Method and device for evaluating fracturing transformation effect

Abstract

The invention discloses a method and device for evaluating the fracturing transformation effect, and the method comprises the steps: obtaining the pressure data of a gas well fracturing section after the pump is stopped, and the pressure data is the construction pressure drop second point data recorded after the pump is stopped; converting the pressure data to the well bottom to obtain well bottom pressure drop second point data after the pump is stopped; drawing a double logarithmic curve graph of the pressure and the derivative thereof according to the well bottom pressure drop second point data after the pump is stopped; extracting curve morphological characteristic information in the double logarithmic curve graph of the pressure and the derivative thereof, and determining flow direction characteristics of fluid in the gas well fracturing section according to the curve morphological characteristic information; according to the flow direction characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined, the evaluation result of the fracturing transformation effect can be more reliable, the pertinence and effectiveness of follow-up fracturing construction can be effectively improved, the evaluation cost can be saved while the accuracy of evaluating the fracturing transformation effect is guaranteed, and the evaluation efficiency is improved. The evaluation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a method and a device for evaluating the effect of fracturing transformation. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No admission is made that the description herein is prior art by inclusion in this section.

[0003] As an unconventional natural gas produced from low-porosity and low-permeability reservoir rock systems, shale gas has the characteristics of high mining technology requirements, long mining life, and long production cycle. Over the years, the exploration and development of shale gas has accelerated rapidly, causing some blocks to gradually shift from test evaluation to large-scale development, improving production efficiency while reducing management costs. Large-scale development can not only produce fractures with conductivity, but also communicate natural fractures in the reservoir, thereby forming a complex fracture network, greatly improving the single well production capacity and ultimate recovery rate. Therefore, accurately evaluating the effect of gas well fracturing transformation is a necessary prerequisite for further optimizing engineering transformation parameters, increasing single well production, increasing reserve utilization, and rationally deploying development.

[0004] At present, the evaluation methods of fracturing transformation effects mainly include dynamic monitoring methods and data statistical methods. Dynamic monitoring methods are mainly based on microseismic monitoring, tracer monitoring, optical fiber monitoring and wide-area electromagnetic monitoring. Although these methods have high test accuracy, they are expensive and time-consuming. There are large differences in the applicability of the methods, and there are even contradictions between the results. It is difficult to get a relatively accurate conclusion. The data statistical method mainly depends on the quality of the data and is limited by the amount of data. The analysis effect varies greatly, and it also lacks certain theoretical support.

[0005] Therefore, it is urgent to propose a set of evaluation methods for fracturing transformation effects that have both theoretical basis and strong adaptability. Summary of the invention

[0006] The embodiment of the present invention provides a method for evaluating the effect of hydraulic fracturing, which is used to save evaluation costs, improve evaluation efficiency, and improve the reliability of the evaluation results of hydraulic fracturing while ensuring the accuracy of evaluating the effect of hydraulic fracturing, and can effectively improve the pertinence and effectiveness of subsequent hydraulic fracturing construction. The method includes:

[0007] Obtaining pressure data after the pump is stopped in the fracturing section of the gas well, wherein the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped;

[0008] Convert the pressure data to the bottom of the well to obtain the bottom of the well pressure drop data in seconds after the pump is stopped;

[0009] Based on the second-point data of the bottom hole pressure drop after the pump is stopped, a double logarithmic curve graph of the pressure and its derivative is drawn;

[0010] Extracting curve shape feature information from a double logarithmic curve graph of pressure and its derivative, and determining the flow direction characteristics of the fluid in the fracturing section of the gas well according to the curve shape feature information;

[0011] The fracturing transformation effect of the gas well fracturing section is determined based on the flow characteristics of the fluid in the gas well fracturing section.

[0012] The embodiment of the present invention also provides a device for evaluating the effect of hydraulic fracturing, which is used to save evaluation costs, improve evaluation efficiency, and improve the reliability of the evaluation results of hydraulic fracturing while ensuring the accuracy of evaluating the effect of hydraulic fracturing, and can effectively improve the pertinence and effectiveness of subsequent hydraulic fracturing construction. The device includes:

[0013] A pressure data acquisition module is used to acquire pressure data after the pump is stopped in the fracturing section of the gas well, wherein the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped;

[0014] The pressure data conversion module is used to convert the pressure data to the bottom of the well and obtain the bottom of the well pressure drop data in seconds after the pump is stopped;

[0015] A curve drawing module is used to draw a double logarithmic curve graph of pressure and its derivative according to the second point data of the bottom hole pressure drop after the pump is stopped;

[0016] A flow direction feature determination module is used to extract curve shape feature information in a double logarithmic curve graph of pressure and its derivative, and determine the flow direction feature of the fluid in the gas well fracturing section based on the curve shape feature information;

[0017] The transformation effect determination module is used to determine the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section.

[0018] An embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for evaluating the effect of hydraulic fracturing when executing the computer program.

[0019] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for evaluating the effect of hydraulic fracturing is implemented.

[0020] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for evaluating the effect of hydraulic fracturing is implemented.

[0021] In an embodiment of the present invention, pressure data after the pump is stopped in the gas well fracturing section is obtained, and the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped; the pressure data is converted to the bottom of the well to obtain the bottom hole pressure drop data in seconds after the pump is stopped; based on the bottom hole pressure drop data in seconds after the pump is stopped, a double logarithmic curve graph of the pressure and its derivative is drawn; curve morphology feature information in the double logarithmic curve graph of the pressure and its derivative is extracted, and based on the curve morphology feature information, the flow direction characteristics of the fluid in the gas well fracturing section are determined; based on the flow direction characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined.

[0022] The present invention uses the data of the pump stop pressure drop stage during the fracturing construction process for analysis, and can quickly judge the fracturing transformation effect of the gas well in this section of fracturing and whether pressure channeling occurs between adjacent wells based on the drawn double logarithmic curve. The result is analyzed in coordination with the dynamic monitoring data, so that the evaluation result of the fracturing transformation effect is more reliable, which can effectively improve the pertinence and effectiveness of subsequent fracturing construction, and can save evaluation costs and improve evaluation efficiency while ensuring the accuracy of evaluating the fracturing transformation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 It is a processing flow chart of the evaluation method of the hydraulic fracturing transformation effect in an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of the plane radial flow of fluid in the fracturing stage of a gas well according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the linear flow of fluid in the fracturing section of a gas well according to an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of a well storage flow of a fluid in a fracturing stage of a gas well according to an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of boundary flow of fluid in a gas well fracturing stage according to an embodiment of the present invention;

[0029] Figure 6(1)-Figure 6(3) A schematic diagram of a specific example of the process of determining the fracturing effect by using the double logarithmic curve of pressure and its derivative in an embodiment of the present invention

[0030] Figure 7(1)-Figure 7(3)It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention;

[0031] Figure 8(1)-Figure 8(2) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention;

[0032] Figure 9(1)-Figure 9(2) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention;

[0033] Fig.10 It is a structural schematic diagram of a device for evaluating the effect of hydraulic fracturing in an embodiment of the present invention;

[0034] Fig.11 The figure is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0036] Figure 1 FIG. 1 is a process flow chart of a method for evaluating the effect of hydraulic fracturing in an embodiment of the present invention. Figure 1 As shown, the method for evaluating the effect of hydraulic fracturing in the embodiment of the present invention may include:

[0037] Step 101, obtaining pressure data of a gas well fracturing section after pumping is stopped, wherein the pressure data is the construction pressure drop data recorded at the second point after pumping is stopped;

[0038] Step 102, convert the pressure data to the bottom of the well to obtain the bottom of the well pressure drop data after the pump is stopped;

[0039] Step 103, drawing a double logarithmic curve graph of pressure and its derivative according to the second point data of the bottom hole pressure drop after the pump is stopped;

[0040] Step 104, extracting curve shape feature information from the double logarithmic curve graph of pressure and its derivative, and determining the flow direction characteristics of the fluid in the gas well fracturing section according to the curve shape feature information;

[0041] Step 105: Determine the fracturing effect of the gas well fracturing section according to the flow characteristics of the fluid in the gas well fracturing section.

[0042] Generally, the change of pressure over time is often displayed in a graphical form, which can be drawn into a rectangular coordinate graph of pressure and time, a single logarithmic graph, a double logarithmic curve graph of pressure and its derivative, etc. Since the double logarithmic graph can best reflect the reservoir seepage characteristics, the present invention analyzes the pump stop pressure drop data through a double logarithmic curve graph. However, under different physical models and seepage state conditions, the drawn double logarithmic pressure graphs are also different.

[0043] In order to evaluate the fracturing effect of the gas well fracturing section, a double logarithmic curve graph of pressure and its derivative can be drawn through the pressure data after the pump is stopped in the gas well fracturing section, and the double logarithmic curve graph of pressure and its derivative can be analyzed.

[0044] First, the pressure data after the pump is stopped in the gas well fracturing section can be obtained, where the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped; then the pressure data is converted to the bottom of the well to obtain the bottom hole pressure drop data in seconds after the pump is stopped; and then, based on the bottom hole pressure drop data in seconds after the pump is stopped, a double logarithmic curve graph of pressure and its derivative is drawn.

[0045] Next, the double logarithmic curve graph of pressure and its derivative is analyzed to extract the curve morphological characteristic information in the double logarithmic curve graph of pressure and its derivative. Then, based on the curve morphological characteristic information, the flow direction characteristics of the fluid in the gas well fracturing section are determined. Finally, based on the flow direction characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined.

[0046] In one implementation, the flow direction characteristics of the fluid in the gas well fracturing section may include one of the following characteristics: radial flow characteristics, linear flow characteristics, well storage flow characteristics, and boundary flow characteristics.

[0047] The following introduces the different flow characteristics of fluids in the fracturing section of a gas well.

[0048] Figure 2 FIG. 1 is a schematic diagram of the planar radial flow of fluid in the gas well fracturing section according to an embodiment of the present invention. Figure 2 As shown in the figure, assuming that the formation is homogeneous and of equal thickness, and the gas well opens the entire formation, that is, the fluid in the formation flows from all sides to the bottom of the well along the horizontal plane. At this time, it can be regarded as any horizontal plane in the formation perpendicular to the wellbore, and the streamlines always converge from all directions to the wellbore. This is a plane radial flow, which is a typical unstable flow state, indicating that the reservoir near the bottom of the well is generally homogeneous within this range, and the reservoir properties are good. The plane radial flow is manifested on the double logarithmic pressure graph as a horizontal straight line of the derivative line segment, that is, the slope of the pressure derivative curve is 0.

[0049] Figure 3 FIG. 1 is a schematic diagram of the linear flow of fluid in the fracturing section of a gas well according to an embodiment of the present invention. Figure 3As shown in the figure, the reservoir fluid flows linearly in a direction perpendicular to the wellbore, often forming a single main fracture perpendicular to the wellbore. At this time, the permeability in the fracture is generally very large, forming the so-called "infinite conductivity fracture". It is precisely because the streamlines formed are parallel, so the isobaric surface should be a plane. The linear flow is manifested on the double logarithmic pressure graph as a pressure derivative curve with a slope of 0.5.

[0050] Figure 4 FIG. 1 is a schematic diagram of the well storage flow of the fluid in the fracturing stage of a gas well in an embodiment of the present invention, as shown in FIG. Figure 4 As shown in the figure, when the well is first opened, the wellbore is full of liquid, and the fluid can only be discharged by the pressure drop caused by expansion, which is the wellbore storage effect. At the same time, the gas well production only comes from the expansion of the fluid stored in or around the wellbore, and the reservoir has almost no contribution. The performance of the well storage flow on the double logarithmic pressure graph is that the pressure and pressure derivative curves are almost coincident, and the slope is 1.

[0051] Figure 5 FIG. 1 is a schematic diagram of the boundary flow of the fluid in the fracturing section of a gas well according to an embodiment of the present invention. Figure 5 As shown in the figure, assuming that the gas well is in a closed block, the pressure will later spread to all the surrounding boundaries, and then the pressure at each point in the closed block will drop at the same speed, forming a quasi-steady-state flow. At this time, the pressure has spread to the entire control range. The boundary flow on the double logarithmic pressure graph is a straight line with a slope of 1 at the tail of the pressure derivative, where r represents the bottom radius of the well, P wf Indicates the bottom hole flowing pressure.

[0052] The fracturing effect of the gas well fracturing section can be determined based on the flow direction characteristics of the fluid in the gas well fracturing section.

[0053] In one embodiment, determining the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section may include: when the flow direction of the fluid in the gas well fracturing section presents radial flow characteristics, determining the fracturing transformation effect of the gas well fracturing section as a primary fracturing transformation effect, wherein the primary fracturing transformation effect represents the best fracturing transformation effect.

[0054] In one embodiment, determining the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section may include: when the flow direction of the fluid in the gas well fracturing section presents a linear flow characteristic, determining that the fracturing transformation effect of the gas well fracturing section is a secondary fracturing transformation effect, wherein the secondary fracturing transformation effect represents a good fracturing transformation effect.

[0055] In one embodiment, determining the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section may include: when the flow direction of the fluid in the gas well fracturing section presents the well storage flow characteristics, determining that the fracturing transformation effect of the gas well fracturing section is a third-level fracturing transformation effect, wherein the third-level fracturing transformation effect represents a poor fracturing transformation effect.

[0056] In one embodiment, determining the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section can include: when the flow direction of the fluid in the gas well fracturing section presents boundary flow characteristics, determining that the fracturing transformation effect of the gas well fracturing section is a fourth-level fracturing transformation effect, wherein the fourth-level fracturing transformation effect characterizes the existence of inter-well pressure channeling in the gas well fracturing section.

[0057] In specific implementation, by observing the curve morphology characteristic information of the double logarithmic curve graph of pressure and its derivative, the fracturing transformation effect of the gas well fracturing section or the pressure channeling between wells can be further analyzed:

[0058] If the derivative curve in the double logarithmic pressure diagram shows radial flow characteristics, it means that the fracturing fluid enters the reservoir around the fracturing section in a radial flow manner, the fracturing network is large in volume, highly complex, and the reservoir transformation effect is good; if the derivative curve in the double logarithmic pressure diagram shows linear flow characteristics, it means that the artificial fractures formed by fracturing tend to be a single main fracture, the transformation volume is large, and the reservoir transformation effect is good; if the derivative curve in the double logarithmic pressure diagram shows well storage flow characteristics, it means that complex fractures have not yet been formed in the fracturing section, the seepage capacity is weak, and the reservoir transformation effect is poor; if the derivative curve in the double logarithmic pressure diagram shows boundary flow characteristics, then a classified discussion should be conducted: If the gas well is a single well and there is no interference from other gas wells around it, then the following will occur: Figure 4 The situation shown is that due to the influence of the boundary, the physical properties of the outer zone deteriorate, the flow is obstructed, and the pressure gradient increases, so that the derivative curve in the pressure double logarithmic diagram deviates from the radial flow straight line and tilts upward; if the gas well is a platform well and there are other gas wells interfering around it, then the boundary flow at the tail of the curve is affected by the pressure channeling between wells. The pressure of the adjacent well is higher than that of the positive fracturing well, and the pressure gradient increases, so that the derivative curve in the pressure double logarithmic diagram deviates from the radial flow straight line and tilts upward.

[0059] In summary, the shape of the derivative curve in the double logarithmic pressure diagram can be used to simply and quickly judge the fracturing effect of the fracturing section and whether pressure channeling occurs between adjacent wells.

[0060] The specific identification steps can be as follows:

[0061] (1) Obtain the pressure data after the pump is stopped in the gas well fracturing section, that is, the construction pressure drop data recorded at the second point after the pump is stopped.

[0062] (2) Convert the construction pressure drop data in seconds to the bottom of the well to obtain the bottom of the well pressure drop data in seconds after the pump is stopped.

[0063] (3) Based on the second-point data of the bottom hole pressure drop after the pump is stopped (hereinafter referred to as the pump stop pressure drop data), a double logarithm and derivative curve of pressure are drawn.

[0064] (4) Observe the shape of the double logarithmic and derivative curves of pressure and determine the characteristic flow stage to which the curve belongs, that is, determine whether the shape of the derivative curve in the double logarithmic pressure diagram of the fracturing section is one of the radial flow / linear flow / well storage flow / boundary flow stages.

[0065] (5) If the derivative curve in the double logarithmic pressure diagram shows radial flow characteristics, further: combined with microseismic monitoring data, it is observed that the microseismic monitoring event points in this section are numerous and complex; combined with distributed optical fiber production profile test or tracer production profile test, it is observed that the gas production contribution of this section is high. Comprehensive comparison and verification of the high matching degree indicate that the fracturing transformation effect of this section is good.

[0066] (6) If the derivative curve in the double logarithmic pressure graph shows linear flow characteristics, further: combined with microseismic monitoring data, it is observed that there are many microseismic monitoring event points in this section and they are evenly distributed; combined with distributed optical fiber production profile test or tracer production profile test, it is observed that the gas production contribution of this section is relatively high. Comprehensive comparison and verification of the high matching degree indicate that the fracturing transformation effect of this section is good.

[0067] (7) If the derivative curve in the double logarithmic pressure diagram shows the characteristics of well storage flow, further: combined with microseismic monitoring data, it is observed that there are few microseismic monitoring event points in this section; combined with distributed optical fiber production profile test or tracer production profile test, it is observed that the gas production contribution of this section is low. Comprehensive comparison and verification of the high matching degree indicate that the fracturing transformation effect of this section is poor.

[0068] (8) If the derivative curve in the double logarithmic pressure diagram shows boundary flow characteristics, further: combined with microseismic monitoring data, it is observed that there are more microseismic monitoring event points in this section and they are more offset toward the adjacent wells; combined with the pressure response data of the adjacent wells, it is observed that the pressure increase of the adjacent wells in this section is more than 10MPa, which is considered to be a large increase in the pressure of the adjacent wells. The comprehensive comparison verifies that the matching degree is high, indicating that there may be pressure channeling between wells in this section of fracturing.

[0069] The beneficial effects of the present invention are as follows:

[0070] (1) The present invention can quickly judge the fracturing transformation effect of the fracturing section and whether pressure channeling occurs between adjacent wells by observing the double logarithm and derivative curves of pressure drawn based on the pump-off pressure data during the fracturing stage. The operation cost is low, and it is easy to use and has little difficulty.

[0071] (2) In addition to evaluating and analyzing the fracturing effect of the fracturing section of a shale gas well and quickly determining the pressure channeling between wells, the present invention can also collaboratively verify and jointly analyze other dynamic data during the fracturing stage, such as microseismic monitoring, distributed optical fiber production profile monitoring, and pressure increase data of adjacent wells, thereby improving and compensating for the defects of large differences in adaptability and inconsistent analysis results in the evaluation methods of fracturing effect, and greatly improving the accuracy of the evaluation results of the fracturing effect of shale gas wells.

[0072] Therefore, the method of the present invention is simple, practical, economical, fast and efficient, and has certain guiding significance for the construction work in the fracturing stage of shale gas wells.

[0073] The following examples use the method of the present invention to illustrate the process of simply and quickly judging the fracturing effect of the fracturing section and whether pressure channeling occurs between adjacent wells by using the derivative curve shape in the double logarithmic pressure diagram.

[0074] Figure 6(1)-Figure 6(3) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention.

[0075] The fracturing section of the shale gas well is located in the Longmaxi Formation, with a well depth of 4752-4690m, a vertical depth of 4253m, and a section length of 62m. Figure 6 (1) shows the double logarithmic and derivative curves of pressure drawn based on the second-point data of the bottom hole pressure drop after the pump was stopped in this section. It can be preliminarily determined that the curve exhibits radial flow characteristics. Further, the microseismic monitoring data of this section was obtained, as shown in Figure 6 (2), and it was observed that there were many microseismic event points in this section and the distribution showed obvious unevenness. Further, the distributed optical fiber test data of each section of the well was obtained, as shown in Figure 6 (3), and it was observed that the distributed optical fiber gas production profile of this section (pure black bar graph, bold numbers) accounted for a larger proportion than other fracturing sections, indicating that the gas production contribution of this section accounted for a higher proportion (7.1). In summary, it can be judged that the fracturing transformation effect of this fracturing section is good.

[0076] Figure 7(1)-Figure 7(3) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention.

[0077] The fracturing section of the shale gas well is located in the Longmaxi Formation, with a well depth of 4814-4752m, a vertical depth of 4253m, and a section length of 62m. Figure 7(1) shows the double logarithm and derivative curves of pressure drawn based on the second-point data of the bottom hole pressure drop after the pump was stopped in this section. It can be preliminarily determined that the curve exhibits linear flow characteristics. Further, the microseismic monitoring data of this section was obtained, as shown in Figure 7(2), and it was observed that there were many microseismic event points in this section and they were obviously distributed along the natural fractures of the vertical wellbore. Further, the distributed optical fiber test data of each section of the well was obtained, as shown in Figure 7(3), and it was observed that the distributed optical fiber gas production profile of this section (bold) (this section is marked in pure black in the bar chart, and the number 7.1 on the top is also bolded) occupies the middle position among all the fracturing sections, indicating that the gas production contribution of this section is medium to high (5.7). In summary, it can be judged that the fracturing transformation effect of this fracturing section is good, but not as good as that of the above. Figure 6(1)-Figure 6(3) Embodiment of the invention.

[0078] Figure 8(1)-Figure 8(2) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention.

[0079] The fracturing section of the shale gas well is located in the Wujiaping Formation, with a well depth of 5590-5645m, a vertical depth of 3730-3725m, and a section length of 55m. Figure 8(1) shows the double logarithm and derivative curves of pressure drawn based on the second-point data of the bottom hole pressure drop after the pump was stopped. It can be preliminarily determined that the curve shows the characteristics of well flow storage. Furthermore, the microseismic monitoring data of this section was obtained, as shown in Figure 8(2), and it was observed that there were very few microseismic event points in this section, which were scattered. In summary, it can be determined that the fracturing transformation effect of this fracturing section is poor.

[0080] Figure 9(1)-Figure 9(2) It is a schematic diagram of a specific example of the process of determining the effect of hydraulic fracturing through the double logarithmic curve of pressure and its derivative in an embodiment of the present invention.

[0081] The fracturing section of the shale gas well is located in the Longmaxi Formation, with a segmented well depth of 5752-5689m, a vertical depth of 3936-3941m, and a segment length of 63m.

[0082] Figure 9(1) shows the double logarithm and derivative curves of pressure drawn based on the second-point data of the bottom hole pressure drop after the pump was stopped. It can be preliminarily determined that the curve exhibits boundary flow characteristics. Furthermore, the microseismic monitoring data of this section was obtained, as shown in Figure 9(2), and it was observed that the microseismic event points of this section were all offset toward the adjacent wells. Furthermore, it was obtained that the pressure increase of the adjacent wells during the fracturing of this section was 10.74MPa, and it was determined that the pressure increase of the adjacent wells was large. In summary, it can be determined that pressure channeling occurred with the adjacent wells during the fracturing process of this fracturing section.

[0083] The present invention also provides a device for evaluating the effect of hydraulic fracturing, as described in the following embodiments. Since the principle of the device to solve the problem is similar to the method for evaluating the effect of hydraulic fracturing, the implementation of the device can refer to the implementation of the method for evaluating the effect of hydraulic fracturing, and the repeated parts will not be repeated.

[0084] Fig.10 FIG. 1 is a schematic diagram of the structure of the evaluation device for the fracturing transformation effect in an embodiment of the present invention. Fig.10 As shown, the evaluation device for the fracturing transformation effect in the embodiment of the present invention may specifically include:

[0085] The pressure data acquisition module 1001 is used to acquire the pressure data after the pump is stopped in the fracturing stage of the gas well, and the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped;

[0086] The pressure data conversion module 1002 is used to convert the pressure data to the bottom of the well, and obtain the bottom of the well pressure drop second data after the pump is stopped;

[0087] The curve drawing module 1003 is used to draw a double logarithmic curve graph of pressure and its derivative according to the second point data of the bottom hole pressure drop after the pump is stopped;

[0088] The flow direction characteristic determination module 1004 is used to extract the curve shape characteristic information in the double logarithmic curve diagram of pressure and its derivative, and determine the flow direction characteristics of the fluid in the gas well fracturing section according to the curve shape characteristic information;

[0089] The transformation effect determination module 1005 is used to determine the fracturing transformation effect of the gas well fracturing section according to the flow characteristics of the fluid in the gas well fracturing section.

[0090] In one embodiment, the flow direction characteristics of the fluid in the gas well fracturing section may include one of the following characteristics: radial flow characteristics, linear flow characteristics, well storage flow characteristics and boundary flow characteristics.

[0091] In one embodiment, the transformation effect determination module 1005 is specifically used to:

[0092] When the flow direction of the fluid in the gas well fracturing section presents radial flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a primary fracturing transformation effect, wherein the primary fracturing transformation effect represents the best fracturing transformation effect.

[0093] In one embodiment, the transformation effect determination module 1005 is specifically used to:

[0094] When the flow direction of the fluid in the gas well fracturing section presents a linear flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a secondary fracturing transformation effect, wherein the secondary fracturing transformation effect represents a good fracturing transformation effect.

[0095] In one embodiment, the transformation effect determination module 1005 is specifically used to:

[0096] When the flow direction of the fluid in the gas well fracturing section presents the well storage flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a three-level fracturing transformation effect, wherein the three-level fracturing transformation effect represents a poor fracturing transformation effect.

[0097] In one embodiment, the transformation effect determination module 1005 is specifically used to:

[0098] When the flow direction of the fluid in the gas well fracturing section presents boundary flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a four-stage fracturing transformation effect, wherein the four-stage fracturing transformation effect represents the situation where inter-well pressure channeling exists in the gas well fracturing section.

[0099] Based on the above invention concept, Fig.11 As shown, the present invention also proposes a computer device 1100, including a memory 1110, a processor 1120, and a computer program 1130 stored in the memory 1110 and executable on the processor 1120, wherein the processor 1120 implements the aforementioned method for evaluating the effect of hydraulic fracturing when executing the computer program 1130.

[0100] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for evaluating the effect of hydraulic fracturing is implemented.

[0101] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for evaluating the effect of hydraulic fracturing is implemented.

[0102] To summarize, in an embodiment of the present invention, pressure data after the pump is stopped in the gas well fracturing section is obtained, and the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped; the pressure data is converted to the bottom of the well to obtain the bottom hole pressure drop data in seconds after the pump is stopped; based on the bottom hole pressure drop data in seconds after the pump is stopped, a double logarithmic curve graph of the pressure and its derivative is drawn; the curve morphology feature information in the double logarithmic curve graph of the pressure and its derivative is extracted, and based on the curve morphology feature information, the flow direction characteristics of the fluid in the gas well fracturing section are determined; based on the flow direction characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined.

[0103] The present invention uses the data of the pump stop pressure drop stage during the fracturing construction process for analysis, and can quickly judge the fracturing transformation effect of the gas well in this section of fracturing and whether pressure channeling occurs between adjacent wells based on the drawn double logarithmic curve. The result is analyzed in coordination with the dynamic monitoring data, so that the evaluation result of the fracturing transformation effect is more reliable, which can effectively improve the pertinence and effectiveness of subsequent fracturing construction, and can save evaluation costs and improve evaluation efficiency while ensuring the accuracy of evaluating the fracturing transformation effect.

[0104] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0105] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0106] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0108] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating the effect of hydraulic fracturing, characterized in that: include: Obtaining pressure data after the pump is stopped in the fracturing section of the gas well, wherein the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped; Convert the pressure data to the bottom of the well to obtain the bottom of the well pressure drop data in seconds after the pump is stopped; Based on the second-point data of the bottom hole pressure drop after the pump is stopped, a double logarithmic curve graph of the pressure and its derivative is drawn; Extracting curve shape feature information from a double logarithmic curve graph of pressure and its derivative, and determining the flow direction characteristics of the fluid in the fracturing section of the gas well according to the curve shape feature information; The fracturing transformation effect of the gas well fracturing section is determined based on the flow characteristics of the fluid in the gas well fracturing section.

2. The method according to claim 1, characterized in that The flow characteristics of the fluid in the gas well fracturing section include one of the following characteristics: Radial flow characteristics, linear flow characteristics, well storage flow characteristics and boundary flow characteristics.

3. The method according to claim 1, characterized in that According to the flow characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined, including: When the flow direction of the fluid in the gas well fracturing section presents radial flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a primary fracturing transformation effect, wherein the primary fracturing transformation effect represents the best fracturing transformation effect.

4. The method according to claim 1, characterized in that According to the flow characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined, including: When the flow direction of the fluid in the gas well fracturing section presents a linear flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a secondary fracturing transformation effect, wherein the secondary fracturing transformation effect represents a good fracturing transformation effect.

5. The method according to claim 1, characterized in that According to the flow characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined, including: When the flow direction of the fluid in the gas well fracturing section presents the well storage flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a three-level fracturing transformation effect, wherein the three-level fracturing transformation effect represents a poor fracturing transformation effect.

6. The method according to claim 1, characterized in that According to the flow characteristics of the fluid in the gas well fracturing section, the fracturing transformation effect of the gas well fracturing section is determined, including: When the flow direction of the fluid in the gas well fracturing section presents boundary flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a four-stage fracturing transformation effect, wherein the four-stage fracturing transformation effect represents the situation where inter-well pressure channeling exists in the gas well fracturing section.

7. A device for evaluating the effect of hydraulic fracturing, characterized in that: include: A pressure data acquisition module is used to acquire pressure data after the pump is stopped in the fracturing section of the gas well, wherein the pressure data is the construction pressure drop data recorded in seconds after the pump is stopped; The pressure data conversion module is used to convert the pressure data to the bottom of the well and obtain the bottom of the well pressure drop data in seconds after the pump is stopped; A curve drawing module is used to draw a double logarithmic curve graph of pressure and its derivative according to the second point data of the bottom hole pressure drop after the pump is stopped; A flow direction feature determination module is used to extract curve shape feature information in a double logarithmic curve graph of pressure and its derivative, and determine the flow direction feature of the fluid in the gas well fracturing section based on the curve shape feature information; The transformation effect determination module is used to determine the fracturing transformation effect of the gas well fracturing section according to the flow direction characteristics of the fluid in the gas well fracturing section.

8. The device according to claim 7, characterized in that The flow characteristics of the fluid in the gas well fracturing section include one of the following characteristics: Radial flow characteristics, linear flow characteristics, well storage flow characteristics and boundary flow characteristics.

9. The device according to claim 7, characterized in that The fracturing transformation effect determination module is specifically used for: When the flow direction of the fluid in the gas well fracturing section presents radial flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a primary fracturing transformation effect, wherein the primary fracturing transformation effect represents the best fracturing transformation effect.

10. The device according to claim 7, characterized in that The fracturing transformation effect determination module is specifically used for: When the flow direction of the fluid in the gas well fracturing section presents a linear flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a secondary fracturing transformation effect, wherein the secondary fracturing transformation effect represents a good fracturing transformation effect.

11. The device according to claim 7, characterized in that The fracturing transformation effect determination module is specifically used for: When the flow direction of the fluid in the gas well fracturing section presents the well storage flow characteristic, the fracturing transformation effect of the gas well fracturing section is determined to be a three-level fracturing transformation effect, wherein the three-level fracturing transformation effect represents a poor fracturing transformation effect.

12. The device according to claim 7, characterized in that The fracturing transformation effect determination module is specifically used for: When the flow direction of the fluid in the gas well fracturing section presents boundary flow characteristics, the fracturing transformation effect of the gas well fracturing section is determined to be a four-stage fracturing transformation effect, wherein the four-stage fracturing transformation effect represents the situation where inter-well pressure channeling exists in the gas well fracturing section.

13. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

15. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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