Energy increasing method for slug type fracturing oil displacement process
By alternately injecting oil displacement agent and water into the wellbore, the problem of poor sand plugging relief effect of isolation fluid in oilfield fracturing was solved, achieving uniform reservoir support and fracture propagation, and improving oil extraction efficiency.
Patent Information
- Application Number
- CN202411004461.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-25
- Publication Date
- 2026-01-27
AI Technical Summary
In existing oilfield fracturing and oil displacement methods, the isolation fluid has a poor effect on alleviating sand plugging, resulting in uneven propagation of proppant in the fractures and affecting the oil extraction effect of the reservoir.
By opening injection holes in the wellbore and alternately injecting oil displacement agent and water, and by adjusting the ratio of oil displacement agent to water in conjunction with reservoir geological information and construction parameters, the alternating injection of oil displacement agent and water can be achieved, thereby alleviating sand blockage and expanding fractures.
It effectively alleviates sand blockage, improves reservoir conductivity, and significantly enhances oil extraction efficiency, with an input-output ratio of over 1:3.5.
Smart Images
Figure CN121407901A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of oilfield fracturing and oil displacement, and in particular to a method for enhancing the capacity of slug fracturing and oil displacement processes. Background Technology
[0002] Because the viscosity ratio of the sand-mixing fluid in current oilfield fracturing and oil displacement methods is generally 1:1, even considering the addition of proppant which increases the viscosity, the propagation within the fractures is still mostly piston-like. Furthermore, once the proppant enters the formation and sand plugging occurs, the spacer fluid struggles to rapidly advance to the leading edge of the proppant and open the fracture using the viscous fingering principle. Even if the spacer fluid can open the fracture to some extent, it does so behind the proppant, having a very limited effect on increasing the fracture width at the proppant front. Therefore, in conventional slug fracturing technology, the spacer fluid's effect on alleviating sand plugging is very small. Therefore, to address these shortcomings, a method for enhancing the performance of slug fracturing and oil displacement is proposed. Summary of the Invention
[0003] (a) Technical problems to be solved This invention provides a method for enhancing the oil displacement process using slug fracturing, overcoming the problem that conventional oilfield fracturing and oil displacement methods often suffer from poor sand plugging mitigation effects due to the isolation fluid.
[0004] (II) Technical Solution To address the above problems, this invention provides a method for enhancing the oil recovery capacity of slug fracturing oil displacement process, comprising: Step S1: Identify the target well, obtain specific data information of the target well, and determine the specific fracturing scheme for the target well based on the specific data information; Step S2: Based on the specific data information determined in Step S1, determine the oil displacement agent mixture and the tools and equipment for normal construction applications; Step S3: Calculate the specific location and number of injection holes inside the wellbore of the target well determined in Step S1, and use the tools and equipment determined in Step S2 to open injection holes inside the wellbore. Step S4: Obtain the geological information of the oil reservoir of the target well based on the specific data information determined in Step S1, determine the type of oil displacement agent based on the geological information of the oil reservoir, and inject the oil displacement agent and water alternately into the target well through the injection hole opened in Step S3 in proportion, and then inject the proppant. Step S5: Based on the effect of injecting oil displacement and clean water in step S4, and in accordance with the on-site construction requirements, adjust the pump injection liquid medium construction parameters; Step S6: Perform fracturing operation on the target well according to the construction parameters obtained in step S5, and obtain the formation internal information of the target well by conducting on-site detection of specific data information inside the wellbore; Step S7: Complete the fracturing operation of the target well, systematically analyze the formation internal information obtained in step S6, and provide a reference for the subsequent construction method of the target well based on the target data obtained from the analysis.
[0005] Preferably, in step S1, the specific data information includes reservoir physical properties, fluid viscosity, target well oil production and water content, past construction data, and production profile.
[0006] Preferably, the physical properties of the oil reservoir include porosity, oil saturation, and permeability.
[0007] Preferably, in step S1, the specific fracturing scheme includes the amount of liquid used, the amount of sand, the displacement rate, and the sand ratio when using pressure-driven fracturing technology.
[0008] Preferably, in step S2, the tools and equipment include a ground-based liquid storage tank, a mixing device, and an oil displacement agent container.
[0009] Preferably, in step S3, the specific location is the target modified layer section, and the quantity includes 16 holes / m, 12 holes / m, or 10 holes / m.
[0010] Preferably, in step S4, the geological information of the oil reservoir is classified as 0-100md, 100-300md, 300-500md, and above 500md; the type of oil displacement agent includes a single-component alkali-free surfactant or a composite oil displacement agent system; the ratio of the oil displacement agent to water is 1-3:1-3.
[0011] Preferably, in step S5, the construction parameters include construction tubing pressure, casing pressure, and discharge rate.
[0012] Preferably, in step S6, the formation internal information includes changes in temperature and pressure within the wellbore and the extension of fractures within the formation.
[0013] Preferably, in step S7, the target data includes the relationship between displacement and pressure, and the relationship between changes in formation temperature and pressure after applying different scales of oil displacement agents to different reservoirs.
[0014] (III) Beneficial Effects The slug fracturing oil displacement process energy enhancement method provided by this invention involves injecting an oil displacement agent and clean water into the wellbore of the target well through an injection port during construction. The process of injecting the oil displacement agent and clean water is alternating. By alternating injection, reservoir energy is replenished, and the phenomenon of sand plugging is alleviated. Furthermore, the ratio of oil displacement agent to clean water can be adjusted according to different reservoir types and physical properties to meet the oil extraction needs of the reservoir. Attached Figure Description
[0015] Figure 1 This is a flowchart of the energy enhancement method for the slug fracturing oil displacement process according to an embodiment of the present invention. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Figure 1 This is a flowchart of the slug fracturing oil displacement process enhancement method according to an embodiment of the present invention, as shown below. Figure 1 As shown, the present invention provides a method for enhancing the capacity of slug-type fracturing oil displacement process, specifically including: Step S1: Identify the target well, obtain specific data information of the target well, and determine the specific fracturing scheme for the target well based on the specific data information; Step S2: Based on the specific data information determined in Step S1, determine the oil displacement agent mixture and the tools and equipment for normal construction applications; Step S3: Calculate the specific location and number of injection holes inside the wellbore of the target well determined in Step S1, and use the tools and equipment determined in Step S2 to open injection holes inside the wellbore. Step S4: Obtain the geological information of the oil reservoir of the target well based on the specific data information determined in Step S1, determine the type of oil displacement agent based on the geological information of the oil reservoir, and inject the oil displacement agent and water alternately into the target well through the injection hole opened in Step S3 in proportion, and then inject the proppant. Step S5: Based on the effect of injecting oil displacement and clean water in step S4, and in accordance with the on-site construction requirements, adjust the pump injection liquid medium construction parameters; Step S6: Perform fracturing operation on the target well according to the construction parameters obtained in step S5, and obtain the formation internal information of the target well by conducting on-site detection of specific data information inside the wellbore; Step S7: Complete the fracturing operation of the target well, systematically analyze the formation internal information obtained in step S6, and provide a reference for the subsequent construction method of the target well based on the target data obtained from the analysis.
[0018] In this method, in step S1, the specific data information includes the physical properties of the oil reservoir, fluid viscosity, oil production and water content of the target well, past construction conditions and production profile. Among them, the physical properties of the oil reservoir include porosity, oil saturation and permeability.
[0019] In practical applications, the specific fracturing scheme in step S1 includes the scale of fluid used, the amount of sand, the displacement rate, and the sand ratio when using pressure-driven fracturing technology.
[0020] In this method, in step S2, the tools and equipment include a ground-based liquid storage tank, a mixing device, and an oil displacement agent container.
[0021] In practical applications, in step S3, the specific location is the target modified layer section, and the quantity includes 16 holes / m, 12 holes / m, or 10 holes / m.
[0022] In this method, in step S4, the geological information of the oil reservoir is classified as 0-100 md, 100-300 md, 300-500 md, and above 500 md; the types of oil displacement agents include single-component alkali-free surfactants or composite oil displacement agent systems, wherein the commonly used ratio of single-component alkali-free surfactants is between 0.1% and 0.5%, and composite oil displacement agent systems include microorganisms, autogenous heat, nano-black cards, etc.; the ratio of oil displacement agent to water is in the range of 1-3:1-3, wherein the ratio of water and oil displacement agent can be freely combined within this range.
[0023] In practical applications, the construction parameters in step S5 include the construction tubing pressure, casing pressure, and discharge rate.
[0024] In this method, in step S6, the formation internal information includes changes in temperature and pressure inside the wellbore, and the extension of fractures within the formation.
[0025] In practical applications, the target data in step S7 includes the relationship between displacement and pressure, and the relationship between changes in formation temperature and pressure after applying different scales of oil displacement agents to different reservoirs.
[0026] This invention provides a method for enhancing the oil recovery capacity of slug fracturing, which can not only alleviate sand plugging but also meet the oil extraction needs of reservoirs. The working principle of this method is described in detail below: Step 1: Identify the target well, obtain specific data information about the target well, and determine the specific fracturing plan for the target well based on the specific data information; Step 2: Based on the specific data, determine the oil displacement agent mixture and the tools and equipment for normal construction applications; Step 3: Calculate the specific location and number of injection holes inside the target wellbore, and use tools and equipment to open injection holes inside the wellbore; Step 4: Obtain the geological information of the oil reservoir of the target well based on the specific data information, determine the type of oil displacement agent based on the geological information of the oil reservoir, and inject the oil displacement agent and water alternately into the target well in proportion through the opened injection hole, and then inject the proppant. Step 5: Based on the effects of injecting oil displacement and clean water, and in accordance with on-site construction requirements, adjust the pump injection liquid medium construction parameters; Step Six: Perform fracturing operations on the target well according to the construction parameters, and obtain the formation internal information of the target well by conducting on-site detection of specific data information inside the wellbore; Step 7: Complete the fracturing operation of the target well, conduct a systematic analysis of the formation internal information, and provide a reference for the subsequent construction methods of the target well based on the target data obtained from the analysis.
[0027] In this embodiment, well N7-10-737 is used as the target well. The highest shut-in pressure of this target well is 11.45 MPa, the target formation temperature is 49.4℃, and the main component of the oil displacement agent is a monobasic alkali-free surfactant with a ratio of 0.5%. The number of injection holes is 16 holes / m. Through the injection holes, the oil displacement agent and water are injected sequentially into the wellbore. The pumping scale is determined based on the pre-pressure production, sand body distribution, and water cut of surrounding connected wells. Then, the proppant dosage can be designed according to the sandstone thickness and porosity, and the proppant injection rate is controlled according to the on-site pressure. Furthermore, when injecting the oil displacement agent and water, the dosage can be determined according to the specific conditions of the wellbore. Different reservoir porosity, permeability, oil saturation, sand body distribution, pre-pressurization production, and formation fluid viscosity are considered. Oil displacement agents and water are injected alternately in different proportions and at different times. The ratio of oil displacement agent to water ranges from 1:1.5 / 1:3 / 2:1 / 3:1. This can improve the permeability of remaining oil in the formation. Simultaneously, the alternating injection method replenishes reservoir energy, removes near-wellbore contamination, further extends fractures, alleviates and prevents sand plugging anomalies, ensures more uniform proppant distribution and better distal support, improves reservoir conductivity, and ultimately leads to better oil extraction results.
[0028] Specifically, in practical applications, based on the effective reservoir thickness, porosity, permeability, oil saturation, sand body characteristics, cumulative fluid production, oil status, connectivity, pre-injection production dynamics, current pressure coefficient, historical construction data, and effect parameters of different oilfield reservoirs, the condition of the oilfield wellbore is first determined to be intact. Well N7-10-737 is taken as the target well. This target well is a tertiary infill well in the South Seventh Block of the X Oilfield. It was put into production in December 2003, with an initial daily fluid production of 3.4t, a daily oil production of 2.74t, and a comprehensive water cut of 19%. Currently, the daily fluid production is 20.2t, the daily oil production is 2.7t, the comprehensive water cut is 86.8%, and the cumulative oil production is 3.36×10⁴t, with a 14.1×10⁴m³ of oil. 3 The current formation pressure coefficient is 0.74. The target well has been fracturing once in the past, with an initial daily oil increase of 14t. However, the increase in fluid volume after perforation was small. There is one water well connected to the well, with an injection pressure of 12.37MPa and a daily actual injection of only 20m³, indicating poor water injection effectiveness. The highest wellhead shut-in pressure is 11.45MPa, the target formation temperature is 49.4℃, the main component of the oil displacement agent is a single-component alkali-free surfactant with a ratio of 0.5%, and the number of injection holes is 16 holes / m.
[0029] In this embodiment, the first layer of the well mainly consists of sheet sandstone with a thickness of 1.9m and an effective thickness of 1.5m. There are no connecting water wells, the permeability is 47mD, the oil saturation is 48.39%, the ratio of oil displacement agent to clear water slug is 2:1, and the production profile test shows good performance. It is 95m from the fault, with a designed sand volume of 43m³ and a fluid volume of 1800m³, and resin sand is used for sand control. The second layer mainly consists of trapped channels with a sandstone thickness of 3.3m and an effective thickness of 2.3m. There are no connecting water wells, the permeability is 372mD, and it is 83m from the fault. The scale should be controlled because this is the first stimulation, the reservoir has not been utilized, and the oil saturation is 52.62%. The ratio of oil displacement agent to clear water slug is 2:1. 1. The design sand volume is 40 m³, and the liquid volume is 2280 m³, with resin sand used for sand control; the third layer mainly consists of sheet sand, with a sandstone thickness of 3.7 m, an effective thickness of 0.9 m, a permeability of 378 mD, and a distance of 38 m from the fault. This layer has two small layers developing longitudinally, and fine-tuning of the small layers is carried out using a multi-fracture method. Due to the high oil saturation, the proportion of oil displacement agent should be increased, with an oil displacement agent to clear water slug ratio of 3:1. The design sand volume is 43 m³, and the liquid volume is 2170 m³, with resin sand used for sand control. Pressure changes are monitored during construction, and construction is stopped if any abnormality is found; the fourth layer mainly consists of sheet sand, with a sandstone thickness of 4.7 m, an effective thickness of 0.9 m, and a distance of 30 m from the fault, with no connecting water wells.
[0030] In practical applications, this layer develops multiple sub-layers longitudinally. The sub-layers are finely modified using a multi-fracture method. The ratio of oil displacement agent to water slug is 1:2. The sand volume is adjusted to 42m³ and the liquid volume to 2990m³. Resin sand is used for sand control. Pressure changes are monitored during construction, and construction is stopped if any abnormality is found.
[0031] In this embodiment, when injecting oil displacement agent and water into the well, the pumping liquid medium construction parameters can be adjusted according to the on-site construction pressure and at any time. By reducing the discharge of the isolation fluid, it is more conducive to the diffusion of the isolation fluid into the fracture system, thereby improving the migration of oil flow near the fracture. After the measures, the well initially increased oil production by 19.8 tons per day, which is more than 4 times higher than the initial oil production of similar wells in the block.
[0032] The slug fracturing oil displacement process enhancement method provided by this invention effectively solves the problem of poor utilization of residual oil after repeated fracturing. Compared with conventional fracturing methods, this method significantly improves the effectiveness of the measures. This method has an excellent effect on the effective utilization of reservoirs with imperfect injection and production, and the input-output ratio can reach more than 1:3.5.
[0033] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.
Claims
1. A method for enhancing the oil recovery capacity of slug fracturing oil displacement process, characterized in that, include: Step S1: Identify the target well, obtain specific data information of the target well, and determine the specific fracturing scheme for the target well based on the specific data information; Step S2: Based on the specific data information determined in Step S1, determine the oil displacement agent mixture and the tools and equipment for normal construction applications; Step S3: Calculate the specific location and number of injection holes inside the wellbore of the target well determined in Step S1, and use the tools and equipment determined in Step S2 to open injection holes inside the wellbore. Step S4: Obtain the geological information of the oil reservoir of the target well based on the specific data information determined in Step S1, determine the type of oil displacement agent based on the geological information of the oil reservoir, and inject the oil displacement agent and water alternately into the target well through the injection hole opened in Step S3 in proportion, and then inject the proppant. Step S5: Based on the effect of injecting oil displacement and clean water in step S4, and in accordance with the on-site construction requirements, adjust the pump injection liquid medium construction parameters; Step S6: Perform fracturing operation on the target well according to the construction parameters obtained in step S5, and obtain the formation internal information of the target well by conducting on-site detection of specific data information inside the wellbore; Step S7: Complete the fracturing operation of the target well, systematically analyze the formation internal information obtained in step S6, and provide a reference for the subsequent construction method of the target well based on the target data obtained from the analysis.
2. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S1, the specific data information includes reservoir physical properties, fluid viscosity, target well oil production and water content, past construction data, and production profile.
3. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 2, characterized in that, The physical properties of the oil reservoir include porosity, oil saturation, and permeability.
4. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S1, the specific fracturing scheme includes the amount of liquid used, the amount of sand, the displacement rate, and the sand ratio when using pressure drive technology.
5. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S2, the tools and equipment include a ground-based liquid storage tank, a mixing device, and an oil displacement agent container.
6. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S3, the specific location is the target modified layer section, and the quantity includes 16 holes / m, 12 holes / m, or 10 holes / m.
7. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S4, the geological information of the oil reservoir is classified as 0-100md, 100-300md, 300-500md, and above 500md; the type of oil displacement agent includes a single-component alkali-free surfactant or a composite oil displacement agent system; the ratio of the oil displacement agent to water is 1-3:1-3.
8. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S5, the construction parameters include the construction tubing pressure, casing pressure, and discharge rate.
9. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S6, the formation internal information includes changes in temperature and pressure within the wellbore and the extension of fractures within the formation.
10. The method for enhancing the oil recovery capacity of slug fracturing oil displacement process according to claim 1, characterized in that, In step S7, the target data includes the relationship between displacement and pressure, and the relationship between changes in formation temperature and pressure after applying different scales of oil displacement agents to different reservoirs.