluble plugging material, then add the first surfactant and the first corrosion inhibitor to it, and then add water or a mixture of water and the backflow liquid to obtain the water-soluble temporary plugging agent.

[0035] Furthermore, the preparation method of the oil-soluble temporary plugging agent is as follows: melt the second oil-soluble plugging material, then add nanofibers, a second corrosion inhibitor and a first pH adjuster to it, stir, then cool to obtain solid particles, and finally mix with a solvent to obtain the oil-soluble temporary plugging agent.

[0036] Furthermore, the stirring conditions are 3000 r / min-4000 r / min; the solvent includes at least one of white oil and kerosene.

[0037] Furthermore, for an oil reservoir with a porosity of 5%-8% and a thickness of 4m-12m, under the first condition, the mass of water injected into the casing each time is 15m.3 -20m 3 Under the first condition, the mass of oil-soluble temporary plugging agent injected into the casing each time is 1t-2t, and the reaction time is 12h-24h; under the second condition, the mass of water-soluble temporary plugging agent injected into the tubing each time is 1t-2t, and the mass of permeation agent injected into the casing each time is 2t-3t; under the third condition, the reaction time is 12h-24h.

[0038] Furthermore, the initial water cut of the horizontal well is above 60%; the initial water cut is the average water cut of the produced product one month prior.

[0039] By applying the technical solution of this invention, water-soluble temporary plugging agents, oil-soluble temporary plugging agents, or permeation agents are injected into the casing or tubing in stages according to the water absorption index. This can simultaneously achieve plugging and displacement adjustment of horizontal wells, which helps to improve the production and quality of crude oil. Moreover, the amount of temporary plugging agents and permeation agents required is relatively small, the cost is low, and the operation is simple. Detailed Implementation

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0041] Simultaneous injection and production in a single well refers to an oilfield development method that involves both water injection and oil production operations within a single well. This method is primarily used in oilfields where well productivity is declining rapidly or where the well has entered the later stages of development. By injecting water into the oil-bearing formation, the internal pressure of the formation is increased, promoting oil flow and improving production efficiency. Simultaneously, oil production operations allow the well to extract oil, effectively utilizing the oilfield's reserves. However, in practice, it has been found that the simultaneous injection and production model suffers from problems such as rapid production decline, rapid water breakthrough, and susceptibility to water channeling. Existing solutions often fail to achieve simultaneous water shut-off and flow regulation, thus hindering the realization of the original advantages of simultaneous injection and production in a single well.

[0042] To solve the above-mentioned technical problems, this application provides a method for adjusting plugging and driving in a horizontal well without moving the tubing string. The horizontal well contains casing and tubing, with the tubing located inside the casing.

[0043] The methods for adjusting and driving the tubing string in this horizontal well include:

[0044] Calculate the pseudo-water absorption index. Under the first condition, inject water into the casing, then inject oil-soluble temporary plugging agent. After the reaction is complete, calculate the squeezing water absorption index. If the squeezing water absorption index still meets the first condition, repeat the above steps.

[0045] Under the second condition, inject a water-soluble temporary plugging agent into the tubing, control the injection pressure to be 15MPa-23MPa, and then inject an adsorbent into the casing; repeat the above steps if the water absorption index still meets the second condition.

[0046] Under the third condition, a clay stabilizer solution is injected into the casing to react and complete the plugging and displacement adjustment; this reaction proceeds faster and more completely after the well is shut in.

[0047] The proposed water absorption index is the average ratio of the difference between daily water injection and daily fluid production in the first three months of horizontal well operation to the daily oil-water well pressure difference.

[0048] The squeezing water absorption index is the ratio of the instantaneous volume of water injected during horizontal well construction to the squeezing pressure.

[0049] Both the pseudo-water absorption index and the squeeze water absorption index characterize the performance characteristics of the formation; the instantaneous liquid volume and squeezing pressure can be directly read from the monitoring instruments on the squeezing truck by squeezing water.

[0050] The first condition is that the apparent water absorption index is greater than 3m. 3 / (d·MPa);

[0051] The second condition is that the liquid absorption index is less than or equal to 3m. 3 / (d·MPa), greater than 2m 3 / (d·MPa);

[0052] The third condition is that the liquid absorption index is less than or equal to 2m. 3 / (d·MPa).

[0053] The effectiveness of plugging a horizontal well can be judged based on the water absorption index. When the water absorption index is high, adding an oil-soluble temporary plugging agent directly to the casing can quickly plug water and reduce the water cut of the horizontal well. However, increasing the amount of oil-soluble temporary plugging agent to reduce the water cut to the target value can easily cause blockage. This application, by adding oil-soluble temporary plugging agent, water-soluble temporary plugging agent and permeation agent in stages, can control the water absorption capacity of the formation in both the injection and production ends. While adjusting the plugging and reducing the water cut, it can improve the fluidity of the formation oil, increase production and improve the quality of the oil.

[0054] In a preferred embodiment of the present invention, the water-soluble temporary plugging agent is a water-soluble microemulsion type temporary plugging agent;

[0055] By mass fraction, the water-soluble temporary plugging agent comprises: 10%-20% of a first surfactant, 10%-15% of a first oil-soluble plugging material, and 5%-8% of a first corrosion inhibitor; and / or

[0056] By mass fraction, the oil-soluble temporary plugging agent comprises: 4%-7% of a second oil-soluble plugging material, 15%-20% of nanofibers, 3%-5% of a first pH adjuster, and 15%-20% of a second corrosion inhibitor; and / or

[0057] By mass fraction, the percolating agent comprises: 23%-28% of a second surfactant, 3%-5% of a second pH adjuster, and 8%-10% of a polymer.

[0058] Grafting surfactants onto the surface of oil-soluble plugging materials can yield water-soluble microemulsion-type temporary plugging agents that do not dissolve in the oil. When added to the oil pipeline, these agents can bridge and block the flow channels of the produced water.

[0059] Adding corrosion inhibitors to water-soluble and oil-soluble temporary plugging agents can slow down the corrosion process of tubing and casing, thus extending the service life of equipment. Using a combination of oil-soluble plugging materials and nanofibers in oil-soluble temporary plugging agents can improve their plugging effect. Adding pH adjusters to regulate the reaction environment further enhances the plugging effect of both the oil-soluble temporary plugging materials and nanofibers.

[0060] By controlling the amounts of surfactants, secondary pH adjusters, and polymers in the permeabilizer to meet the above conditions, the wettability of water on the tubing in the horizontal well can be improved, facilitating its introduction into the formation and increasing well pressure, thereby enhancing oil flowability and production. By limiting the timing and composition of the addition of oil-soluble temporary plugging agents, water-soluble temporary plugging agents, and permeabilizers as described above, both the oil production and oil quality of the horizontal well have been improved.

[0061] In a preferred embodiment of the present invention, the first surfactant includes at least one of alkylphenol polyoxyethylene ether, C12-18 fatty alcohol polyoxyethylene ether, and sorbitan ester; and / or

[0062] The first oil-soluble sealing material includes at least one of bone glue, gum arabic, and natural rubber; and / or

[0063] The first corrosion inhibitor includes at least one of benzoic acid and sorbic acid; and / or

[0064] The second oil-soluble sealing material includes at least one of asphalt, resin; and / or

[0065] Nanofibers include at least one of silica nanofibers and alumina nanofibers; and / or

[0066] The first pH adjuster includes at least one of sodium hydroxide, potassium carbonate, and sodium carbonate; and / or

[0067] The second corrosion inhibitor includes at least one of hexadecylpyridine bromide, tallow amine, and octadecylamine; and / or

[0068] The second surfactant includes at least one of sodium dodecylbenzenesulfonate, nano-ferric oxide, and nano-silica; and / or

[0069] The second pH adjuster includes at least one of sodium hydroxide, potassium carbonate, and sodium carbonate; and / or

[0070] The polymer includes at least one of polyacrylamide and polyethylene glycol; and / or

[0071] The clay stabilizer solution is an aqueous solution with a clay stabilizer mass fraction of 5%-8%, and the clay stabilizer contains at least one of potassium chloride and ammonium chloride.

[0072] In a preferred embodiment of the present invention, the first surfactant is alkylphenol polyoxyethylene ether, the first oil-soluble sealing material is bone glue, and the first corrosion inhibitor is benzoic acid; and / or

[0073] The second oil-soluble sealing material is asphalt, specifically rock asphalt; the second corrosion inhibitor is hexadecylpyridine bromide; and / or

[0074] The second surfactant is a compound of sodium dodecylbenzenesulfonate and nano-ferric oxide; and / or

[0075] The polymer is polyacrylamide.

[0076] Because of the interaction between different components, when the types of each component meet the above-mentioned limitations, the required performance of each component can be better exerted, thereby improving the plugging effect, reducing water cut, and increasing oil recovery rate.

[0077] In a preferred embodiment of the present invention, the mass ratio of sodium dodecylbenzenesulfonate to nano-ferric oxide in the second surfactant is (8-10):(15-18). Using sodium dodecylbenzenesulfonate and nano-ferric oxide as surfactants, the water absorption index after the extrusion liquid can reach 1m. 3 / (d·MPa) or higher, 2m 3 Below / (d·MPa), the two can work together to improve the wettability of water on the pipe surface, reduce the water-oil interfacial tension, reduce the oil production start-up pressure, and at the same time play a good role in water plugging, thereby improving the oil production and quality.

[0078] In a preferred embodiment of the present invention, the water-soluble temporary plugging agent is prepared by melting a first oil-soluble plugging material, then adding a first surfactant and a first corrosion inhibitor, followed by water or a mixture of water and flowback fluid to obtain the water-soluble temporary plugging agent. The oil-soluble temporary plugging agent is prepared by melting a second oil-soluble plugging material, then adding nanofibers, a second corrosion inhibitor, and a first pH adjuster, stirring, cooling, forming solid particles, and finally mixing with a solvent to obtain the oil-soluble temporary plugging agent. Using the above methods, a temporary plugging agent material with uniform composition can be prepared, fully utilizing the effects of each component in the temporary plugging agent, achieving both plugging and flow regulation with relatively small dosages.

[0079] In a preferred embodiment of the present invention, when preparing the oil-soluble temporary plugging agent, the stirring conditions are 3000 r / min-4000 r / min, and the solvent includes at least one of white oil and kerosene. The temporary plugging agent prepared under these conditions has a more uniform composition.

[0080] In a preferred embodiment of the present invention, for an oil reservoir with a porosity of 5%-8% and a reservoir thickness of 4m-12m, under the first condition, the mass of water injected into the casing each time is 15m³. 3 -20m 3 Under the following conditions, the mass of oil-soluble temporary plugging agent injected into the casing each time is 1-2 t, and the reaction time is 12-24 h; under the second condition, the mass of water-soluble temporary plugging agent injected into the tubing each time is 1-2 t, and the mass of percolator injected into the casing each time is 2-3 t; under the third condition, the reaction time is 12-24 h. The above-mentioned limits on the amount added each time are to balance the water plugging and displacement performance. After treatment with the above-mentioned amounts of water-soluble temporary plugging agent, oil-soluble temporary plugging agent, and percolator, the squeezing fluid absorption index can reach 0.8 m. 3 / (d·MPa)-2m 3 / (d·MPa) will not drop too low suddenly, has good regulation and driving performance, and will not be difficult to reduce or require a large amount of raw materials to reduce, so that the water content in the produced is low.

[0081] In a preferred embodiment of the present invention, the initial water cut of the horizontal well is 60% or higher; the initial water cut is the average water cut of the produced product one month prior. When the initial water cut is below 60%, the horizontal well does not require plugging treatment; when the initial water cut is above this value, the graded plugging and displacement method described in this invention can significantly improve the oil quality of the horizontal well.

[0082] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0083] The following examples and comparative examples were all carried out in an oil reservoir with a formation porosity of 6% and a reservoir thickness of 8m, with a casing inner diameter of 124mm and a tubing inner diameter of 62mm.

[0084] Example 1

[0085] An embodiment of the horizontal well plugging and displacement adjustment method with the tubing remaining stationary according to the present invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well. The plugging and displacement adjustment method includes the following steps:

[0086] S1, calculated to have a water absorption index of 8m 3 / (d·MPa), 20t of water and 1.5t of oil-soluble temporary plugging agent are injected into the casing, and the reaction is carried out for 12 hours. The squeeze-out water absorption index is calculated to be 3m. 3 / (d·MPa);

[0087] S2, inject 2t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 20.5MPa, then inject 3t of permeabilizing agent into the casing. At this point, the water absorption index reaches 2.6m. 3 / (d·MPa); then inject 1.5t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 22MPa, and then inject 2t of permeation agent into the casing. At this point, the water absorption index reaches 1.8m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent;

[0088] S3, add 5t of clay stabilizer aqueous solution with a clay stabilizer mass fraction of 8% to the casing, shut in the well for 24h to achieve plugging and drive adjustment.

[0089] The simulated water absorption index is the ratio of the difference between the historical daily injection volume and the production volume of a horizontal well to the pressure difference.

[0090] The squeezing fluid absorption index is the ratio of the instantaneous fluid volume injected to the injection pressure during horizontal well construction.

[0091] Potassium chloride is selected as the clay stabilizer.

[0092] The water-soluble temporary plugging agent is composed of alkylphenol polyoxyethylene ether, bone glue, benzoic acid, and water. By mass fraction, its composition is: 20% alkylphenol polyoxyethylene ether, 15% bone glue, 8% benzoic acid, and the balance being water. The bone glue is heated to above 60°C, then benzoic acid and alkylphenol polyoxyethylene ether are added separately, followed by the backflow solution and water, and then mixed thoroughly.

[0093] The oil-soluble temporary plugging agent is composed of rock asphalt, silica nanofibers, sodium hydroxide, hexadecyl pyridine bromide, and white oil. By mass fraction, its composition is: rock asphalt 7%, nanofibers 20%, sodium hydroxide 5%, hexadecyl pyridine bromide 20%, and the balance being white oil. The rock asphalt is heated to 110°C, then the nanofibers and hexadecyl pyridine bromide are added. Sodium hydroxide is added while stirring at a rate of 3500 rpm. The mixture is cooled and shaped into nanoparticles, which are then finally mixed with white oil.

[0094] The permeabilizer is a mixture of sodium dodecylbenzenesulfonate, nano Fe3O4, sodium hydroxide and polyacrylamide; by mass fraction, its composition is: 10% sodium dodecylbenzenesulfonate, 18% nano Fe3O4, 5% sodium hydroxide, 10% polyacrylamide, and the balance is water.

[0095] Example 2

[0096] One embodiment of the horizontal well pipelining and displacement method described in this invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). The difference between its plugging and displacement methods and those in Example 1 is that the mass fraction of sodium dodecylbenzenesulfonate in the absorbent is 8.7%, and the mass fraction of nano-Fe3O4 is 19.3%; in S2, 2t of water-soluble temporary plugging agent is injected into the tubing, the injection pressure reaches 20.6MPa, and then 3t of absorbent agent is injected into the casing, at which point the water absorption index reaches 2.6m. 3 / (d·MPa); then inject 2t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 22.1MPa, and then inject 2t of permeation agent into the casing. At this point, the water absorption index reaches 1.5m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent.

[0097] Example 3

[0098] One embodiment of the horizontal well pipelining and displacement method described in this invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). The difference between its plugging and displacement methods and those in Example 1 is that the mass fraction of sodium dodecylbenzenesulfonate in the percolator is 11.2%, and the mass fraction of nano-Fe3O4 is 16.8%; in S2, 2t of water-soluble temporary plugging agent is injected into the tubing, the injection pressure reaches 20.1MPa, and then 2.5t of percolator is injected into the casing, at which point the squeezing water absorption index reaches 2.5m. 3 / (d·MPa); then inject 1.5t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 21.9MPa, and then inject 2t of permeation agent into the casing, at which point the squeezing water absorption index reaches 2m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent.

[0099] Example 4

[0100] One embodiment of the horizontal well pipelining and displacement method described in this invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). The difference between its plugging and displacement methods and those in Example 1 is that the mass fraction of sodium dodecylbenzenesulfonate in the percolator is 7%, and the mass fraction of nano-Fe3O4 is 21%; in S2, 2t of water-soluble temporary plugging agent is injected into the tubing, the injection pressure reaches 20.6MPa, and then 3t of percolator is injected into the casing, at which point the squeezing water absorption index reaches 2.8m. 3 / (d·MPa); then inject 2t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 23.5MPa, and then inject 2t of permeation agent into the casing. At this point, the water absorption index reaches 2.2m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent.

[0101] Example 5

[0102] One embodiment of the horizontal well pipelining and displacement method described in this invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). The difference between its plugging and displacement methods and those in Example 1 is that the mass fraction of sodium dodecylbenzenesulfonate and the mass fraction of nano-Fe3O4 in the percolator are 14%; in S2, 2t of water-soluble temporary plugging agent is injected into the tubing, the injection pressure reaches 20.5MPa, and then 3t of percolator is injected into the casing, at which point the water absorption index reaches 2.7m. 3 / (d·MPa); then inject 2t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 21.1MPa, and then inject 2t of percolating agent into the casing, at which point the squeezing water absorption index reaches 2.3m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent.

[0103] Example 6

[0104] One embodiment of the horizontal well pipelining and displacement method described in this invention uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). The difference between its plugging and displacement methods and those in Example 1 is that the mass fraction of nano-Fe3O4 in the percolator is 28%; in S2, 2t of water-soluble temporary plugging agent is injected into the tubing, the injection pressure reaches 20.5MPa, and then 3t of percolator is injected into the casing, at which point the squeezing water absorption index reaches 2.9m. 3 / (d·MPa); then inject 2t of water-soluble temporary plugging agent into the tubing, reaching an injection pressure of 24.7MPa, and then inject 2t of permeation agent into the casing, at which point the water absorption index reaches 2.5m. 3 / (d·MPa), stop injecting water-soluble temporary plugging agent and percolating agent.

[0105] Comparative Example 1

[0106] A method for adjusting plugging and driving in horizontal wells without moving the tubing string. This method uses a horizontal injection-production well with an initial water cut of 70% that has been in production for one month as the target well, with a proposed water absorption index of 8m. 3 / (d·MPa). This method does not inject water-soluble temporary plugging agent, oil-soluble temporary plugging agent, and percolator into the casing and tubing in stages. It only reduces the water absorption index by injecting oil-soluble temporary plugging agent and percolator into the casing. The difference from Example 2 is that 4t of oil-soluble temporary plugging agent is injected into the casing at an injection pressure of 24.2MPa, and then 5t of percolator is injected into the casing. At this point, the water absorption index reaches 2.6m. 3 / (d·MPa).

[0107] The test results above show that, in Comparative Example 1, with the same amount of temporary plugging agent and percolator as Example 2, the rate of decrease in the squeezing water absorption index was significantly lower than that of the present invention, indicating a relatively higher cost for plugging and displacement adjustment. Furthermore, when the percolator contains both sodium dodecylbenzenesulfonate and nano-Fe3O4 as surfactants, its plugging and displacement adjustment effects are significantly better than when only one surfactant is used, resulting in a faster decrease in the squeezing water absorption index. Additionally, when the mass ratio of sodium dodecylbenzenesulfonate to nano-Fe3O4 is (8-10):(15-18), after S2, the squeezing water absorption index consistently falls below 2m. 3 Below / (d·MPa), it has both excellent blockage and drive regulation effects.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for adjusting plugging and driving in a horizontal well with a stationary tubing string, characterized in that, The horizontal well includes a casing and tubing, with the tubing located inside the casing. The methods for adjusting blockage and drive include: Calculate the pseudo-water absorption index. Under the first condition, water is injected into the casing, followed by an oil-soluble temporary plugging agent. After the reaction is complete, the squeeze water absorption index is calculated. If the squeeze water absorption index still meets the first condition, the above steps are repeated. Under the second condition, a water-soluble temporary plugging agent is injected into the tubing, and the injection pressure is controlled at 15MPa-23MPa. Then, an adsorption agent is injected into the casing. If the water absorption index still meets the second condition, the above steps are repeated. Under the third condition, a clay stabilizer solution is injected into the casing, and a reaction is carried out to complete the plugging and driving adjustment. The proposed water absorption index is the average ratio of the difference between daily water injection and daily fluid production in the horizontal well over the first three months to the daily oil-water well pressure difference. The squeezing water absorption index is the ratio of the instantaneous volume of water injected during horizontal well construction to the injection pressure. The first condition is that the pseudo-water absorption index is greater than 3m. 3 / (d·MPa); The second condition is that the liquid absorption index is less than or equal to 3m. 3 / (d·MPa), greater than 2m 3 / (d·MPa); The third condition is that the liquid absorption index is less than or equal to 2m. 3 / (d·MPa).

2. The method for adjusting blockage and drive according to claim 1, characterized in that, The water-soluble temporary plugging agent is a water-soluble microemulsion type temporary plugging agent. Based on mass fraction, the water-soluble temporary plugging agent comprises: 10%-20% of a first surfactant, 10%-15% of a first oil-soluble plugging material, and 5%-8% of a first corrosion inhibitor; and / or According to mass fraction, the oil-soluble temporary plugging agent comprises: 4%-7% of a second oil-soluble plugging material, 15%-20% of nanofibers, 3%-5% of a first pH adjuster, and 15%-20% of a second corrosion inhibitor; and / or The permeating agent comprises, by mass fraction: 23%-28% of a second surfactant, 3%-5% of a second pH adjuster, and 8%-10% of a polymer.

3. The method for adjusting blockage and drive according to claim 2, characterized in that, The first surfactant comprises at least one of alkylphenol polyoxyethylene ether, C12-18 fatty alcohol polyoxyethylene ether, and sorbitan ester; and / or The first oil-soluble sealing material includes at least one of bone glue, gum arabic, and natural rubber; and / or The first corrosion inhibitor includes at least one of benzoic acid and sorbic acid; and / or The second oil-soluble sealing material includes at least one of asphaltene and resin; and / or The first pH adjuster includes at least one of sodium hydroxide, potassium carbonate, and sodium carbonate; and / or The second corrosion inhibitor includes at least one of hexadecylpyridine bromide, tallow amine, and octadecylamine; and / or The second surfactant includes at least one of sodium dodecylbenzenesulfonate, nano-ferric oxide, and nano-silica; and / or The second pH adjuster includes at least one of sodium hydroxide, potassium carbonate, and sodium carbonate; and / or The polymer includes at least one of polyacrylamide and polyethylene glycol; and / or The clay stabilizer solution is an aqueous solution with a clay stabilizer mass fraction of 5%-8%, and the clay stabilizer contains at least one of potassium chloride and ammonium chloride.

4. The method for adjusting blockage and drive according to claim 3, characterized in that, The first surfactant is alkylphenol polyoxyethylene ether, the first oil-soluble sealing material is bone glue, and the first corrosion inhibitor is benzoic acid; and / or The second oil-soluble sealing material is asphalt, wherein the asphalt is rock asphalt, and the second corrosion inhibitor is hexadecylpyridine bromide; and / or The second surfactant is a compound of sodium dodecylbenzenesulfonate and nano-ferric oxide; and / or The polymer is polyacrylamide.

5. The method for adjusting blockage and drive according to claim 4, characterized in that, In the second surfactant, the mass ratio of sodium dodecylbenzenesulfonate to nano-ferric oxide is (8-10):(15-18).

6. The method for adjusting the blockage and drive according to any one of claims 2 to 5, characterized in that, The water-soluble temporary plugging agent is prepared by melting the first oil-soluble plugging material, then adding the first surfactant and the first corrosion inhibitor to it, and then adding water or a mixture of water and the backflow solution to obtain the water-soluble temporary plugging agent.

7. The method for adjusting the blockage and drive according to any one of claims 2 to 5, characterized in that, The preparation method of the oil-soluble temporary plugging agent is as follows: the second oil-soluble plugging material is melted, and then the nanofiber, the second corrosion inhibitor and the first pH adjuster are added to it, stirred, cooled, and solid particles are obtained. Finally, it is mixed with a solvent to obtain the oil-soluble temporary plugging agent.

8. The method for adjusting blockage and drive according to claim 7, characterized in that, The stirring conditions are 3000 r / min-4000 r / min; the solvent includes at least one of white oil and kerosene.

9. The method for adjusting the blockage and drive according to any one of claims 1 to 5, characterized in that, For an oil reservoir with a formation porosity of 5%-8% and a thickness of 4m-12m, under the first condition, the mass of water injected into the casing each time is 15m³. 3 -20m 3 In the first case, the mass of the oil-soluble temporary plugging agent injected into the casing each time is 1t-2t, and the reaction time is 12h-24h; in the second case, the mass of the water-soluble temporary plugging agent injected into the tubing each time is 1t-2t, and the mass of the permeation agent injected into the casing each time is 2t-3t; in the third case, the reaction time is 12h-24h.

10. The method for adjusting the blockage and drive according to any one of claims 1 to 5, characterized in that, The initial water cut of the horizontal well is above 60%; the initial water cut is the average water cut of the produced product one month prior.