Gas storage sealing performance detection method, device, medium and equipment

Abstract

The invention provides a gas storage sealing performance detection method and device, a medium and equipment. The gas storage sealing performance detection method comprises the steps that unstable well testing is conducted on a target well group in a gas storage, a first well test interpretation curve chart for representing the influence of the water body outside the fault on the sealing performance of the gas storage along with the injection-production period is obtained; the second well testing interpretation curve chart is used for representing the influence of inter-well interference on the sealing performance of the gas storage along with the injection-production period; the third well testing interpretation curve chart is used for representing the influence of boundary form response on the sealing performance of the gas storage along with the injection-production period; the change rules of the first well test interpretation curve chart, the second well test interpretation curve chart and the third well test interpretation curve chart can truly restore the geological environment of the gas storage, so that the sealing performance of the gas storage is detected based on the well test interpretation curve charts; the influence of fault external water body conduction, adjacent well interference and boundary form response on the sealing performance of the gas storage can be precisely explained, and then whether the sealing performance of the gas storage meets the requirement or not can be accurately detected.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas reservoir development, and in particular to a method, device, medium and equipment for detecting the sealing performance of a gas storage reservoir. Background Art

[0002] Gas storage has the function of peak load regulation and improving pipeline transportation efficiency. It can effectively regulate gas supply, alleviate seasonal imbalance in gas consumption, reduce the harmful effects of fluctuations in gas consumption on the economy and residents' lives, ensure the smooth operation of pipelines, and improve pipeline transportation efficiency. At the same time, gas storage also has the functions of emergency reserve and strategic reserve, which can improve the reliability and continuity of long-distance pipeline networks. When the gas source or upstream gas transmission system fails or the gas transmission is interrupted due to system maintenance, the gas storage can ensure continuous gas supply and ensure the normal operation of the system. As a long-term reserve of natural gas in countries and regions, it mainly responds to regional natural gas supply interruptions or shortages.

[0003] An underground gas storage is an underground structure (including natural or artificial structures) used to store natural gas. It is an artificial gas field or gas reservoir formed by re-injecting natural gas extracted from a natural gas field into the underground space. Types of underground gas storage include oil and gas reservoir type, aquifer structure type, salt cavern type, and mine pit type. The oil and gas reservoir type is the main type at home and abroad. It is the easiest type to build a storage facility by reconstructing existing oil or gas fields. However, the sealing of the gas storage is crucial and is a key factor in the safe operation of the gas storage facility.

[0004] However, there is currently no very effective method to detect the sealing of gas storage reservoirs, which affects the operating safety of gas storage reservoirs and the operating costs of oil fields. Summary of the invention

[0005] In view of the problems existing in the prior art, the embodiments of the present invention provide a method, device, medium and equipment for detecting the sealing performance of a gas storage reservoir, so as to solve or partially solve the technical problem that the sealing performance of an oilfield gas storage reservoir cannot be accurately detected, thereby affecting the safe operation of the gas storage reservoir.

[0006] A first aspect of the present invention provides a method for detecting the sealing performance of a gas storage reservoir, the method comprising:

[0007] Using the pre-built well test model, an unstable well test is performed on the target well group in the gas storage reservoir, and a first well test interpretation curve plate for characterizing the influence of the water body outside the fault on the sealing of the gas storage reservoir with the injection and production cycle, a second well test interpretation curve plate for characterizing the influence of the well-to-well interference on the sealing of the gas storage reservoir with the injection and production cycle, or a third well test interpretation curve plate for characterizing the influence of the boundary morphology response on the sealing of the gas storage reservoir with the injection and production cycle is obtained;

[0008] The sealing performance of the gas storage reservoir is tested according to the first well test interpretation curve plate, the second well test interpretation curve plate or the third well test interpretation curve plate to obtain a gas storage reservoir sealing performance test result.

[0009] In the above scheme, the first well test interpretation curve chart includes a first normalized pressure curve corresponding to multiple rounds and a first normalized pressure derivative curve corresponding to multiple rounds; the sealing of the gas storage reservoir is tested according to the first well test interpretation curve chart to obtain a first test result, including:

[0010] As the number of rounds increases, if the inflection point where the first regularized pressure curve turns to a horizontal line decreases in height, and the arrival time of the downward inflection point of the first regularized pressure derivative curve is advanced, it is determined that the first detection result is that the gas storage reservoir is unqualified in sealing.

[0011] In the above solution, the second well test interpretation curve chart includes pressure curves corresponding to multiple rounds; the gas storage reservoir sealing is tested according to the second well test interpretation curve chart to obtain a second test result, including:

[0012] In each round, when the well is shut down or the production is reduced, if the pressure curve shows an upward trend or it is determined that the downward trend of the pressure curve slows down, the second test result is determined to be that the gas storage reservoir is unqualified in sealing;

[0013] In each round, when the well is stimulated to be opened or the production is increased, if the pressure curve shows a downward trend or it is determined that the upward trend of the pressure curve slows down, the second test result is determined to be that the sealing of the gas storage reservoir is unqualified.

[0014] In the above scheme, the third well test interpretation curve chart includes third normalized pressure curves corresponding to multiple rounds and third normalized pressure derivative curves corresponding to multiple rounds; the third test result is obtained by testing the sealing performance of the gas storage reservoir according to the third well test interpretation curve chart, including:

[0015] As the rounds increase, if the arrival time of the 0.5 horizontal line inflection point in the third normalized pressure derivative curve is delayed and the end horizontal line height of the third normalized pressure derivative curve rises, it is determined that the third test result is that the gas storage reservoir sealing is unqualified.

[0016] In the above solution, after testing the sealing performance of the gas storage reservoir according to the third well test interpretation curve chart and obtaining the third test result, the method further includes:

[0017] Determine the reservoir exploration radius for each round;

[0018] If it is determined that the corresponding reservoir detection radius shows an increasing trend with the increase in rounds, then the third detection result is determined to be that the sealing of the gas storage reservoir is unqualified.

[0019] In the above scheme, the determination of the reservoir detection radius of each round includes:

[0020] According to the formula Determine the reservoir detection radius L d ;in,

[0021] k is the formation permeability, t is the pressure transmission time, φ is the reservoir porosity, μ is the fluid viscosity, and C t is the comprehensive compression factor.

[0022] A second aspect of the present invention provides a gas storage reservoir sealing detection device, the device comprising:

[0023] A well testing unit is used to perform unstable well testing on a target well group in a gas storage reservoir using a pre-built well testing model, and obtain a first well testing interpretation curve plate for characterizing the influence of water outside the fault on the sealing of the gas storage reservoir along with the injection and production cycle, a second well testing interpretation curve plate for characterizing the influence of well-to-well interference on the sealing of the gas storage reservoir along with the injection and production cycle, or a third well testing interpretation curve plate for characterizing the influence of boundary morphological response on the sealing of the gas storage reservoir along with the injection and production cycle;

[0024] The detection unit is used to detect the sealing performance of the gas storage reservoir according to the first well test interpretation curve chart, the second well test interpretation curve chart or the third well test interpretation curve chart to obtain the sealing performance detection result of the gas storage reservoir.

[0025] In the above scheme, the first well test interpretation curve chart includes first normalized pressure curves corresponding to multiple rounds and first normalized pressure derivative curves corresponding to multiple rounds; the detection unit is specifically used for:

[0026] As the number of rounds increases, if it is determined that the inflection point of the end of the first regularized pressure curve turning into a horizontal line moves to the left, and it is determined that the inflection point of the end of the first regularized pressure derivative curve drops and moves to the left, then the first test result is determined to be that the sealing of the gas storage reservoir is unqualified.

[0027] According to a third aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps of any one of the methods described in the first aspect are implemented.

[0028] According to a fourth aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any one of the methods described in the first aspect are implemented.

[0029] The present invention provides a gas storage reservoir sealing detection method, device, medium and equipment. The method comprises: using a pre-constructed well test model to perform an unstable well test on a target well group in the gas storage reservoir, and obtaining a first well test interpretation curve plate for characterizing the influence of water outside the fault on the sealing of the gas storage reservoir along with the injection and production cycle, a second well test interpretation curve plate for characterizing the influence of well-to-well interference on the sealing of the gas storage reservoir along with the injection and production cycle, or a third well test interpretation curve plate for characterizing the influence of boundary morphological response on the sealing of the gas storage reservoir along with the injection and production cycle; testing the sealing of the gas storage reservoir according to the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate, and obtaining a gas storage reservoir sealing detection result. Thus, since the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate are all generated according to the unstable well test during the high-speed injection and production stage of the gas storage, the changing rules of the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate can truly restore the geological environment in which the gas storage is located. Then, when the sealing of the gas storage is detected based on the first well test interpretation curve plate, the second well test interpretation curve plate or the third well test interpretation curve plate, the influence of the conduction of water outside the fault, the interference of adjacent wells and the boundary morphological response on the sealing of the gas storage can be precisely interpreted, so as to accurately detect whether the sealing of the gas storage meets the requirements and ensure the safe operation of the gas storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0031] Figure 1 A schematic diagram of a method for detecting the sealing performance of a gas storage reservoir according to an embodiment of the present invention is shown;

[0032] Figure 2 A schematic diagram of a normalized pressure curve and a normalized pressure derivative curve obtained after a single unstable well test is performed on a target well according to an embodiment of the present invention is shown;

[0033] Figure 3 A schematic diagram showing the division of flow stages obtained after an unstable well test according to an embodiment of the present invention is shown;

[0034] Figure 4 A schematic diagram of an exciting well and an observation well according to an embodiment of the present invention is shown;

[0035] Figure 5A schematic diagram of a pressure curve generated by an interference well test according to an embodiment of the present invention is shown;

[0036] Figure 6 A schematic diagram of a first well test interpretation curve chart according to an embodiment of the present invention is shown;

[0037] Figure 7 A schematic diagram of a third well test interpretation curve chart according to an embodiment of the present invention is shown;

[0038] Figure 8 A schematic structural diagram of a gas storage reservoir sealing detection device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0039] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0040] The present invention provides a method for detecting the sealing performance of a gas storage reservoir. Figure 1 As shown, the method mainly includes the following steps:

[0041] S110, using a pre-constructed well test model to conduct an unstable well test on the target well group in the gas storage reservoir, to obtain a first well test interpretation curve plate for characterizing the effect of the water body outside the fault on the sealing of the gas storage reservoir along the injection and production cycle, a second well test interpretation curve plate for characterizing the effect of the well-to-well interference on the sealing of the gas storage reservoir along the injection and production cycle, or a third well test interpretation curve plate for characterizing the effect of the boundary morphology response on the sealing of the gas storage reservoir along the injection and production cycle.

[0042] In the present invention, the well test model mainly includes: wellbore model, well model, reservoir model and boundary model. When constructing the well test model, the parameters used mainly include: wellbore radius, perforation layer, perforation thickness, estimated skin factor, well depth, wellbore trajectory, fluid density, volume coefficient, viscosity, compression coefficient, net-to-gross ratio, porosity, rock compression coefficient, permeability, estimated boundary distance, boundary type, initial formation pressure, etc. Among them, the construction method of the well test model belongs to the method well known in the art, so it will not be repeated here.

[0043] After a single unstable well test is conducted on the target well group in the gas storage using the pre-built well test model, Figure 2 As shown, a normalized pressure curve 21 and a normalized pressure derivative curve 22 may be generated based on the data obtained during the well testing process (including normalized pressure data and normalized pressure integral derivative data, etc.).

[0044] The unstable well testing process mainly includes: analyzing the wellbore storage effect, surface change analysis, reservoir parameter change analysis, water conduction analysis outside the fault, well-to-well interference analysis and boundary morphological response analysis of the target well group near the wellbore of the gas storage reservoir.

[0045] Unstable well testing methods may include: pressure drop well testing, pressure recovery well testing, interference well testing, pulse well testing, etc.

[0046] like Figure 3 As shown in FIG, the flow stages obtained after the unstable well test can be divided into three stages: the early stage, the middle stage and the late stage; the early stage includes the continuous flow stage (also called the well reservoir stage), and also includes the linear flow stage, the bilinear flow stage, and sometimes the spherical flow stage; the middle stage includes the radial flow stage and the quasi-radial flow stage; the late stage includes the stable flow stage and the quasi-stable flow stage.

[0047] The curves generated after the wellbore reservoir effect analysis and the skin change analysis belong to the early stage; the curves generated after the reservoir parameter change analysis belong to the middle stage; the curves generated after the fault water body conductivity analysis, the well interference analysis and the boundary morphological response analysis belong to the late stage. The curves described here include the normalized pressure curve and the normalized pressure derivative curve.

[0048] Among them, the wellbore storage effect is mainly the storage effect when the bottomhole fluid continues to flow into the wellbore and causes the pressure to increase when the well is closed instantaneously during the high-speed injection and production process of the gas storage reservoir; when the well is opened instantaneously, the bottomhole fluid increases slowly and the wellbore fluid is produced rapidly.

[0049] The change of near-wellbore contaminated skin mainly takes into account the fact that due to mud invasion, imperfect perforation or acidizing, fracturing, or pollution or production-increasing measures during the drilling and completion process, the permeability of the annular area around the wellbore is different from that of the oil layer. When the fluid flows from the oil layer into the wellbore, an additional pressure drop effect is generated (when the fluid flows from the production layer into the wellbore, an additional pressure drop will be generated in the skin area, which represents the effectiveness of pollution or production-increasing measures in the reservoir).

[0050] The changes in reservoir physical property parameters take into account the changes in characteristic responses such as pseudo-radial flow, fracture radial flow, inner zone radial flow, and outer zone radial flow caused by reservoir physical properties.

[0051] Since the present invention mainly detects the sealing of the gas storage reservoir through the analysis of water conduction outside the fault, the analysis of well interference and the analysis of boundary morphological response, the present invention focuses on the expression of the regularized pressure curve and the regularized pressure derivative curve in the late stage.

[0052] It should be noted that in order to improve the reliability of sealing detection, the present invention can carry out multiple unstable well tests in the same injection and production round of the target well group, or carry out unstable well tests in different injection and production rounds, thereby obtaining multiple regularized pressure curves and multiple regularized pressure derivative curves, and then graphically superimpose the multiple regularized pressure curves and multiple regularized pressure derivative curves in double logarithmic coordinates to obtain the corresponding well test interpretation curve plate.

[0053] Among them, the curve charts include: the first well test interpretation curve chart used to characterize the influence of water outside the fault on the sealing of the gas storage reservoir along the injection and production cycle, the second well test interpretation curve chart used to characterize the influence of inter-well interference on the sealing of the gas storage reservoir along the injection and production cycle, and the third well test interpretation curve chart used to characterize the influence of boundary morphology response on the sealing of the gas storage reservoir along the injection and production cycle.

[0054] The above three well test interpretation curves are independent, and each well test interpretation curve can independently detect the sealing effect of the gas storage. Among them, the water conduction outside the fault and the boundary morphological response represent two different stages of the gas storage. If the fault is damaged but not fully connected, the fault is equivalent to the reservoir boundary, and the boundary cracks will affect the sealing of the gas storage. At this time, there will be a fault reaction, and the third well test interpretation curve is generated. If the fault is in a connected state, the water outside the fault will affect the sealing of the gas storage. At this time, there will be a water body reaction, and the first well test interpretation curve is generated.

[0055] In order to further improve the reliability of detection, the first well test interpretation curve plate can be combined with the second well test interpretation curve plate for detection, and the third well test interpretation curve plate can also be combined with the second well test interpretation curve plate for detection.

[0056] For example, the first well test interpretation curve plate can be combined with the second well test interpretation curve plate for detection. For example, if the fault is in a connected state, the first well test interpretation curve plate is generated, and the gas storage reservoir sealing effect is detected to be qualified from the first well test interpretation curve plate; the second well test interpretation curve plate can be further used for detection. If the gas storage reservoir sealing effect is detected to be unqualified from the second well test interpretation curve, it is determined that the gas storage reservoir sealing effect is unqualified. However, generally speaking, the gas storage reservoir sealing effect detected from the first well test interpretation curve plate is consistent with the gas storage reservoir sealing effect detected from the second well test interpretation curve plate.

[0057] Specifically, for the first well test interpretation curve chart, the pre-built well test model can be used to conduct pressure recovery well tests or pressure drop well tests on the target well group in the gas storage reservoir in different rounds, or multiple pressure recovery well tests or pressure drop well tests can be conducted in the same round. At the end of each well test, a first normalized pressure curve and a first normalized pressure derivative curve are generated;

[0058] The first normalized pressure curves obtained from multiple unstable well tests are superimposed in a double logarithmic coordinate system, and the first normalized pressure derivative curves are superimposed in the double logarithmic coordinate system to obtain a first well test interpretation curve chart.

[0059] Similarly, for the second well test interpretation curve plate, the pre-built well test model is used to conduct multiple rounds of interference well tests or pulse well tests on the target well group in the gas storage reservoir to obtain the pressure data of the observation well;

[0060] At the end of each well test, a corresponding pressure curve is generated according to the pressure data of the observation well;

[0061] The pressure curves obtained from multiple well tests are superimposed in the coordinate system to obtain the second well test interpretation curve chart.

[0062] The interference well test specifically includes the following steps:

[0063] 1) According to the geological characteristics of the gas storage area, such as Figure 4 As shown, a test well group is selected including an excitation well and one or several adjacent observation wells; when the excitation well is located in the gas storage area, the observation well is located outside the test area; when the excitation well is located outside the gas storage area, the observation well is located in the test area.

[0064] 2) By changing the working system of the exciting well, the pressure in the formation changes, and the pressure data in the well is recorded using a high-precision and high-sensitivity pressure gauge;

[0065] 3) Generate pressure curves based on recorded pressure data to determine the connectivity of reservoirs between wells.

[0066] Among them, the pressure curve generated by the interference well test can be shown as Figure 5 shown.

[0067] The pulse well test specifically includes the following steps:

[0068] 1) According to the geological characteristics of the gas storage area, such as Figure 4 As shown, a test well group is selected including an excitation well and one or several adjacent observation wells; when the excitation well is located in the gas storage area, the observation well is located outside the test area; when the excitation well is located outside the gas storage area, the observation well is located in the test area.

[0069] 2) In the excitation well (pulse well), the well is opened and closed periodically to form a pulse signal. In the observation well, the pulse pressure data is measured with a high-sensitivity instrument.

[0070] 3) Generate a pressure curve based on the recorded pressure data to determine the reservoir connectivity between wells.

[0071] According to the third well test interpretation curve chart, a pre-built well test model is used to conduct multiple unstable well tests on the target wells in the gas storage reservoir in the same round; or unstable well tests are conducted on the target wells in different rounds;

[0072] At the end of each unstable well test, a second normalized pressure curve and a second normalized pressure derivative curve are generated;

[0073] A plurality of second normalized pressure curves obtained from multiple unstable well tests are superimposed in a double logarithmic coordinate system, and a plurality of second normalized pressure derivative curves are superimposed in a double logarithmic coordinate system to obtain a third well test interpretation curve plate.

[0074] S111, testing the sealing performance of the gas storage reservoir according to the first well test interpretation curve plate, the second well test interpretation curve plate or the third well test interpretation curve plate to obtain a test result of the sealing performance of the gas storage reservoir.

[0075] In one embodiment, the first well test interpretation curve chart includes first normalized pressure curves corresponding to multiple rounds and first normalized pressure derivative curves corresponding to multiple rounds; the sealing of the gas storage reservoir is tested according to the first well test interpretation curve chart to obtain a first test result, including:

[0076] As the number of rounds increases, if the inflection point where the first regularized pressure curve turns to a horizontal line decreases in height, and the arrival time of the downward inflection point of the first regularized pressure derivative curve is advanced, it is determined that the first test result is that the gas storage reservoir is unqualified in sealing.

[0077] Specifically, when the fault seal fails, with the fluctuation of periodic injection and production pressure, the water outside the fault gradually invades the near-well area. Through the unstable well test of the target well, at this moment, the "late stage" in the first well test interpretation curve chart presents the "stable flow" characteristics of the equivalent constant pressure boundary, and the pressure distribution of the reservoir remains constant (pressure does not change with time), and the pressure at each point in the reservoir remains constant. Figure 6 As shown, in the double logarithmic curve, the constant pressure stable flow in the ①②③ cycles is manifested as the first normalized pressure curve being a horizontal line, while the first normalized pressure derivative curve is a curve falling downward (approaching 0).

[0078] Theoretically, when the upper limit pressure of the gas storage reservoir is reached, as the injection and production cycle increases, the impact on the sealing becomes greater and the energy conduction of the water outside the fault becomes more obvious. Figure 6, which is reflected in the double logarithmic comprehensive graph as follows: with the increase of rounds, the height of the horizontal line at the end of the first regularized pressure curve gradually decreases (the height of the inflection point where the first regularized pressure curve turns to the horizontal line gradually decreases, which also means that the dimensionless pressure gradually decreases with the increase of rounds), and the inflection point where the end of the first regularized pressure curve turns to the horizontal line moves to the left; with the increase of rounds, the downward inflection point at the end of the first regularized pressure derivative curve will arrive earlier (approaching 0), and the downward trend will be more obvious.

[0079] That is, as the number of rounds increases, if the inflection point where the first regularized pressure curve turns to a horizontal line decreases in height, and the arrival time of the downward inflection point of the first regularized pressure derivative curve is advanced, it is determined that the first test result is that the gas storage reservoir is unqualified in sealing.

[0080] exist Figure 6 In the figure, A1 is the inflection point of the first normalized pressure curve in round ①, B1 is the inflection point of the first normalized pressure curve in round ②, and C1 is the inflection point of the first normalized pressure curve in round ③. It can be seen that the height of position C1 is the lowest, the height of position B1 is in the middle, and the height of position A1 is the highest; the horizontal line position of the end of the first normalized pressure curve in round ① is the highest, and the horizontal line position of the end of the first normalized pressure curve in round ③ is the lowest. That is, the dimensionless pressure gradually decreases with the increase of rounds.

[0081] A2 is the downward inflection point of the first normalized pressure derivative curve in round ①, B2 is the downward inflection point of the first normalized pressure derivative curve in round ②, and C2 is the downward inflection point of the first normalized pressure derivative curve in round ③. It can be seen that A2 is farthest to the right and C2 is farthest to the left, indicating that the downward inflection point of the first normalized pressure derivative curve in round ① arrives the latest, and the downward inflection point of the first normalized pressure derivative curve in round ② arrives earlier than the downward inflection point of the first normalized pressure derivative curve in round ①.

[0082] In another embodiment, the second well test interpretation curve chart includes pressure curves corresponding to multiple rounds; the sealing performance of the gas storage reservoir is tested according to the second well test interpretation curve chart to obtain a second test result, including:

[0083] In each round, when the well is shut down or the production is reduced, if the pressure curve shows an upward trend or the downward trend of the pressure curve slows down, the second test result is determined to be that the gas storage reservoir is unqualified for sealing;

[0084] In each round, when the well is stimulated to be opened or the production is increased, if the pressure curve shows a downward trend or the upward trend of the pressure curve slows down, it is determined that the second test result is that the sealing of the gas storage reservoir is unqualified.

[0085] Specifically, in each round, after the excited well is shut down or the production is reduced, it is determined that the pressure curve shows a clear upward trend (the pressure value increases by at least 2%), and the second test result is determined to be that the sealing of the gas storage reservoir is unqualified; or before the excited well is shut down or the production is reduced, the pressure curve shows a clear downward trend, but after the excited well is shut down or the production is reduced, the pressure curve still decreases, but the downward trend slows down, and this also indicates that the second test result is that the sealing of the gas storage reservoir is unqualified.

[0086] Similarly, in each round, when the exciting well is shut down or the production is increased, it is determined that the pressure curve shows a clear downward trend. At this time, the second test result is determined to be that the sealing of the gas storage reservoir is unqualified; or before the exciting well is opened or the production is increased, the pressure curve shows a clear upward trend, but after the exciting well is opened or the production is increased, the pressure curve still rises, but the upward trend slows down. At this time, it also indicates that the second test result is that the sealing of the gas storage reservoir is unqualified.

[0087] In another embodiment, the third well test interpretation curve chart includes a third normalized pressure curve corresponding to multiple rounds and a third normalized pressure derivative curve corresponding to multiple rounds; the sealing of the gas storage reservoir is tested according to the third well test interpretation curve chart to obtain a third test result, including:

[0088] As the number of rounds increases, if the time of reaching the inflection point of the 0.5 horizontal line in the third regularized pressure derivative curve is delayed and the height of the end horizontal line of the third regularized pressure derivative curve rises (dimensionless pressure increase), then the third test result is determined to be that the sealing of the gas storage reservoir is unqualified.

[0089] Specifically, when there is an impermeable fault boundary near the test well, through the unstable well test of the target well, the "late stage" of the third well test interpretation curve at this moment presents the "quasi-stable flow" characteristics of the equivalent impermeable boundary, and the pressure change rate of each point in the reservoir with time is the same, that is, the pressure at each point decreases at the same speed, that is, dp / dt = C (constant). When there is an impermeable fault boundary near the test well, such as Figure 7 As mentioned above, in round ①, the late stage pressure derivative curve in the third well test interpretation curve showed an increase from the "0.5 horizontal line" to the "1.0 horizontal line", and the pressure derivative doubled. Among them, dp is the change in formation pressure, and dt is the change in time.

[0090] As the number of rounds increases, when the gas storage pressure approaches or exceeds the upper limit pressure of the reservoir after multiple rounds of high-speed injection and production, the near-wellbore area and the impermeable boundary will gradually lose stability, resulting in cracks in the impermeable boundary and even destruction. Figure 7It can be seen that in the "late stage" of the third test well interpretation curve, the pressure derivative curve rises from the "0.5 horizontal line" to greater than the "1.0 horizontal line". For example, in round ②, the pressure derivative curve rises from the "0.5 horizontal line" to greater than the "1.0 horizontal line" and reaches the "1.1 horizontal line".

[0091] Theoretically, when the upper limit pressure of the gas storage reservoir is reached, as the injection and production cycle increases, the impact on the sealing of the gas storage reservoir becomes greater, and the instability of the impermeable boundary becomes more and more obvious. Figure 7 , which is reflected on the double logarithmic comprehensive chart as follows: with the increase of rounds, the height of the horizontal line at the end of the second normalized pressure derivative curve gradually rises, and the inflection point of the "0.5 horizontal line" moves to the right; among them, the inflection point of the "0.5 horizontal line" can be understood as the inflection point from the 0.5 horizontal line to a higher-order horizontal line, and the higher-order horizontal lines include the 1.0 horizontal line, the 1.1 horizontal line, the 1.2 horizontal line, and so on.

[0092] For example, refer to Figure 7 , the turning point of the '0.5 horizontal line' of round ① is A3, and the turning point of the '0.5 horizontal line' of round ② is B3. B3 is further to the right than A3, that is, B3 arrives later than A3. And the "0.5 horizontal line" of round ① rises to the "1.0 horizontal line", and the "0.5 horizontal line" of round ② rises to the "1.1 horizontal line". The height of the horizontal line at the end of round ② is higher than the height of the horizontal line at the end of round ①, which also means that the dimensionless pressure of round ② is greater than the dimensionless pressure of round ①.

[0093] In addition, the sealing effect of the gas storage reservoir can also be judged from the morphological characteristics of the pressure derivative curve. If the superposition graph of the pressure derivative curves of each round presents a "cross-step shape" as a whole, and when the "cross-step shape" gradually rises to a certain height, the tail end of the derivative curve turns into a downward trend (not shown in the figure), it can also be judged that a leak has occurred in the closed boundary.

[0094] In one embodiment, after testing the sealing performance of the gas storage reservoir according to the third well test interpretation curve plate and obtaining the third test result, the method further includes:

[0095] Determine the reservoir exploration radius for each round;

[0096] If it is determined that the corresponding reservoir detection radius shows an increasing trend with the increase in rounds, then the third test result is determined to be that the gas storage reservoir sealing is unqualified.

[0097] In one embodiment, determining the reservoir detection radius of each round includes:

[0098] According to the formula Determine the reservoir detection radius L d ;in,

[0099] k is the formation permeability, t is the pressure transmission time, φ is the reservoir porosity, μ is the fluid viscosity, C t is the comprehensive compression factor.

[0100] Specifically, in order to improve the detection accuracy of the sealing of the gas storage reservoir, it is necessary to further determine the reservoir detection radius of each round. As the rounds increase, if the reservoir detection radius is determined to gradually increase, the gas storage reservoir sealing detection result is determined to be unqualified.

[0101] In this embodiment, since the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate are all generated based on unstable well tests during the high-speed injection and production stage of the gas storage reservoir, the change rules of the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate can truly restore the geological environment in which the gas storage reservoir is located. Therefore, when the sealing of the gas storage reservoir is detected based on the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate, the influence of water conduction outside the fault, interference from adjacent wells and boundary morphological response on the sealing of the gas storage reservoir can be finely interpreted from multiple angles, thereby accurately detecting whether the sealing of the gas storage reservoir meets the requirements and ensuring the safe operation of the gas storage reservoir.

[0102] Based on the same inventive concept as in the above-mentioned embodiment, this embodiment also provides a gas storage reservoir sealing detection device, such as Figure 8 As shown, the device comprises:

[0103] The well testing unit 81 is used to perform unstable well testing on the target well group in the gas storage reservoir using a pre-built well testing model, and obtain a first well testing interpretation curve plate for characterizing the influence of the water body outside the fault on the sealing of the gas storage reservoir along with the injection and production cycle, a second well testing interpretation curve plate for characterizing the influence of the well interference on the sealing of the gas storage reservoir along with the injection and production cycle, or a third well testing interpretation curve plate for characterizing the influence of the boundary morphology response on the sealing of the gas storage reservoir along with the injection and production cycle;

[0104] The detection unit 82 is used to detect the sealing performance of the gas storage reservoir according to the first well test interpretation curve chart, the second well test interpretation curve chart or the third well test interpretation curve chart to obtain a gas storage reservoir sealing performance detection result.

[0105] In one embodiment, the first well test interpretation curve chart includes first normalized pressure curves corresponding to multiple rounds and first normalized pressure derivative curves corresponding to multiple rounds; the detection unit is specifically used for:

[0106] As the number of rounds increases, if it is determined that the inflection point of the end of the first regularized pressure curve turning into a horizontal line moves to the left, and it is determined that the inflection point of the end of the first regularized pressure derivative curve drops and moves to the left, then the first test result is determined to be that the sealing of the gas storage reservoir is unqualified.

[0107] Since the device introduced in the embodiment of the present invention is a device used to implement the gas storage reservoir sealing detection method of the embodiment of the present invention, based on the method introduced in the embodiment of the present invention, the person skilled in the art can understand the specific structure and deformation of the device, so it is not repeated here. All devices used in the method of the embodiment of the present invention belong to the scope of protection of the present invention.

[0108] Based on the same inventive concept, this embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any step of the method described above when executing the computer program.

[0109] Based on the same inventive concept, this embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the methods described above are implemented.

[0110] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0111] The present invention provides a gas storage reservoir sealing detection method, device, medium and equipment. The method comprises: using a pre-constructed well test model to perform an unstable well test on a target well group in the gas storage reservoir, obtaining a first well test interpretation curve plate for characterizing the influence of water outside the fault on the sealing of the gas storage reservoir along with the injection and production cycle, a second well test interpretation curve plate for characterizing the influence of well-to-well interference on the sealing of the gas storage reservoir along with the injection and production cycle, and a third well test interpretation curve plate for characterizing the influence of boundary morphological response on the sealing of the gas storage reservoir along with the injection and production cycle; testing the sealing of the gas storage reservoir according to the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate, and obtaining a gas storage reservoir sealing detection curve plate. Results: In this way, since the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate are all generated according to the unstable well test during the high-speed injection and production stage of the gas storage, the change rules of the first well test interpretation curve plate, the second well test interpretation curve plate and the third well test interpretation curve plate can truly restore the geological environment in which the gas storage is located. Therefore, when the sealing of the gas storage is detected based on the first well test interpretation curve plate, the second well test interpretation curve plate or the third well test interpretation curve plate, the influence of water conduction outside the fault, interference from adjacent wells and boundary morphological response on the sealing of the gas storage can be precisely interpreted, so as to accurately detect whether the sealing of the gas storage meets the requirements and ensure the safe operation of the gas storage.

[0112] Embodiment 1

[0113] In practical applications, based on the gas storage reservoir sealing detection method and device provided above, when the sealing of a gas storage reservoir is detected, the following is implemented:

[0114] The gas storage studied in this example is rebuilt from a depleted gas reservoir, with a burial depth of 1190-1340m. The well logging interpretation shows that the porosity is 27% and the permeability is 238mD, which is a high-porosity and medium-permeability reservoir. The gas reservoir has a gas-bearing area of ​​1.05km 2 The geological reserves of natural gas are 532 million cubic meters, the average thickness of the gas layer is 18.13m, and the vertical superposition and continuous distribution, the thickness of the structural high part reaches more than 35m, and it becomes thinner towards the edge. The distribution of the gas layer is controlled by both structure and lithology, which is a lithological-structural gas reservoir. The water layer is developed in the structural low part, and the gas-water interface is -1263m, which is a marginal bottom water gas reservoir. A large set of mudstone caprocks are developed in the whole area above the target layer of the gas reservoir, which is a stable medium-deep water environment deposition. The thickness of mudstone encountered by a single well is 70-220m. There are 6 normal faults in the gas reservoir in the northeast and east-west directions, and the four boundary faults F1-F4 play a decisive role in the overall construction of the reservoir. The design operating pressure of the gas storage rebuilt from this is 5-12.3MPa, the storage capacity is 525 million cubic meters, the working gas volume is 340 million cubic meters, and the number of injection and production wells is 10.

[0115] The target well is a gas injection and production well in the gas storage reservoir under study. The purpose of the well test is to obtain the pollution and permeability changes in the near-well area through pressure recovery logging, and to study the formation flow coefficient, detection radius, boundary characteristic response and inter-well interference.

[0116] According to the geological development characteristics of the gas storage reservoir, the test requirements of the target well are determined. This monitoring is carried out using a wellhead electronic pressure gauge, which has the advantages of large storage capacity, high accuracy and remote data transmission to avoid potential safety hazards of conventional well testing processes; it is required to use high-resolution (0.02Psi) and high-precision (no more than 0.05%) wellhead electronic pressure gauges during the test. The test work system for this test is that the pressure recovery test site can analyze whether the stable conditions are reached based on the data recorded by the pressure gauge. If the stable conditions are not reached, the test time will be extended until the wellhead pressure is stable; the stable condition for production is that the daily change does not exceed 2%, and the stable pressure condition is that the daily change does not exceed 5Psi. According to the current wellhead pressure, a pressure gauge with a pressure range of 5000Psi is selected, and equipment inspection work is carried out before construction to ensure smooth monitoring construction.

[0117] In the specific test process, first install the pressure gauge and record the flow pressure data under the current production; then shut down the wellhead and conduct a pressure recovery test; then start production; finally, turn off the power to the pressure gauge to complete the well test.

[0118] After one round, the production records and pressure test data are used for fine well test interpretation to obtain the corresponding well test interpretation curve ( Figure 2 A total of 4 rounds were carried out to obtain the corresponding well test interpretation curve chart (see Figure 7 ).

[0119] After 4 rounds, the well test interpretation results are shown in Table 1 (mainly some well logging parameters), which include the changes of the detection radius Lb (Lb1~Lb4) in different rounds. It should be noted that after the unstable well test, in addition to the corresponding well test interpretation curve, the well test interpretation results shown in Table 1 can also be obtained.

[0120] Table 1

[0121] Formation pressure 12.95 MPa Formation permeability 195.6md Formation coefficient 5250md.m Detection radius Lb1 125.1m Vertical / diameter permeability ratio 0.08 Detection radius Lb2 131.2m Well storage coefficient <![CDATA[1.33m 3 / MPa]]> Detection radius Lb3 135.6m Well epidermis 1.11 Detection radius Lb4 136.4m

[0122] Figure 7 In the figure, as the number of rounds increases, the horizontal line at the end of the second normalized pressure derivative curve gradually rises, and the turning point of the '0.5 horizontal line' moves to the right, indicating that the sealing of the gas storage reservoir is unqualified. It can be seen from Table 1 that the four detection radius values ​​gradually increase, and the change trend is obvious. It can also be judged that the sealing of the gas storage reservoir is gradually deteriorating. Although the preferred embodiments of the present invention have been described, once those skilled in the art know the basic creative concepts, they can make additional changes and modifications to these embodiments. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the sealing performance of a gas storage reservoir, characterized in that: The method comprises: Using the pre-built well test model, an unstable well test is performed on the target well group in the gas storage reservoir, and a first well test interpretation curve plate for characterizing the influence of the water body outside the fault on the sealing of the gas storage reservoir with the injection and production cycle, a second well test interpretation curve plate for characterizing the influence of the well-to-well interference on the sealing of the gas storage reservoir with the injection and production cycle, or a third well test interpretation curve plate for characterizing the influence of the boundary morphology response on the sealing of the gas storage reservoir with the injection and production cycle is obtained; The sealing performance of the gas storage reservoir is tested according to the first well test interpretation curve plate, the second well test interpretation curve plate or the third well test interpretation curve plate to obtain a gas storage reservoir sealing performance test result.

2. The method according to claim 1, characterized in that The first well test interpretation curve chart includes a first normalized pressure curve corresponding to multiple rounds and a first normalized pressure derivative curve corresponding to multiple rounds; the gas storage reservoir sealing is tested according to the first well test interpretation curve chart to obtain a first test result, including: As the number of rounds increases, if the inflection point where the first regularized pressure curve turns to a horizontal line decreases in height, and the arrival time of the downward inflection point of the first regularized pressure derivative curve is advanced, it is determined that the first detection result is that the gas storage reservoir is unqualified in sealing.

3. The method according to claim 1, characterized in that The second well test interpretation curve chart includes pressure curves corresponding to multiple rounds; the gas storage reservoir sealing is tested according to the second well test interpretation curve chart to obtain a second test result, including: In each round, when the well is shut down or the production is reduced, if the pressure curve shows an upward trend or the downward trend of the pressure curve slows down, it is determined that the second test result is that the gas storage reservoir is unqualified in sealing; In each round, when the well is stimulated to be opened or the production is increased, if the pressure curve shows a downward trend or the upward trend of the pressure curve slows down, it is determined that the second test result is that the sealing of the gas storage reservoir is unqualified.

4. The method according to claim 1, characterized in that The third well test interpretation curve chart includes a third normalized pressure curve corresponding to multiple rounds and a third normalized pressure derivative curve corresponding to multiple rounds; the third test result is obtained by testing the sealing performance of the gas storage according to the third well test interpretation curve chart, including: As the rounds increase, if the arrival time of the 0.5 horizontal line inflection point in the third normalized pressure derivative curve is delayed and the end horizontal line height of the third normalized pressure derivative curve rises, it is determined that the third test result is that the gas storage reservoir sealing is unqualified.

5. The method according to claim 1, characterized in that After testing the sealing performance of the gas storage reservoir according to the third well test interpretation curve plate and obtaining the third test result, the method further comprises: Determine the reservoir exploration radius for each round; If it is determined that the corresponding reservoir detection radius shows an increasing trend with the increase in rounds, then the third detection result is determined to be that the sealing of the gas storage reservoir is unqualified.

6. The method according to claim 5, characterized in that Determining the reservoir detection radius of each round includes: According to the formula Determine the reservoir detection radius L d ;in, k is the formation permeability, t is the pressure transmission time, φ is the reservoir porosity, μ is the fluid viscosity, and C t is the comprehensive compression factor.

7. A gas storage reservoir sealing detection device, characterized in that: The device comprises: A well testing unit is used to perform unstable well testing on a target well group in a gas storage reservoir using a pre-built well testing model, and obtain a first well testing interpretation curve plate for characterizing the influence of water outside the fault on the sealing of the gas storage reservoir along with the injection and production cycle, a second well testing interpretation curve plate for characterizing the influence of well-to-well interference on the sealing of the gas storage reservoir along with the injection and production cycle, or a third well testing interpretation curve plate for characterizing the influence of boundary morphological response on the sealing of the gas storage reservoir along with the injection and production cycle; The detection unit is used to detect the sealing performance of the gas storage reservoir according to the first well test interpretation curve chart, the second well test interpretation curve chart or the third well test interpretation curve chart to obtain the sealing performance detection result of the gas storage reservoir.

8. The device according to claim 7, characterized in that The first well test interpretation curve chart includes a first normalized pressure curve corresponding to multiple rounds and a first normalized pressure derivative curve corresponding to multiple rounds; the detection unit is specifically used for: As the number of rounds increases, if it is determined that the inflection point of the end of the first regularized pressure curve turning into a horizontal line moves to the left, and it is determined that the inflection point of the end of the first regularized pressure derivative curve drops and moves to the left, then the first test result is determined to be that the sealing of the gas storage reservoir is unqualified.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. 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 program, the steps of the method according to any one of claims 1 to 6 are implemented.

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