Method and device for determining working gas volume of underground gas storage

Abstract

The present invention provides a method and device for determining the working gas volume of an underground gas storage reservoir. The method includes: splitting the underground gas storage reservoir into multiple gas storage units centered on the gas production wells; calculating the controlled formation range of the gas production wells according to the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage reservoir, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage reservoir, to obtain the formation radius controlled by each gas production well in each gas storage unit; determining the increased working gas volume of the underground gas storage reservoir according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir. By taking the gas storage unit as a unit and independently determining the formation radius controlled by each gas production well, the increased working gas volume of the underground gas storage reservoir is obtained. Compared with the prior art, there is no need to solve the problem of pressure imbalance, the data measurement is accurate, and the increased gas storage volume of the working gas volume of the underground gas storage reservoir due to the reduction of the lower limit pressure is accurately determined.

Description

Technical Field

[0001] The present invention relates to the technical field of underground natural gas storage and reserve utilization, and particularly to a method and device for determining the working gas volume of an underground gas storage. Background Art

[0002] At present, the actual working gas volume of the underground gas storage in operation is much lower than the designed working gas volume. In order to further increase the working gas volume, the lower limit pressure of the underground gas storage can be reduced. However, how to accurately determine the increased gas volume range due to the reduction of the lower limit pressure of the existing gas storage is a technical problem that puzzles those skilled in the art.

[0003] The current calculation method for increasing the working gas volume of existing gas storage is based on the traditional overall pressure drop method of the gas reservoir. The basic idea is to consider the entire gas storage formation as an overall pressure drop. This overall pressure drop method requires the value after the whole field pressure balance as the calculation basis. However, in the existing and operating gas storage, the pressure field is often difficult to be truly balanced. Because the gas storage injects and produces gas reciprocally through numerous production wells, the bottom hole pressure is lower than the surrounding pressure during gas production, forming a pressure drop funnel. Moreover, the balance period of the injection-production conversion is extremely short, and the pressure drop funnel cannot fully expand to the boundary of the gas storage formation, resulting in the pressure imbalance phenomenon of low bottom hole pressure and high surrounding pressure. At this time, it is difficult to obtain the average reservoir pressure.

[0004] It can be seen that the current method for determining the working gas volume of the underground gas storage regards the gas storage formation as an overall pressure drop, and then requires the pressure data after the complete balance of the gas reservoir formation pressure field. However, the on-site cyclic gas injection and production cannot achieve the pressure field balance, resulting in difficulties in accurately obtaining the pressure value, and thus it is difficult to accurately determine the increased gas storage volume of the underground gas storage due to the reduction of the lower limit pressure. Summary of the Invention

[0005] An embodiment of the present invention provides a method for determining the working gas volume of an underground gas storage, which is used to accurately determine the increased gas storage volume of the underground gas storage due to the reduction of the lower limit pressure. The method includes:

[0006] Splitting the underground gas storage into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on one gas production well;

[0007] Calculating the controlled formation range of the gas production well according to the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, and obtaining the formation radius controlled by each gas production well in each gas storage unit;

[0008] Determining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage.

[0009] In a specific embodiment, according to the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operating parameters of the underground gas storage reservoir, and the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage reservoir, calculate the controlled gas storage formation range of the gas production well, and obtain the formation radius controlled by each gas production well in each gas storage unit, including:

[0010] According to the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operating parameters of the underground gas storage reservoir, and the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage reservoir, through the calculation formula for the controlled gas storage formation range of the gas production well, obtain the formation radius controlled by each gas production well in each gas storage unit; wherein, the calculation formula for the controlled gas storage formation range of the gas production well is used to characterize the supply range of the gas production well to the gas storage formation.

[0011] The above calculation formula for the controlled gas storage formation range of the gas production well is:

[0012]

[0013] wherein, R eout represents the formation radius controlled by each gas production well;

[0014] P Pmin represents the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage reservoir;

[0015] P Pwfout represents the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well;

[0016] P min represents the target lower limit pressure of the underground gas storage reservoir;

[0017] P max represents the upper limit pressure of the underground gas storage reservoir;

[0018] B g represents the volume coefficient of the gas in the underground gas storage reservoir;

[0019] P sc represents the pressure under standard conditions;

[0020] T sc represents the temperature under standard conditions;

[0021] T represents the formation temperature of the underground gas storage reservoir;

[0022] η represents the pressure conductivity coefficient of the underground gas storage reservoir formation;

[0023] t out represents the gas production time of each gas production well;

[0024] r w represents the wellbore radius of each gas production well;

[0025] e represents the natural constant, with a value of 2.71828.

[0026] In specific implementation, according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, the increased working gas volume of the underground gas storage reservoir is determined, including:

[0027] According to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, using the traditional material balance equation, determine the increased working gas volume of each gas storage unit;

[0028] Accumulate the increased working gas volume of each gas storage unit to obtain the increased working gas volume of the underground gas storage reservoir.

[0029] The traditional material balance equation is:

[0030]

[0031] Wherein, G represents the increased working gas volume of each gas storage unit;

[0032] represents the formation porosity of each gas production well;

[0033] c t represents the compressibility of the formation rock of each gas production well;

[0034] h represents the formation thickness of each gas production well;

[0035] B g represents the volume factor of the gas in the underground gas storage reservoir;

[0036] P min represents the target lower limit pressure of the underground gas storage reservoir;

[0037] P max represents the upper limit pressure of the underground gas storage reservoir;

[0038] R eout represents the formation radius controlled by each gas production well.

[0039] The embodiment of the present invention also provides an underground gas storage reservoir working gas volume determination device for accurately determining the increased gas storage volume of the working gas volume of the underground gas storage reservoir due to the reduction of the lower limit pressure. The device includes:

[0040] A gas storage reservoir splitting module for splitting the underground gas storage reservoir into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on a gas production well;

[0041] A controlled formation radius determination module, configured to calculate the controlled gas storage formation range of a gas production well according to the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the underground gas storage operation parameters, and the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage, so as to obtain the formation radius controlled by each gas production well in each gas storage unit;

[0042] A working gas volume increase determination module, configured to determine the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage.

[0043] In a specific embodiment, the controlled formation radius determination module is specifically configured to:

[0044] According to the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the underground gas storage operation parameters, and the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage, through the calculation formula for the controlled gas storage formation range of the gas production well, obtain the formation radius controlled by each gas production well in each gas storage unit; wherein, the calculation formula for the controlled gas storage formation range of the gas production well is used to represent the supply range of the gas production well to the gas storage formation;

[0045] The calculation formula for the controlled gas storage formation range of the gas production well is:

[0046]

[0047] Wherein, R eout represents the formation radius controlled by each gas production well;

[0048] P Pmin represents the pseudopressure value corresponding to the target lower limit pressure of the underground gas storage;

[0049] P Pwfout represents the pseudopressure value corresponding to the bottom-hole pressure resistance value of each gas production well;

[0050] P min represents the target lower limit pressure of the underground gas storage;

[0051] P max represents the upper limit pressure of the underground gas storage;

[0052] B g represents the volume coefficient of the gas in the underground gas storage;

[0053] P sc represents the pressure under standard conditions;

[0054] T sc represents the temperature under standard conditions;

[0055] T represents the formation temperature of the underground gas storage;

[0056] η represents the pressure conductivity coefficient of the formation of the underground gas storage reservoir;

[0057] t out represents the gas production time of each gas production well;

[0058] r w represents the wellbore radius of each gas production well;

[0059] e represents the natural constant, with a value of 2.71828.

[0060] In specific implementation, the working gas volume increase determination module is specifically configured to:

[0061] According to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, use the traditional material balance equation to determine the increased working gas volume of each gas storage unit;

[0062] Accumulate the increased working gas volumes of each gas storage unit to obtain the increased working gas volume of the underground gas storage reservoir.

[0063] The traditional material balance equation is:

[0064]

[0065] Among them, G represents the increased working gas volume of each gas storage unit;

[0066] represents the formation porosity of each gas production well;

[0067] c t represents the compressibility coefficient of the formation rock of each gas production well;

[0068] h represents the formation thickness of each gas production well;

[0069] B g represents the volume coefficient of the gas in the underground gas storage reservoir;

[0070] P min represents the target lower limit pressure of the underground gas storage reservoir;

[0071] P max represents the upper limit pressure of the underground gas storage reservoir;

[0072] R eout represents the formation radius controlled by each gas production well.

[0073] An embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for determining the working gas volume of the underground gas storage reservoir is implemented.

[0074] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program for executing the method for determining the working gas volume of the underground gas storage

[0075] In an embodiment of the present invention, the underground gas storage is split into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on one gas production well; according to the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, calculate the formation range controlled by the gas production well to obtain the formation radius controlled by each gas production well in each gas storage unit; according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage, determine the increased working gas volume of the underground gas storage. By splitting the underground gas storage into multiple gas storage units centered on the gas production wells, taking one gas storage unit as a unit, independently determining the formation radius controlled by each gas production well, and obtaining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well. Compared with the prior art that uses the entire reservoir of the underground gas storage as the calculation unit, it is possible to determine the increased working gas volume of the underground gas storage without solving the problem of pressure imbalance, the data is better obtained and the measurement is accurate, so that the increased gas storage volume of the working gas volume of the underground gas storage due to the reduction of the lower limit pressure can be accurately determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0077] Figure 1 It is a schematic diagram of the method for determining the working gas volume of the underground gas storage in the embodiment of the present invention.

[0078] Figure 2 It is a schematic diagram of the method for determining the bottom-hole pressure resistance value in a specific embodiment of the present invention.

[0079] Figure 3 It is a schematic diagram of the implementation method of step 203 in a specific embodiment of the present invention.

[0080] Figure 4 It is a schematic diagram of the implementation process of step 103 in a specific embodiment of the present invention.

[0081] Figure 5 It is a schematic diagram of the device for determining the working gas volume of the underground gas storage in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0082] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0083] An embodiment of the present invention provides a method for determining the working gas volume of an underground gas storage, which is used to accurately determine the increased gas storage volume of the working gas volume of the underground gas storage due to the reduction of the lower limit pressure. As Figure 1 shown, the method includes:

[0084] Step 101: Split the underground gas storage into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on one gas production well;

[0085] Step 102: Calculate the controlled gas storage formation range of the gas production well according to the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, and obtain the formation radius controlled by each gas production well in each gas storage unit;

[0086] Step 103: Determine the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage.

[0087] From Figure 1 the shown process, it can be known that in the embodiment of the present invention, by splitting the underground gas storage into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on one gas production well; calculating the controlled gas storage formation range of the gas production well according to the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, and obtaining the formation radius controlled by each gas production well in each gas storage unit; determining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage. By splitting the underground gas storage into multiple gas storage units centered on the gas production wells, taking one gas storage unit as a unit, independently determining the formation radius controlled by each gas production well, and obtaining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well. Compared with the prior art that takes the reservoir of the entire underground gas storage as the calculation unit, the increased working gas volume of the underground gas storage can be determined without solving the problem of pressure imbalance, the data is better obtained and the measurement is accurate, so that the increased gas storage volume of the working gas volume of the underground gas storage due to the reduction of the lower limit pressure can be accurately determined.

[0088] In specific implementation, the underground gas storage is first split into multiple gas storage units centered around the gas production wells; among them, each gas storage unit is centered around one gas production well. Since in the existing methods, taking the entire underground gas storage as a whole makes it difficult to achieve the overall pressure balance, the applicant splits the entire underground gas storage into individual gas storage units, with each gas storage unit as an independent whole, thereby avoiding the problem that the pressure field needs to be completely balanced. In specific implementation, with one gas production well as the center of one gas storage unit, the underground gas storage is split into multiple gas storage units.

[0089] After splitting to obtain multiple gas storage units, according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, calculate the gas storage formation range controlled by the gas production well to obtain the formation radius controlled by each gas production well in each gas storage unit. In specific implementation, according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, through the calculation formula for the gas storage formation range controlled by the gas production well, obtain the formation radius controlled by each gas production well in each gas storage unit.

[0090] Among them, the above calculation formula for the gas storage formation range controlled by the gas production well is used to represent the supply range of the gas production well to the gas storage formation, and the calculation formula for the gas storage formation range controlled by the gas production well is:

[0091]

[0092] Among them, R eout represents the formation radius controlled by each gas production well, m;

[0093] P Pmin represents the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, MPa 2 / (mPa.s);

[0094] P Pwfout represents the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, MPa 2 / (mPa.s);

[0095] P min represents the target lower limit pressure of the underground gas storage, MPa;

[0096] P max represents the upper limit pressure of the underground gas storage, MPa;

[0097] B g represents the volume coefficient of the gas in the underground gas storage;

[0098] P scIt represents the pressure under standard conditions, taking 0.101 325 MPa;

[0099] T sc It represents the temperature under standard conditions, taking 293 K;

[0100] T represents the formation temperature of the underground gas storage, in K;

[0101] η represents the pressure conductivity coefficient of the formation of the underground gas storage;

[0102] t out It represents the gas production time of each gas production well, in d;

[0103] r w It represents the wellbore radius of each gas production well, in m;

[0104] e represents the natural constant, with a value of 2.71828.

[0105] In specific implementation, the operating parameters of the underground gas storage such as the volume coefficient of the gas in the underground gas storage, the formation temperature of the underground gas storage, and the pressure conductivity coefficient of the formation of the underground gas storage can be measured or obtained according to analysis data, historical data, etc. The target lower limit pressure of the underground gas storage is the given expected minimum pressure that the underground gas storage can reach. After the target lower limit pressure of the underground gas storage is given, it is converted into the form of pseudo-pressure and substituted into the above formula.

[0106] In a specific embodiment, the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well is determined according to the bottom-hole pressure resistance value of each gas production well. Since it is difficult to accurately measure the bottom-hole pressure resistance value of each gas production well when the gas production well is in operation, a wellbore model of the gas production well can be constructed, and the operation of the gas production well can be simulated by using the wellbore model of the gas production well, so as to obtain the bottom-hole pressure resistance value of each gas production well. The specific implementation process is as Figure 2 shown, including:

[0107] Step 201: Simulate each gas production well to obtain the wellbore model of each gas production well;

[0108] Step 202: Simulate the formation of a pressure drop funnel during gas production in the wellbore model, increase the gas production rate in accordance with a preset amplitude, and record the gas leakage conditions of the supply edge of the gas storage layer, the bottom-hole pressure, and the three overlying permeable formations of the wellbore model;

[0109] Step 203: Determine the bottom-hole pressure resistance value of each gas production well according to the supply upper limit pressure of the gas storage layer, the bottom-hole pressure, and the gas leakage conditions of the three overlying permeable formations of the wellbore model.

[0110] In the specific implementation of step 201, first, based on the actual drilled geological stratification, clarify the configuration relationships of the three sets of permeable layers and the interlayer lithology and thickness above the gas storage layer of the underground gas storage reservoir. Secondly, make formation models respectively according to the actual drilled geological stratification results, and stack them according to the configuration relationships to form a geological model considering the gas storage layer and its overlying strata. Finally, drill holes in the model to simulate well drilling, inject corresponding cement for sealing, and simulate well cementing to form the wellbore model of the gas production well.

[0111] In the specific implementation of step 202, simulate the formation temperature and stress environment, form a pressure drawdown funnel by gas production at the bottom (gas storage layer) of the wellbore model of the gas production well, and monitor the gas leakage situation in the three sets of overlying permeable layers of the model. The gas production rate increases incrementally according to a preset amplitude, for example, increasing by 10% of the gas reservoir development rate, and record the leakage situations of the supply edge (upper limit pressure) of the gas storage layer, the bottom hole pressure, and the three sets of overlying permeable formations.

[0112] The specific implementation process of step 203 is as Figure 3 shown, including:

[0113] Step 301: Determine the pressure square difference according to the upper limit pressure of the gas supply of the gas storage layer and the bottom hole pressure of a gas production well.

[0114] Step 302: Draw the relationship curve between the gas production rate and the pressure square difference, and determine the inflection point.

[0115] Step 303: If no gas leakage is found in the three sets of overlying permeable formations of the wellbore model corresponding to the above inflection point, determine the bottom hole pressure corresponding to this inflection point as the bottom hole pressure tolerance value of this gas production well.

[0116] If no gas leakage is found in the three sets of overlying permeable formations of the wellbore model corresponding to the above inflection point, the bottom hole pressure corresponding to this inflection point is the temporary short-term bottom hole pressure tolerance value of the gas production well, and the temporary short-term bottom hole pressure tolerance value of this gas production well can be used as the bottom hole pressure tolerance value of this gas production well.

[0117] After obtaining the formation radius controlled by each gas production well in each gas storage unit, determine the increased working gas volume of the underground gas storage reservoir according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir. The specific implementation process is as Figure 4 shown, including:

[0118] Step 401: Determine the increased working gas volume of each gas storage unit according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir by using the traditional material balance equation.

[0119] Step 402: Accumulate the increased working gas volumes of each gas storage unit to obtain the increased working gas volume of the underground gas storage reservoir.

[0120] In the specific implementation of step 401, by substituting the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure value of the underground gas storage reservoir into the traditional material balance equation, the increased working gas volume of each gas storage unit can be obtained. The traditional material balance equation is as follows:

[0121]

[0122] Wherein, G represents the increased working gas volume of each gas storage unit;

[0123] represents the formation porosity of each gas production well, in decimals;

[0124] c t represents the compressibility of the formation rock of each gas production well, 1 / MPa;

[0125] h represents the formation thickness of each gas production well, m;

[0126] B g represents the volume factor of the gas in the underground gas storage reservoir;

[0127] P min represents the target lower limit pressure of the underground gas storage reservoir, MPa;

[0128] P max represents the upper limit pressure of the underground gas storage reservoir, MPa;

[0129] R eout represents the formation radius controlled by each gas production well, m.

[0130] The method for determining the working gas volume of the underground gas storage reservoir provided by the specific embodiment of the present invention has the following main advantages:

[0131] First, it divides the whole into parts. By reducing the pressure field area, the pressure imbalance problem of the existing method is greatly reduced.

[0132] Second, a mathematical formula for the formation range of the gas storage formation controlled by the gas production well is established to further eliminate the pressure imbalance problem within the control range of the gas production well.

[0133] Third, due to the elimination of the influence of traditional pressure imbalance, the pressure recovery time of the conventional balance period of the gas storage reservoir is greatly reduced, making it possible to meet the production demand of rapid injection-production conversion. Therefore, the applicable range is larger than that of the existing method.

[0134] Fourth, when determining the formation range of the gas storage formation controlled by the gas production well, not only the lower limit pressure of the underground gas storage reservoir is considered, but also the temporary pressure resistance value of the bottom hole of the gas production well is fully considered to prevent potential risks such as bottom hole air leakage and sand production. The considered factors are more comprehensive.

[0135] In a specific embodiment of the present invention, when calculating the increased scale of the working gas volume in the underground gas storage due to the reduction of the lower limit pressure, the practice of regarding the gas storage formation of the gas storage as a single pressure drop unit is completely broken. Instead, the gas storage formation is split into gas storage units centered on the gas production wells. Furthermore, the problem of pressure imbalance faced by the existing method is cleverly hidden and processed by establishing a mathematical formula for the range of the gas storage formation controlled by the gas production wells, calculating the range of the formation controlled by each gas production well, and finally obtaining the method for calculating the increased value of the working gas volume in the entire underground gas storage due to the reduction of the lower limit pressure.

[0136] Through example calculations, a certain gas storage in Tianjin has not reached the design expectation after nearly 17 years of operation. It is planned to reduce the lower limit pressure by 1 MPa to increase the working gas volume. According to the existing algorithm, this move can increase the working gas volume by 0.07 billion cubic meters. The actual operation shows that the working gas volume only increases by 0.58 billion cubic meters. The reason is that the bottom hole pressure is too low during actual gas production and forced production stops. The actual result is close to the value of 0.6 billion cubic meters calculated by the present invention, which proves that the method for determining the working gas volume of the underground gas storage provided by the present invention is relatively reliable.

[0137] Based on the same inventive concept, an embodiment of the present invention also provides an apparatus for determining the working gas volume of an underground gas storage. Since the principle of solving the problem by the apparatus for determining the working gas volume of the underground gas storage is similar to that of the method for determining the working gas volume of the underground gas storage, the implementation of the apparatus for determining the working gas volume of the underground gas storage can refer to the implementation of the method, and the repeated parts will not be elaborated. The specific structure is as Figure 5 shown:

[0138] The gas storage splitting module 501 is used to split the underground gas storage into multiple gas storage units centered on the gas production wells; wherein, each gas storage unit is centered on a gas production well.

[0139] The controlled formation radius determination module 502 is used to calculate the range of the gas storage formation controlled by the gas production well according to the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, and obtain the formation radius controlled by each gas production well in each gas storage unit.

[0140] The working gas volume increase determination module 503 is used to determine the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage.

[0141] In a specific embodiment, the controlled formation radius determination module 502 is specifically used for:

[0142] According to the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, the operation parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, through the calculation formula for the range of the gas storage formation controlled by the gas production well, obtain the formation radius controlled by each gas production well in each gas storage unit.

[0143] Among them, the calculation formula for the range of the gas production well controlling the gas storage formation is used to characterize the supply range of the gas production well to the gas storage formation, and is expressed as:

[0144]

[0145] Among them, R eout represents the formation radius controlled by each gas production well, m;

[0146] P Pmin represents the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, MPa 2 / (mPa·s);

[0147] P Pwfout represents the pseudo-pressure value corresponding to the bottom hole pressure resistance value of each gas production well, MPa 2 / (mPa·s);

[0148] P min represents the target lower limit pressure of the underground gas storage, MPa;

[0149] P max represents the upper limit pressure of the underground gas storage, MPa;

[0150] B g represents the volume coefficient of the gas in the underground gas storage;

[0151] P sc represents the pressure under standard conditions, taking 0.101325 MPa;

[0152] T sc represents the temperature under standard conditions, taking 293 K;

[0153] T represents the formation temperature of the underground gas storage, K;

[0154] η represents the pressure conductivity coefficient of the underground gas storage formation;

[0155] t out represents the gas production time of each gas production well, d;

[0156] r w represents the wellbore radius of each gas production well, m;

[0157] e represents the natural constant, with a value of 2.71828.

[0158] In a specific embodiment, the working gas volume increase determination module 503 is specifically used for:

[0159] According to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, the increased working gas volume of each gas storage unit is determined by using the traditional material balance equation;

[0160] The increased working gas volumes of each gas storage unit are accumulated to obtain the increased working gas volume of the underground gas storage reservoir.

[0161] Among them, the traditional material balance equation is:

[0162]

[0163] Among them, G represents the increased working gas volume of each gas storage unit;

[0164] represents the formation porosity of each gas production well, in decimals;

[0165] c t represents the compressibility factor of the formation rock of each gas production well, 1 / MPa;

[0166] h represents the formation thickness of each gas production well, m;

[0167] B g represents the gas volume factor in the underground gas storage reservoir;

[0168] P min represents the target lower limit pressure of the underground gas storage reservoir, MPa;

[0169] P max represents the upper limit pressure of the underground gas storage reservoir, MPa;

[0170] R eout represents the formation radius controlled by each gas production well, m.

[0171] An embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for determining the working gas volume of the underground gas storage reservoir is implemented.

[0172] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program for executing the above-mentioned method for determining the working gas volume of the underground gas storage reservoir.

[0173] In summary, the method and device for determining the working gas volume of the underground gas storage reservoir provided by the embodiments of the present invention have the following advantages:

[0174] By splitting an underground gas storage reservoir into multiple gas storage units centered around gas production wells; wherein each gas storage unit is centered around one gas production well; according to the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operating parameters of the underground gas storage reservoir, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage reservoir, calculate the formation range controlled by the gas production well to obtain the formation radius controlled by each gas production well within each gas storage unit; according to the formation radius controlled by each gas production well within each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, determine the increased working gas volume of the underground gas storage reservoir. By splitting the underground gas storage reservoir into multiple gas storage units centered around gas production wells, taking one gas storage unit as a unit, independently determine the formation radius controlled by each gas production well, and according to the formation radius controlled by each gas production well, obtain the increased working gas volume of the underground gas storage reservoir. Compared with the prior art that takes the reservoir of the entire underground gas storage reservoir as the calculation unit, it is possible to determine the increased working gas volume of the underground gas storage reservoir without solving the problem of pressure imbalance, the data is better obtained and the measurement is accurate, so that the increased gas storage volume of the working gas volume of the underground gas storage reservoir due to the reduction of the lower limit pressure can be accurately determined.

[0175] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, devices, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can 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.

[0176] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices, 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 can be implemented by computer program instructions, and the combination of processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0177] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device realizes the process in Figure 1 one process or multiple processes and / or blocks Figure 1The functions specified in one or more boxes.

[0178] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing the steps of the functions specified in one Figure 1 process or more processes and / or boxes Figure 1 or more boxes.

[0179] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for determining the working gas volume of an underground gas storage, characterized in that, Including: Splitting an underground gas storage into multiple gas storage units centered on gas production wells; wherein, each gas storage unit is centered on one gas production well; Calculating the controlled gas storage formation range of a gas production well according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, to obtain the formation radius controlled by each gas production well in each gas storage unit; Determining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage; Calculating the controlled gas storage formation range of a gas production well according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, to obtain the formation radius controlled by each gas production well in each gas storage unit, including: Calculating the formation radius controlled by each gas production well in each gas storage unit according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, through the calculation formula for the controlled gas storage formation range of the gas production well; wherein, the calculation formula for the controlled gas storage formation range of the gas production well is used to characterize the supply range of the gas production well to the gas storage formation; The calculation formula for the controlled gas storage formation range of the gas production well is: Among them, R eout represents the formation radius controlled by each gas production well; P Pmin represents the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage P Pwfout represents the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well; P min represents the target lower limit pressure of the underground gas storage P max represents the upper limit pressure of the underground gas storage B g represents the volume coefficient of the gas in the underground gas storage P sc represents the pressure under standard conditions; T sc represents the temperature under standard conditions; T represents the formation temperature of the underground gas storage; η represents the pressure conductivity coefficient of the underground gas storage formation; t out represents the gas production time of each gas production well; r w represents the wellbore radius of each gas production well; e represents the natural constant, with a value of 2.71828; Determining the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage, including: Determining the increased working gas volume of each gas storage unit according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage, using the traditional material balance equation; Accumulating the increased working gas volume of each gas storage unit to obtain the increased working gas volume of the underground gas storage.

2. The method according to claim 1, wherein The traditional material balance equation is: Wherein, G represents the increased working gas volume of each gas storage unit; represent the formation porosity of each gas production well; c t represents the compressibility of the formation rock of each gas production well; h represents the formation thickness of each gas production well; B g represents the volume coefficient of the gas in the underground gas storage P min represents the target lower limit pressure of the underground gas storage P max represents the upper limit pressure of the underground gas storage R eout represents the formation radius controlled by each gas production well.

3. An underground gas storage working gas volume determination device, characterized in that, Including: A gas storage splitting module, configured to split an underground gas storage into multiple gas storage units centered on gas production wells; wherein, each gas storage unit is centered on one gas production well; A controlled formation radius determination module, configured to calculate the controlled gas storage formation range of a gas production well according to the pseudo-pressure value corresponding to the bottom-hole pressure tolerance value of each gas production well, the operating parameters of the underground gas storage, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage, to obtain the formation radius controlled by each gas production well in each gas storage unit; A working gas volume increase determination module, configured to determine the increased working gas volume of the underground gas storage according to the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage; The controlled formation radius determination module is specifically configured to: Based on the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well, the operating parameters of the underground gas storage reservoir, and the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage reservoir, the formation radius controlled by each gas production well in each gas storage unit is obtained through the calculation formula for the controlled gas storage formation range of the gas production well; wherein, the calculation formula for the controlled gas storage formation range of the gas production well is used to represent the supply range of the gas production well to the gas storage formation. The calculation formula for the controlled gas storage formation range of the gas production well is: Among them, R eout represents the formation radius controlled by each gas production well; P Pmin represents the pseudo-pressure value corresponding to the target lower limit pressure of the underground gas storage P Pwfout represents the pseudo-pressure value corresponding to the bottom-hole pressure resistance value of each gas production well; P min represents the target lower limit pressure of the underground gas storage P max represents the upper limit pressure of the underground gas storage B g represents the volume coefficient of the gas in the underground gas storage P sc represents the pressure under standard conditions; T sc represents the temperature under standard conditions; T represents the formation temperature of the underground gas storage reservoir; η represents the pressure conductivity coefficient of the formation of the underground gas storage reservoir; t out Represents the gas production time of each gas production well; r w represents the wellbore radius of each gas production well; e represents the natural constant, with a value of 2.71828; The working gas volume increase determination module is specifically configured to: Based on the formation radius controlled by each gas production well in each gas storage unit and the target lower limit pressure of the underground gas storage reservoir, use the traditional material balance equation to determine the increased working gas volume of each gas storage unit; Accumulate the increased working gas volumes of each gas storage unit to obtain the increased working gas volume of the underground gas storage reservoir.

4. The device according to claim 3, characterized in that, The traditional material balance equation is: Wherein, G represents the increased working gas volume of each gas storage unit; represent the formation porosity of each gas production well; c t represents the compressibility of the formation rock of each gas production well; h represents the formation thickness of each gas production well; B g represents the volume coefficient of the gas in the underground gas storage P min represents the target lower limit pressure of the underground gas storage P max represents the upper limit pressure of the underground gas storage R eout Represents the formation radius controlled by each gas production well.

5. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 2.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for executing the method according to any one of claims 1 to 2.

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