A method and system for comprehensive post-fracturing evaluation of ultra-deep fractured reservoirs

Abstract

The application discloses a kind of super deep fractured reservoir post-fracturing comprehensive determination method and system, the method includes: according to the data in fracturing construction process, the development degree and effectiveness of reservoir natural fracture are analyzed and judged;According to the pressure difference of instantaneous bottom hole shut-in pressure and formation pressure after pump stop and the pressure drop of surface shut-in pressure in first predetermined time, the development degree and effectiveness of natural fracture are analyzed and judged;According to the pressure and time data in post-fracturing well test testing process, the development degree and effectiveness of natural fracture are analyzed and judged;According to the data of fracturing construction process, the pressure difference of instantaneous bottom hole shut-in pressure and formation pressure after pump stop, the pressure drop of surface shut-in pressure in predetermined time and the pressure and time data in post-fracturing well test testing process, four aspects of comprehensive analysis are carried out, and finally the development degree and effectiveness of natural fracture are judged.Solve the problem that super deep fractured reservoir is influenced by high temperature and high pressure, and the development degree and effectiveness evaluation determination method is insufficient.

Description

Technical Field

[0001] This invention relates to the field of reservoir stimulation technology in oil and gas field development, and in particular to a comprehensive post-fracturing assessment method and system for ultra-deep fractured reservoirs. Background Technology

[0002] In recent years, deep oil and gas has become an important area of ​​oil and gas exploration and development in my country. The reservoirs in this region are characterized by deep burial (6000-8500m), extremely thick target layers (100-300m), high temperature, high pressure, high stress, low porosity and permeability of the matrix, well-developed natural fractures, and strong heterogeneity. Fracturing and acidizing are important measures for increasing production in deep oil and gas reservoirs. However, due to the high temperature and pressure of deep reservoirs, the deployment of auxiliary equipment into the well is difficult. Even with the development and application of post-fracturing assessment technology, there is still no method that can both economically and accurately assess the post-fracturing situation.

[0003] Currently, post-fracturing assessment methods can be broadly categorized into three types: (1) Indirect monitoring methods: These mainly include net pressure analysis, unstable well testing (pressure unstable well testing PTA, production unstable well testing RTA), production analysis history fitting, etc. The main drawback of this method is that the analysis results are often non-singular and need to be corrected using direct fracture monitoring results. (2) Direct monitoring near the wellbore: This includes radioactive tracers, temperature logging, production logging, and wellbore measurement, etc. The main drawback of this method is that it can only obtain fracture parameters within 1m of the wellbore. The production profile obtained by tracer monitoring cannot be refined to the cluster level, and it cannot accurately determine the production volume of each stage. It also cannot monitor gas flow. (3) Direct far-field monitoring: This includes microseismic technology, surface inclinometers, downhole inclinometers, and fiber optic monitoring, etc. Far-field monitoring technology monitors from the well or the surface and can obtain the expansion of fractures in the far field. Microseismic fracturing monitoring is limited by the monitoring distance (not exceeding 1200m), and microseismic information has multiple solutions. The height and length of the fracture monitored by microseismic monitoring also differ from the actual size of the supporting fracture. Due to the influence of high temperature and high pressure, direct far-field monitoring methods have low accuracy and high cost.

[0004] In conventional reservoirs and tight sandstone, hydraulic fracturing produces symmetrical biplane fractures. Fracture half-length and conductivity are the main parameters for evaluating the post-fracturing effect of this type of reservoir. In ultra-deep fractured reservoirs, hydraulic fracturing produces complex fracture networks. Single fracture half-length and conductivity are insufficient to describe the fracturing effect. The development and effectiveness of natural fractures in ultra-deep formations are directly proportional to the post-fracturing effect. A renewed understanding of the reservoir helps optimize the stimulation design of adjacent wells, further improving the effectiveness and economy of ultra-deep stimulation. Therefore, the development and effectiveness of natural fractures are needed for post-fracturing evaluation. Currently, the development of natural fractures is mainly evaluated using imaging logging. Imaging logging can quantitatively interpret the number of fractures, but the development, dip angle, angle of inclusion, and degree of filling of natural fractures all affect their effectiveness. Imaging logging can only identify the number of fractures and is also affected by drilling mud, so it cannot completely and accurately determine the effectiveness of natural fractures.

[0005] The existing methods for assessing the development and effectiveness of natural fractures in ultra-deep fractured reservoirs are insufficient, and post-fracturing assessment techniques need further development and improvement. Summary of the Invention

[0006] The purpose of this invention is to provide a comprehensive post-compression assessment method and system for ultra-deep fractured reservoirs, which solves the problem that current assessment methods for evaluating the degree of natural fracture development and fracture effectiveness in ultra-deep fractured reservoirs are inadequate due to the influence of high temperature and high pressure, and that the assessment results of current assessment methods have low accuracy.

[0007] To achieve the above objectives, the present invention provides a comprehensive post-furlough assessment method for ultra-deep fractured reservoirs, comprising the following steps: Based on data from the fracturing process, the development degree and effectiveness of natural fractures in the reservoir are analyzed and determined. Based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump stop, and the pressure drop of the surface pump stop pressure at the first predetermined time, the development degree and effectiveness of natural fractures are analyzed and determined. Based on the pressure and time data during the post-pressure well test, the development degree and effectiveness of natural fractures are analyzed and determined. Based on data from the fracturing process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, the pressure drop of the surface pump stop pressure within a predetermined time, and the pressure and time data during the post-fracturing well test, a comprehensive analysis is conducted from four aspects to ultimately determine the degree of development and effectiveness of natural fractures.

[0008] Furthermore, based on data from the fracturing process, the development degree and effectiveness of natural fractures in the reservoir are analyzed and determined, including... Based on the construction data during the fracturing operation and the shut-in pressure drop data after the pump is stopped during the fracturing operation, the development degree and effectiveness of the reservoir's natural fractures are analyzed and determined. The construction data includes the time, oil pressure, and discharge rate during the fracturing process.

[0009] Furthermore, the construction data during the fracturing operation and the shut-in pressure drop data are imported into the fracturing numerical modeling software and the G-function module is selected for analysis to obtain the G-function shape; Based on the morphology of the G function, the degree of development and effectiveness of natural cracks are analyzed and determined.

[0010] Furthermore, based on the morphology of the G function, the degree of development and effectiveness of natural cracks are analyzed and determined, including, If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, then the reservoir is judged to have underdeveloped natural fractures and poor effectiveness. If the shape of the G-function curve shows the characteristics of pressure-controlled filtration, then the reservoir is judged to have good natural fracture development and effectiveness. If the G function cannot be calculated, the reservoir is determined to have extremely well-developed and highly effective natural fractures.

[0011] Furthermore, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown includes: Based on the shut-in pressure drop data after pump shutdown during fracturing operations, obtain the instantaneous ground shutdown pressure after pump shutdown. The instantaneous pump stop pressure at the surface after pump shutdown is calculated by adding the wellbore fluid column pressure to the instantaneous pump stop pressure at the bottom of the well, and then subtracting the formation pressure to obtain the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure.

[0012] Furthermore, based on the shut-in pressure drop data after pump shutdown during fracturing operations, the instantaneous surface shutdown pressure after pump shutdown is obtained, including... By installing a pressure monitoring system at the wellhead, the shut-in pressure drop data after the pump is stopped during the fracturing operation is obtained more than the first predetermined time after the well is shut in. The pressure gauge is set to store a value once within a second predetermined time period, and the pressure time interval is adjustable.

[0013] Furthermore, based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, and the pressure drop at the surface after the first predetermined time, the development degree and effectiveness of natural fractures are analyzed and determined, including... If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is less than 5 MPa, then the reservoir's natural fractures are determined to be underdeveloped and have poor effectiveness. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is between 5 and 17 MPa, then the reservoir is determined to have well-developed and effective natural fractures. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is less than 0.5 MPa, then the reservoir's natural fractures are considered to be extremely well-developed and highly effective.

[0014] Furthermore, based on the pressure and time data during the post-pressure well testing process, the development degree and effectiveness of natural fractures are analyzed and determined, including... Based on the pressure and time data during the post-pressure well test, the double logarithmic pressure and derivative curves of the well test curves are obtained; Based on the double logarithmic pressure and derivative curves of the well test curves, obtain the shape of the well test curves and the slope of the later straight line segment of the pressure derivative curve. The development and effectiveness of natural fractures can be determined based on the shape of the well test curve and the slope of the later straight section of the pressure derivative curve.

[0015] Furthermore, based on the morphology of the well test curves and the slope of the later linear segment of the pressure derivative curve, the degree of development and effectiveness of natural fractures are determined, including... If the slope of the straight section of the pressure derivative curve of the well test curve is greater than 1 / 2, it is determined that the reservoir has well-developed natural fractures and good effectiveness. If the slope of the straight section of the pressure derivative curve of the well test is less than 1 / 2, it is determined that the reservoir has poor natural fracture development and effectiveness. If the slope of the straight segment of the pressure derivative curve of the well test curve is between 0.95 and 1, then the reservoir is considered to have extremely well-developed natural fractures and excellent effectiveness.

[0016] Furthermore, the final determination of the development degree and effectiveness of natural cracks includes, If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is less than 5 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is less than 1 / 2, then it is determined that the reservoir natural fractures are not well-developed and have poor effectiveness. If the shape of the G-function curve exhibits the characteristics of pressure-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is between 5 and 17 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is greater than 1 / 2, then it is determined that the reservoir has well-developed natural fractures and good effectiveness. If the G function cannot be calculated, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is less than 0.5 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is between 0.95 and 1, then the reservoir's natural fractures are considered to be extremely well-developed and highly effective.

[0017] The present invention also provides a post-furlough comprehensive judgment system for ultra-deep fractured reservoirs, comprising a first judgment unit, a second judgment unit, a third judgment unit, and a comprehensive judgment unit; The first determination unit is used to analyze and determine the development degree and effectiveness of natural fractures in the reservoir based on data from the fracturing operation process; The second determination unit is used to analyze and determine the development degree and effectiveness of natural fractures based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure and the pressure drop of the surface pump stop pressure over a first predetermined time. The third determination unit is used to analyze and determine the degree of development and effectiveness of natural fractures based on the pressure and time data during the post-pressure well test. The comprehensive judgment unit is used to conduct a comprehensive analysis based on four aspects: data from the fracturing operation process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump stop, the pressure drop of the surface pump stop pressure within a predetermined time, and the pressure and time data during the post-fracturing well test. Ultimately, it determines the degree of development and effectiveness of natural fractures.

[0018] The technical effects and advantages of this invention are as follows: 1. This invention solves the problem of insufficient evaluation methods for the degree of natural fracture development and fracture effectiveness in ultra-deep fractured reservoirs affected by high temperature and pressure, and the low accuracy of current evaluation methods. By utilizing the shape of the G-function curve, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure, the pressure drop of the surface pump stop pressure over 30 minutes, and the slope of the straight line segment of the pressure derivative curve of the well test curve, a simple and accurate evaluation of the degree of natural fracture development and fracture effectiveness in ultra-deep fractured reservoirs is achieved. This invention has been applied in the field to the post-compression analysis and judgment of 40 wells, and the accuracy of the evaluation of the degree of natural fracture development and fracture effectiveness in the reservoir reaches over 95%. Compared with the results of pre-compression reservoir evaluation and post-compression productivity evaluation, this invention proves the accuracy and effectiveness of the technology, and significantly improves the convenience and accuracy of post-compression evaluation of ultra-deep fractured reservoirs. 2. Compared with conventional direct evaluation methods, the analysis and judgment method of this invention has high reliability and effectiveness in post-fracturing evaluation, shortens the operation cycle, reduces construction risks, and has lower operating costs. It can re-understand ultra-deep reservoirs at low cost. Combined with previous fracturing processes and parameters, it can conduct systematic analysis and provide a scientific basis for the improvement of measures and processes in the next stage in this block and similar oilfields.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the steps of a post-pressure comprehensive determination method for ultra-deep fractured reservoirs in an embodiment of the present invention. Figure 2 This is a graph of the G function of well X6 in an embodiment of the present invention; Figure 3 This is a standard curve of the G-function representing the pressure control filtration characteristics in an embodiment of the present invention; Figure 4 This is a standard curve of the G-function for matrix-controlled filtration loss characteristics in an embodiment of the present invention; Figure 5 This is a shut-in pressure drop curve of well X6 in an embodiment of the present invention; Figure 6 This is a double logarithmic pressure and derivative curve of well testing with and without fracture development in an embodiment of the present invention; Figure 7 This is a double logarithmic pressure and derivative curve of well X6 in an embodiment of the present invention; Figure 8 This is a schematic diagram of a post-furlough comprehensive assessment system for ultra-deep fractured reservoirs in an embodiment of the present invention. Detailed Implementation

[0022] 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.

[0023] The example well X6 is an ultra-deep, highly deviated well located in the Kelasu structural belt of the Kuqa Depression. The completed well depth is 7060m (vertical depth 6402.7m), the maximum inclination angle is 76.4°, the formation pressure coefficient is 1.9, the completed stratum is the Cretaceous Bashkichik Formation, and the section to be stimulated is 6805-7020m (inclination thickness 215m / vertical thickness 96.6m), which adopts a general fracturing stimulation technology.

[0024] This invention discloses a comprehensive post-furlough assessment method for ultra-deep fractured reservoirs, such as... Figure 1 As shown, it includes the following steps: S1: Based on data from the fracturing operation, analyze and determine the development degree and effectiveness of natural fractures in the reservoir; specifically, Acquire data such as time, oil pressure, and pumping volume during fracturing operations, and record the shut-in pressure drop data after pump shutdown during fracturing operations; import the acquired data on time, oil pressure, pumping volume, and shut-in pressure after pump shutdown into fracturing numerical modeling software; Among them, fracturing numerical simulation software includes Gohfer, Fracpro, Stimplan, Meyer, etc. Then drag the time scale to select the time period from the instantaneous pump stop pressure to the end of the pressure drop data, select the G function module for analysis, and obtain the shape of the G function curve; Based on the shape of the G-function curve, the development degree and effectiveness of natural fractures in the reservoir are analyzed and determined: If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, it is considered that the reservoir has poor natural fracture development and poor natural fracture effectiveness. If the shape of the G-function curve exhibits the characteristics of pressure-controlled filtration, it is considered that the reservoir has well-developed natural fractures and good natural fracture effectiveness. If the G function cannot be calculated, it is considered that the reservoir has extremely well-developed natural fractures and that the effectiveness of the natural fractures is very high.

[0025] like Figure 2 The figure shows the G-function curve of well X6, referencing... Figure 3 The standard curve of the G function for pressure control filtration characteristics is shown below, and as shown in the figure... Figure 4 The standard G-function curve diagram of the matrix-controlled filtration characteristics shown in the figure reveals that the G-function curve of well X6 exhibits the characteristics of a pressure-controlled filtration curve, suggesting that the reservoir has well-developed natural fractures and good effectiveness of these natural fractures.

[0026] S2: Based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, and the pressure drop of the surface pump stop pressure at the first predetermined time, analyze and determine the development degree and effectiveness of natural fractures; specifically, A pressure monitoring system is installed at the wellhead. After the first predetermined time (30 minutes) after the well is shut in following the fracturing operation, the pressure drop data after the pump is stopped is recorded. The pressure gauge is set to store a value once within a second predetermined time period (1 second to 60 seconds). The pressure time interval is adjustable. Based on the recorded shut-in pressure drop data after pump shutdown during fracturing operations, the instantaneous ground shutdown pressure after pump shutdown was obtained. The instantaneous pump stop pressure at the surface after pump shutdown is calculated by adding the wellbore fluid column pressure to the instantaneous pump stop pressure at the bottom of the well, and then subtracting the formation pressure to obtain the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure. Then monitor the pressure drop of the surface pump shutdown pressure at the first predetermined time (30 minutes). Then, based on the pressure difference between the instantaneous pump shutdown pressure at the bottom of the well and the formation pressure, as well as the pressure drop of the surface pump shutdown pressure at the first predetermined time (30 minutes), analyze and determine the development degree and effectiveness of the natural fractures. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, and the pressure drop at the surface pump stop pressure is less than 5 MPa after 30 minutes, then it is determined that the reservoir has poor natural fracture development and poor natural fracture effectiveness. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, and the pressure drop at the surface pump stop pressure after 30 minutes is between 5 and 17 MPa, then the reservoir is considered to have well-developed natural fractures and good natural fracture effectiveness. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, and the pressure drop at the surface pump stop pressure after 30 minutes is almost 0 (e.g., less than 0.5 MPa), then the reservoir is considered to have extremely well-developed natural fractures and excellent natural fracture effectiveness. like Figure 5 As shown, a pressure monitoring system is installed at the wellhead. After fracturing and shutting in the well for more than 30 minutes, the shut-in pressure drop data is recorded after the pump is stopped. The pressure gauge is set to store values ​​every 1 to 60 seconds, and the pressure time interval is adjustable. The output pressure drop curve is shown in the figure. Figure 5 As shown.

[0027] The instantaneous pump stop pressure at the surface of the well is 71.6 MPa. Adding the fluid column pressure in the wellbore, the instantaneous pump stop pressure at the bottom of the well is 134.3 MPa. The pressure coefficient of the well is 1.9, so the formation pressure is 121.6 MPa. Therefore, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is 12.7 MPa.

[0028] The instantaneous surface pump shutdown pressure was 71.6 MPa, and the surface pump shutdown pressure 30 minutes after well shut-in was 60.8 MPa, resulting in a pressure drop of 10.8 MPa over 30 minutes. Considering the pressure difference of 12.7 MPa between the instantaneous bottomhole pump shutdown pressure and the formation pressure, and the pressure drop of 10.8 MPa over 30 minutes, the analysis concludes that the reservoir has well-developed natural fractures and that these natural fractures are highly effective.

[0029] S3: Based on the pressure and time data during the post-pressure well test, analyze and determine the development degree and effectiveness of natural fractures; specifically, During well completion and production, a storage pressure gauge is inserted at the bottom of the well to record and acquire pressure and time data during well testing, up to the third well opening and the third well shut-in. Based on the pressure and time data during the post-pressure well test, the double logarithmic pressure and derivative curves of the well test are obtained, such as... Figure 6As shown, the shape of the well test curve and the slope of the later straight section of the pressure derivative curve are analyzed. The higher the degree of fracture cutting the matrix, the better the conductivity, and the larger the slope of the later straight section of the pressure derivative curve of the well test curve. This reflects that the reservoir's natural fractures are more developed and more effective. If the slope of the straight section of the pressure derivative curve of the well test curve is greater than 1 / 2, it is considered that the reservoir has well-developed natural fractures and good natural fracture effectiveness. If the slope of the straight section of the pressure derivative curve of the well test curve is less than 1 / 2, it is considered that the reservoir has poor natural fracture development and poor natural fracture effectiveness. If the slope of the straight segment of the pressure derivative curve of the well test curve is close to 1 (e.g., between 0.95 and 1), it is considered that the reservoir has extremely well-developed natural fractures and that the natural fractures are highly effective.

[0030] like Figure 7 As shown, the slope of the straight segment of the pressure derivative curve in the later stage of the well test curve is 0.75, which is between 1 / 2 and 1. The slope of the straight segment of the pressure derivative curve in the well test curve is greater than 1 / 2. The analysis suggests that the reservoir has well-developed natural fractures and good effectiveness of the natural fractures.

[0031] S4: Based on data from the fracturing process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, the pressure drop at the surface after pump shutdown within a predetermined time, and the pressure and time data during the post-fracturing well test, a comprehensive analysis is conducted from these four aspects to ultimately determine the degree of development and effectiveness of natural fractures; specifically, If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time (30 minutes) is less than 5 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is less than 1 / 2, then it is considered that the reservoir natural fractures are not well developed and the effectiveness of natural fractures is poor. If the shape of the G-function curve exhibits the characteristics of pressure-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time (30 minutes) is between 5 and 17 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is greater than 1 / 2, then it is considered that the reservoir has well-developed natural fractures and good natural fracture effectiveness. If the G function cannot be calculated, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time (30 minutes) is almost 0 (e.g., less than 0.5 MPa), and the slope of the straight line segment of the pressure derivative curve of the well test curve is close to 1 (e.g., between 0.95 and 1), then it is considered that the reservoir has extremely well-developed natural fractures and the effectiveness of the natural fractures is excellent.

[0032] This invention also provides a comprehensive post-furlough assessment system for ultra-deep fractured reservoirs, such as... Figure 8As shown, it includes a first determination unit, a second determination unit, a third determination unit, and a comprehensive determination unit; The first determination unit is used to analyze and determine the development degree and effectiveness of natural fractures in the reservoir based on data from the fracturing operation process; The second determination unit is used to analyze and determine the development degree and effectiveness of natural fractures based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure and the pressure drop of the surface pump stop pressure over a first predetermined time. The third determination unit is used to analyze and determine the degree of development and effectiveness of natural fractures based on the pressure and time data during the post-pressure well test. The comprehensive judgment unit is used to comprehensively analyze and judge the development degree and effectiveness of natural fractures based on data from the fracturing operation process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump stop, the pressure drop of the surface pump stop pressure within a predetermined time, and the pressure and time data during the post-fracturing well test.

[0033] Regarding the system in the above embodiments, the specific manner in which each unit module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated here.

[0034] This invention addresses the shortcomings of current methods for evaluating the development and effectiveness of natural fractures in ultra-deep fractured reservoirs due to the influence of high temperature and pressure, and the low accuracy of existing evaluation methods. By utilizing the shape of the G-function curve, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure, the pressure drop at the surface pump stop pressure over 30 minutes, and the slope of the linear segment of the pressure derivative curve of the well test curve, this invention achieves a simple and accurate evaluation of the development and effectiveness of natural fractures in ultra-deep fractured reservoirs. In field applications of this invention in post-fracture analysis of 40 wells, the accuracy of evaluating the development and effectiveness of natural fractures in the reservoir reached over 95%. Comparison with pre-fracture reservoir evaluation and post-fracture productivity evaluation results demonstrates the accuracy and effectiveness of this invention, significantly improving the convenience and accuracy of post-fracture evaluation of ultra-deep fractured reservoirs.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A comprehensive post-furlough assessment method for ultra-deep fractured reservoirs, characterized in that, include: Based on data from the fracturing process, the development degree and effectiveness of natural fractures in the reservoir are analyzed and determined. Based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump stop, and the pressure drop of the surface pump stop pressure at the first predetermined time, the development degree and effectiveness of natural fractures are analyzed and determined. Based on the pressure and time data during the post-pressure well test, the development degree and effectiveness of natural fractures are analyzed and determined. Based on the data from the fracturing operation process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, the pressure drop of the surface pump stop pressure within the predetermined time, and the pressure and time data during the post-fracturing well test, a comprehensive analysis is conducted from four aspects to ultimately determine the degree of development and effectiveness of the natural fractures. Based on data collected during fracturing operations, the development and effectiveness of natural fractures in the reservoir are analyzed and determined, including... Based on the construction data during the fracturing operation and the shut-in pressure drop data after the pump is stopped during the fracturing operation, the development degree and effectiveness of the reservoir's natural fractures are analyzed and determined. The construction data includes the time, oil pressure, and discharge rate during the fracturing process. The construction data and shut-in pressure drop data during the fracturing operation are imported into the fracturing numerical modeling software and analyzed by selecting the G-function module to obtain the G-function shape. Based on the morphology of the G function, the degree of development and effectiveness of natural cracks are analyzed and determined; The final determination of the development degree and effectiveness of natural cracks includes, If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is less than 5 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is less than 1 / 2, then it is determined that the reservoir natural fractures are not well-developed and have poor effectiveness. If the shape of the G-function curve exhibits the characteristics of pressure-controlled filtration, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is between 5 and 17 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is greater than 1 / 2, then it is determined that the reservoir has well-developed natural fractures and good effectiveness. If the G function cannot be calculated, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, the pressure drop of the surface pump stop pressure at the first predetermined time is less than 0.5 MPa, and the slope of the straight line segment of the pressure derivative curve of the well test curve is between 0.95 and 1, then the reservoir's natural fractures are considered to be extremely well-developed and highly effective.

2. The method for comprehensive post-furlough assessment of ultra-deep fractured reservoirs according to claim 1, characterized in that, Based on the morphology of the G function, the degree of development and effectiveness of natural cracks are analyzed and determined, including, If the shape of the G-function curve shows the characteristics of matrix-controlled filtration, then the reservoir is judged to have underdeveloped natural fractures and poor effectiveness. If the shape of the G-function curve shows the characteristics of pressure-controlled filtration, then the reservoir is judged to have good natural fracture development and effectiveness. If the G function cannot be calculated, the reservoir is determined to have extremely well-developed and highly effective natural fractures.

3. The method for comprehensive post-furlough assessment of ultra-deep fractured reservoirs according to claim 1, characterized in that, The pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown includes: Based on the shut-in pressure drop data after pump shutdown during fracturing operations, obtain the instantaneous ground shutdown pressure after pump shutdown. The instantaneous pump stop pressure at the surface after pump shutdown is calculated by adding the wellbore fluid column pressure to the instantaneous pump stop pressure at the bottom of the well, and then subtracting the formation pressure to obtain the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure.

4. The method for comprehensive post-furlough assessment of ultra-deep fractured reservoirs according to claim 3, characterized in that, Based on the shut-in pressure drop data after pump shutdown during fracturing operations, the instantaneous surface shutdown pressure after pump shutdown is obtained. include, By installing a pressure monitoring system at the wellhead, the shut-in pressure drop data after the pump is stopped during the fracturing operation is obtained more than the first predetermined time after the well is shut in. The pressure gauge is set to store a value once within a second predetermined time period, and the pressure time interval is adjustable.

5. A comprehensive post-furlough assessment method for ultra-deep fractured reservoirs according to claim 1, 3, or 4, characterized in that, Based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump shutdown, and the pressure drop at the surface after the first predetermined time, the development degree and effectiveness of natural fractures are analyzed and determined, including... If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is greater than 20 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is less than 5 MPa, then the reservoir's natural fractures are determined to be underdeveloped and have poor effectiveness. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is between 2 and 19 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is between 5 and 17 MPa, then the reservoir is determined to have well-developed and effective natural fractures. If the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure is less than 2 MPa, and the pressure drop of the surface pump stop pressure at the first predetermined time is less than 0.5 MPa, then the reservoir's natural fractures are considered to be extremely well-developed and highly effective.

6. The method for comprehensive post-furlough assessment of ultra-deep fractured reservoirs according to claim 1, characterized in that, Based on the pressure and time data during the post-pressure well test, the development degree and effectiveness of natural fractures are analyzed and determined, including... Based on the pressure and time data during the post-pressure well test, the double logarithmic pressure and derivative curves of the well test curves are obtained; Based on the double logarithmic pressure and derivative curves of the well test curves, obtain the shape of the well test curves and the slope of the later straight line segment of the pressure derivative curve. The development and effectiveness of natural fractures can be determined based on the shape of the well test curve and the slope of the later straight section of the pressure derivative curve.

7. The method for comprehensive post-furlough assessment of ultra-deep fractured reservoirs according to claim 6, characterized in that, Based on the morphology of the well test curve and the slope of the later straight segment of the pressure derivative curve, the development degree and effectiveness of natural fractures are determined, including... If the slope of the straight section of the pressure derivative curve of the well test curve is greater than 1 / 2, it is determined that the reservoir has well-developed natural fractures and good effectiveness. If the slope of the straight section of the pressure derivative curve of the well test is less than 1 / 2, it is determined that the reservoir has poor natural fracture development and effectiveness. If the slope of the straight segment of the pressure derivative curve of the well test curve is between 0.95 and 1, then the reservoir is considered to have extremely well-developed natural fractures and excellent effectiveness.

8. A system for implementing the post-furlough comprehensive determination method for ultra-deep fractured reservoirs according to any one of claims 1-7, characterized in that, It includes a first determination unit, a second determination unit, a third determination unit, and a comprehensive determination unit; The first determination unit is used to analyze and determine the development degree and effectiveness of natural fractures in the reservoir based on data from the fracturing operation process; The second determination unit is used to analyze and determine the development degree and effectiveness of natural fractures based on the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure and the pressure drop of the surface pump stop pressure over a first predetermined time. The third determination unit is used to analyze and determine the degree of development and effectiveness of natural fractures based on the pressure and time data during the post-pressure well test. The comprehensive judgment unit is used to conduct a comprehensive analysis based on four aspects: data from the fracturing operation process, the pressure difference between the instantaneous pump stop pressure at the bottom of the well and the formation pressure after pump stop, the pressure drop of the surface pump stop pressure within a predetermined time, and the pressure and time data during the post-fracturing well test. Ultimately, it determines the degree of development and effectiveness of natural fractures.

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