CN-121993126-A - Injection and production method for residual oil between carbonate reservoirs and application thereof

Abstract

The invention belongs to the technical field of oil and gas field development, and relates to a method for injecting and producing residual oil between carbonate reservoirs and application thereof. The injection and production method comprises the steps of performing injection operation on an original injection well, wherein the injection operation comprises water injection, gas injection and water-gas alternate injection, performing profile control and water shutoff on the original injection well and an original production well after the injection operation is finished, converting at least one original production well into an injection well, converting at least two original injection wells into production wells, and performing injection operation on the injection wells. The number of primary injection wells converted to production wells is positively correlated with the distance between the production well and the injection well. At least one of the original injection wells adjacent to the injection well is converted to a production well. By the method, the method and the device provided by the invention remarkably improve the utilization degree of the residual oil of the carbonate reservoir. Through optimizing the injection and production strategy, reducing fluid channeling and pollution, and improving sweep efficiency, more residual oil is effectively extracted, thereby improving the overall recovery ratio.

Inventors

• Peng Yongcan
• WANG TAO
• ZHANG CHI
• LI JIE
• CHEN FANGFANG
• PENG DEBING
• CAI QUAN
• WANG ZHANGHENG
• WANG NA
• GUO YUE
• YAN TING
• Ai Mingbo

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260508

Application Date

20241105

Claims (10)

1. 1. The method for injecting and producing the residual oil between the carbonate reservoirs is characterized by comprising the following steps of: Performing injection operation on the original injection well (2), wherein the injection operation comprises water injection, gas injection and water-gas alternate injection; After the injection operation is finished, the profile control and water shutoff are carried out on the original injection well (2) and the original oil production well (1); At least one original oil production well (1) is converted into an injection well (5), at least two original injection wells (2) are converted into oil production wells (6), and injection operation is carried out on the injection wells (5).
2. 2. The method of injection and production of residual oil between carbonate reservoirs according to claim 1, characterized in that the number of primary injection wells (2) converted into production wells (6) is positively correlated with the distance between the production wells (6) and injection wells (5).
3. 3. Method for the production of residual oil from carbonate reservoirs between wells according to claim 2, wherein at least one original injection well (2) close to said injection well (5) is converted into a production well (6).
4. 4. The method for injecting and producing residual oil between carbonate reservoirs according to claim 1, wherein the specific conversion relation of converting at least one original oil producing well (1) into an injection well (5) and converting at least two original injection wells (2) into an oil producing well (6) is as follows: Wherein m represents the conversion number of the oil production well (6), n represents the conversion number of the injection well (5), L represents the standard well spacing of the original injection well (2) and the original oil production well (1), and L m represents the well spacing of the oil production well (6) and the injection well (5).
5. 5. The method of injecting and producing residual oil between wells of a carbonate reservoir according to claim 1, wherein the water injection means comprises continuous water injection, intermittent water injection, periodic water injection and pulsed water injection.
6. 6. The method for injecting and producing residual oil between carbonate reservoirs according to claim 1, wherein the gas injection mode comprises continuous gas injection, circulating gas injection and intermittent gas injection.
7. 7. The method for injecting and producing residual oil between carbonate reservoirs according to claim 6, wherein the gas used in the gas injection comprises nitrogen, carbon dioxide gas or a mixed gas of carbon dioxide and nitrogen.
8. 8. The method for injecting and producing residual oil between carbonate reservoirs according to claim 1, wherein the profile control water shutoff gel used in profile control water shutoff is at least one of polyacrylamide gel and nanoparticle gel.
9. 9. The method for injecting and producing residual oil between carbonate reservoirs according to claim 1, wherein the profile control water shutoff foam used in profile control water shutoff is nitrogen foam or carbon dioxide foam.
10. 10. Use of the method for injection and production of residual oil between carbonate reservoirs according to any one of claims 1 to 9 in carbonate reservoirs.

Description

Injection and production method for residual oil between carbonate reservoirs and application thereof Technical Field The invention belongs to the technical field of oil and gas field development, and relates to a method for injecting and producing residual oil between carbonate reservoirs and application thereof. Background The carbonate reservoir mainly comprises cracks, holes and karst cave, the communication condition of the reservoir is complex and various, the difference is extremely large, and the gravity differentiation effect of injected water in the large-scale space in the fracture-cave space is extremely strong. Meanwhile, the carbonate reservoir is extremely strong in heterogeneity and complex in fluid flow characteristics, so that the residual oil of the reservoir is enriched after water driving and gas driving, the displacement use degree is low, the sweep range is small, and the reservoir recovery ratio is low. At present, the method for improving the recovery ratio of the carbonate reservoir has the following steps that in the water injection development process of the carbonate oil field, the reservoir of the weathered crust type carbonate reservoir mainly takes karst cave and holes as main materials, and the gravity differentiation effect in a large-scale space is extremely strong. Conventional water injection plays a role in gravity displacement, but the phenomenon that the injected water is extruded downwards is caused by large density difference between the injected water and crude oil in the longitudinal direction, so that the oil displacement effect between wells is poor. The carbonate reservoir gas injection can effectively solve the problem of attic oil, but also has strong gravity differentiation, and seriously weakens the gas injection and improves the recovery efficiency. Meanwhile, the density difference between gas and crude oil is larger than that between stratum injection water and crude oil, the gas fluidity is larger than that of water, so that gas injection is more serious than that of a water injection dominant channel, the carrying capacity of the gas is poor, and the subsequent gas channeling dominant channel adjustment technology is more severe. The lack of lateral driving force results in the possibility of a great deal of residual oil being enriched between wells of the injection well pattern, and the difficulty in further improving the gas injection development effect of such reservoirs is great. On the basis of failure of water injection and gas injection, gas channeling can be delayed by adopting water-gas alternate injection, so that the swept volume of gas is improved, and the oil reservoir recovery ratio is improved to a certain extent. However, the carbonate reservoir cracks, pores, karst cave and other large-scale reservoir space develop, so that water-gas alternation still easily generates channeling, and the practical application effect is poor. In order to further inhibit the channeling, the carbonate reservoir also adopts a gel and foam profile control and water shutoff technology. However, because the physical properties of the carbonate stratum are complex and the carbonate stratum generally has the characteristics of high temperature and high salt, the profile control water shutoff system has the problems of low strength, poor stability and the like. If the foam is seriously affected by factors such as temperature, mineralization degree and the like, under the formation condition, the surfactant used for foaming is usually decomposed and deactivated at high temperature, and the foam is easier to break and foam when contacting with crude oil, so that the application of the foam is greatly limited. Meanwhile, in the prior art, an operation of replacing a high-water-content oil production well with a water injection well is performed, but the operation is performed according to field experience, and theoretical guidance is not provided, so that the application range is limited. Disclosure of Invention The invention aims to solve the technical problems of water injection gravity replacement failure, serious gas injection and gas channeling and poor water-gas alternating application effect existing in the method for improving the recovery ratio of a carbonate reservoir in the prior art, and provides a method for injecting and extracting residual oil between wells of the carbonate reservoir and application thereof. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: In a first aspect, the invention provides a method for injection and production of remaining oil between carbonate reservoirs, comprising the following steps: performing injection operation on an original injection well, wherein the injection operation comprises water injection, gas injection and water-gas alternate injection; after the injection operation is finished, performing profile control and water shutoff on the original injection