Method for calculating water intrusion type gas storage reservoir capacity parameters

Abstract

This application relates to a method for calculating the storage capacity parameters of a water-submerged gas storage facility. The method includes the following steps: obtaining the initial storage capacity parameters of the water-submerged gas storage facility; obtaining the injection and production storage capacity parameters of the water-submerged gas storage facility at the end of the injection-production cycle; obtaining the cumulative gas volume change of the water-submerged gas storage facility at the end of the injection-production cycle; calculating the storage capacity parameter change of the injection-production cycle based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change; and calculating the multi-cycle storage capacity parameters of the water-submerged gas storage facility based on the storage capacity parameter change (water receding) within the gas storage facility during the injection stage and the water receding) within the gas storage facility during the production stage, thereby obtaining the storage capacity parameters of the gas storage facility for different operating cycles. The calculation method is simple and easy to understand, and is of great significance for the parameter design and operational tracking evaluation of gas storage facilities.

Description

Technical Field

[0001] This application relates to the petroleum industry, and in particular to a method for calculating the storage capacity parameters of a water-immersed gas storage facility. Background Technology

[0002] Gas storage facilities are a crucial means for national natural gas peak shaving and supply security. They require gas injection and storage during the off-season and gas extraction during the peak season to meet national needs. Currently, domestic gas storage facilities are mainly converted from depleted, constant-volume gas reservoirs. In these facilities, the underground storage space remains unchanged, and the calculation of storage capacity parameters does not consider the impact of intrusion water. Therefore, the calculated storage capacity parameters are constant values ​​over multiple operating cycles. In reality, such absolutely constant-volume gas reservoirs are very rare; most contain some edge and bottom water. During the depletion development of these reservoirs, edge and bottom water intrudes into the reservoir interior, occupying a portion of the reservoir's pore space. After a water-inundated gas reservoir is converted into a gas storage facility, during the injection phase (gas displacement) and the production phase (water extraction), some of the intruding water is discharged and re-intrudes. During the injection phase, some of the pore volume occupied by water intrusion is reoccupied by gas, and the pore volume occupied by gas before the production phase is either reoccupied by water. Therefore, gas storage facilities converted from such water-inundated gas reservoirs exhibit variable volume phenomena during operation, that is, variable volume within the injection and production cycle. During the production phase, water intrusion reduces the storage capacity, and gas injection drives water to expand the storage capacity. The storage capacity change pattern across multiple injection and production cycles shows that the storage capacity growth is initially rapid, then slows down, and gradually stabilizes. Therefore, the storage capacity parameters of a water-inundated gas storage facility are dynamic values ​​that change with the progress of injection and production, and the variable volume effect caused by water intrusion must be considered when designing storage capacity parameters.

[0003] Several issues exist regarding the calculation of storage capacity parameters for water-inundated gas storage facilities, particularly concerning the impact of water intrusion on volume variation: ① How to quantitatively describe the water intrusion volume (receding volume) during the injection and production phases of the gas storage facility during high-speed injection and production? ② How to quantitatively describe the volume variation patterns of the gas storage facility during multi-cycle injection and production operations, given the volume variation caused by water intrusion? Currently, there is no research in this area in China; therefore, it is necessary to establish a new calculation method that conforms to the requirements of water-inundated gas storage facility volume parameters. Summary of the Invention

[0004] To solve, or at least partially solve, the above-mentioned technical problems, this application provides a method for calculating the storage capacity parameters of a water-immersed gas storage facility, the method comprising the following steps:

[0005] Obtain the initial storage capacity parameters of the water-inundated gas storage facility;

[0006] Obtain the injection and production capacity parameters of the water-inundated gas storage facility at the end of the injection and production cycle;

[0007] Obtain the cumulative gas volume change of the water-inundated gas storage facility at the end of the injection-production cycle;

[0008] The change in storage capacity parameters during the injection-production cycle is calculated based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change.

[0009] The multi-cycle storage capacity parameters of the water-inundated gas storage facility are calculated based on the changes in the storage capacity parameters.

[0010] Preferably, obtaining the initial storage capacity parameters of the water-submerged gas storage facility includes the following steps:

[0011] Obtain the initial formation pressure of the water-inundated gas storage facility;

[0012] Obtain the initial storage capacity of the water-inundated gas storage facility;

[0013] Obtain the initial total water intrusion volume of the water-intrusion type gas storage facility;

[0014] Obtain the average production water-to-gas ratio of the water-inundated gas storage facility.

[0015] Preferably, obtaining the injection and production capacity parameters of the water-submerged gas storage facility at the end of the injection and production cycle includes the following steps:

[0016] Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas production cycle;

[0017] Obtain the gas storage capacity of the water-immersed gas storage facility at the end of the gas extraction cycle;

[0018] Obtain the total water intrusion volume of the water-intrusion type gas storage at the end of the gas extraction cycle;

[0019] Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas injection cycle;

[0020] Obtain the gas injection capacity of the water-immersed gas storage tank at the end of the gas injection cycle;

[0021] Obtain the total water intrusion volume of the water-intrusion type gas storage tank at the end of the gas injection cycle.

[0022] Preferably, obtaining the cumulative gas volume change of the water-submerged gas storage facility at the end of the injection-production cycle includes the following steps:

[0023] Obtain the cumulative gas extraction volume of the water-immersed gas storage facility at the end of the gas extraction cycle;

[0024] The cumulative gas injection volume of the water-immersed gas storage tank at the end of the gas injection cycle is obtained.

[0025] Preferably, the step of calculating the change in storage capacity parameters during the injection-production cycle based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change includes the following steps:

[0026] Obtain the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change of the water-inundated gas storage facility;

[0027] The water intrusion volume and gas storage capacity of the water-intrusion type gas storage tank during the gas production cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change.

[0028] The water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas injection cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change.

[0029] Preferably, the step of calculating the water intrusion volume and gas storage capacity of the water-intrusion type gas storage tank during the gas production cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps:

[0030] Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility;

[0031] Obtain the formation pressure, storage capacity, and total water intrusion volume of the water-intruded gas storage facility;

[0032] Obtain the cumulative gas extraction volume of the water-inundated gas storage facility;

[0033] Obtain the gas production material balance equation for water-drive variable volume gas reservoirs;

[0034] Define the gas extraction error function;

[0035] The gas extraction error function is solved iteratively using Newton's method, and the first function solution is obtained.

[0036] Calculate the water production during the gas production cycle, the water intrusion change during the gas production cycle, and the first water storage coefficient based on the solution of the first function.

[0037] Calculate the water intrusion volume and storage capacity of the water-intrusion type gas storage facility.

[0038] Preferably, the expression for the gas production material balance equation of the water-drive variable volume gas reservoir is:

[0039] ,

[0040] Wherein, P1 represents the formation pressure of the gas production area, and Z1 represents the gas deviation factor corresponding to the formation pressure of the gas production area. This represents the initial formation pressure. This represents the gas deviation factor under the initial formation pressure. This represents the cumulative gas extraction volume. This indicates the initial library capacity. This represents the first water storage coefficient.

[0041] Preferably, the step of calculating the water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas injection cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps:

[0042] Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility;

[0043] Obtain the injection formation pressure, injection storage capacity, and total water intrusion volume of the water-intruded gas storage facility;

[0044] Obtain the cumulative gas injection volume of the water-immersed gas storage facility;

[0045] Obtain the gas injection material balance equation for water-drive variable volume gas reservoirs;

[0046] Define the gas injection error function;

[0047] The gas injection error function is solved iteratively using Newton's method to obtain the second function solution;

[0048] The water intake during the gas injection cycle, the water intrusion change during the gas injection cycle, and the second water storage coefficient are calculated based on the solution of the second function.

[0049] Calculate the water intrusion volume and gas storage capacity of the water-intrusion type gas storage facility.

[0050] Preferably, the expression for the mass balance equation of the water-drive variable volume gas reservoir injection is:

[0051] ,

[0052] Wherein, P2 represents the gas injection formation pressure, and Z2 represents the gas deviation factor corresponding to the gas injection formation pressure. This represents the initial formation pressure. This represents the gas deviation factor under the initial formation pressure. This indicates the cumulative gas injection volume. This indicates the initial library capacity. This represents the second water storage coefficient.

[0053] Preferably, the step of calculating the multi-cycle storage capacity parameters of the water-submerged gas storage facility based on the changes in the storage capacity parameters includes the following steps:

[0054] Calculate the foundation gas volume of the water-submerged gas storage facility;

[0055] Calculate the current cushion gas volume of the water-submerged gas storage facility;

[0056] Calculate the current water intrusion volume of the aforementioned water-intrusion gas storage facility;

[0057] Calculate the initial volume dynamic curve of the water-inundated gas storage tank;

[0058] Calculate the storage capacity of the water-inundated gas storage facility during multiple injection and production cycles;

[0059] Calculate the water intrusion volume during multiple injection and production cycles of the water-intrusion type gas storage facility;

[0060] Calculate the final capacity parameters of the water-inundated gas storage facility during its capacity-reaching period.

[0061] The technical solutions provided in this application have the following advantages compared with the prior art:

[0062] This application provides a method for calculating the storage capacity parameters of a water-inundated gas storage facility. Based on the changes in water inflow (water receding) during the gas injection phase and the changes in water inflow (water entering) during the gas production phase, the method calculates the quantitative changes in the gas storage space of the underground gas storage facility, thereby obtaining the storage capacity parameters for different operating cycles. This method can calculate the changes in water inflow and storage capacity of a water-inundated gas storage facility during different injection and production cycles, providing a simple and easy-to-implement method for calculating the storage capacity parameters of water-inundated gas storage facilities and clarifying the changing patterns of the storage capacity. The calculation method is simple and easy to understand, and it is of great significance for the parameter design and operational tracking evaluation of gas storage facilities. Attached Figure Description

[0063] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0064] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 A flowchart illustrating a method for calculating the storage capacity parameters of a water-inundated gas storage facility, provided in an embodiment of this application;

[0066] Figure 2 A diagram showing the relationship between storage capacity and pressure in a water-immersed gas storage facility, provided as an embodiment of this application, illustrates a method for calculating storage capacity parameters in such a facility.

[0067] Figure 3 A schematic diagram of dynamic storage capacity and water intrusion volume for a method of calculating storage capacity parameters of a water-intrusion type gas storage facility provided in this application embodiment;

[0068] Figure 4 A schematic diagram of the water intrusion amount and cumulative gas production curves for a water-intrusion type gas storage capacity parameter calculation method provided in this application embodiment;

[0069] Figure 5 A schematic diagram of the water intrusion variation curve during multi-cycle operation of a water-intrusion type gas storage capacity parameter calculation method provided in this application embodiment;

[0070] Figure 6 This is a schematic diagram of the capacity design curve for a multi-cycle operation of a water-inundated gas storage facility, provided as an embodiment of this application, for calculating storage capacity parameters. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0072] Figure 1 This is a flowchart illustrating a method for calculating the storage capacity parameters of a water-inundated gas storage facility, as provided in an embodiment of this application.

[0073] In this application embodiment, a method for calculating the storage capacity parameters of a water-immersed gas storage facility is provided, the method comprising the following steps:

[0074] S1: Obtain the initial storage capacity parameters of the water-inundated gas storage facility;

[0075] In this embodiment of the application, obtaining the initial storage capacity parameters of the water-immersed gas storage facility in step S1 includes the following steps:

[0076] Obtain the initial formation pressure of the water-inundated gas storage facility;

[0077] Obtain the initial storage capacity of the water-inundated gas storage facility;

[0078] Obtain the initial total water intrusion volume of the water-intrusion type gas storage facility;

[0079] Obtain the average production water-to-gas ratio of the water-inundated gas storage facility.

[0080] In this embodiment of the application, when obtaining the initial storage capacity parameters of a water-inundated gas storage facility, the main parameters obtained are: initial formation pressure, initial storage capacity, initial total water inundation, and average production water-to-gas ratio. Specifically, these parameters can all be obtained through corresponding sensors.

[0081] S2: Obtain the injection and production capacity parameters of the water-inundated gas storage facility at the end of the injection and production cycle;

[0082] In this embodiment of the application, the step S2 of obtaining the injection and production capacity parameters of the water-submerged gas storage facility at the end of the injection and production cycle includes the following steps:

[0083] Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas production cycle;

[0084] Obtain the gas storage capacity of the water-immersed gas storage facility at the end of the gas extraction cycle;

[0085] Obtain the total water intrusion volume of the water-intrusion type gas storage at the end of the gas extraction cycle;

[0086] Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas injection cycle;

[0087] Obtain the gas injection capacity of the water-immersed gas storage tank at the end of the gas injection cycle;

[0088] Obtain the total water intrusion volume of the water-intrusion type gas storage tank at the end of the gas injection cycle.

[0089] In this embodiment of the application, when acquiring the injection and production capacity parameters of the water-inundated gas storage tank at the end of the injection-production cycle, the acquired parameters are those at the end of the production cycle and those at the end of the injection cycle, specifically: production formation pressure, production storage capacity, total water inundation during production, injection formation pressure, injection storage capacity, and total water inundation during injection. These parameters can be acquired using corresponding sensors.

[0090] S3: Obtain the cumulative gas volume change of the water-inundated gas storage tank at the end of the injection-production cycle;

[0091] In this embodiment of the application, the step S3 of obtaining the cumulative gas volume change of the water-submerged gas storage tank at the end of the injection-production cycle includes the following steps:

[0092] Obtain the cumulative gas extraction volume of the water-immersed gas storage facility at the end of the gas extraction cycle;

[0093] The cumulative gas injection volume of the water-immersed gas storage tank at the end of the gas injection cycle is obtained.

[0094] In this embodiment of the application, when the cumulative gas volume change of the water-submerged gas storage at the end of the injection-production cycle is obtained, the cumulative gas production volume of the water-submerged gas storage at the end of the production cycle and the cumulative gas injection volume of the water-submerged gas storage at the end of the injection cycle are obtained respectively. Specifically, these parameters can be obtained through corresponding sensors.

[0095] S4: Calculate the change in storage capacity parameters during the injection-production cycle based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change;

[0096] In this embodiment of the application, step S4, which calculates the change in storage capacity parameters during the injection-production cycle based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change, includes the following steps:

[0097] Obtain the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change of the water-inundated gas storage facility;

[0098] The water intrusion volume and gas storage capacity of the water-intrusion type gas storage tank during the gas production cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change.

[0099] The water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas injection cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change.

[0100] In this embodiment of the application, when each parameter is obtained sequentially through steps S1-S3, the changes in storage capacity parameters during the injection-production cycle can be calculated based on these parameters. Specifically, the water intrusion volume and storage capacity of the water-intruded gas storage during the production cycle can be calculated based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume changes. The water intrusion volume and storage capacity of the water-intruded gas storage during the injection cycle can be calculated based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume changes.

[0101] In this embodiment of the application, the step of calculating the water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas production cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps:

[0102] Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility;

[0103] Obtain the formation pressure, storage capacity, and total water intrusion volume of the water-intruded gas storage facility;

[0104] Obtain the cumulative gas extraction volume of the water-inundated gas storage facility;

[0105] Obtain the gas production material balance equation for water-drive variable volume gas reservoirs;

[0106] Define the gas extraction error function;

[0107] The gas extraction error function is solved iteratively using Newton's method, and the first function solution is obtained.

[0108] Calculate the water production during the gas production cycle, the water intrusion change during the gas production cycle, and the first water storage coefficient based on the solution of the first function.

[0109] Calculate the water intrusion volume and storage capacity of the water-intrusion type gas storage facility.

[0110] In this embodiment of the application, when calculating the gas production water intrusion and gas production capacity of the water-intruded gas storage tank during the gas production cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change, the gas production material balance equation of the water-driven variable volume gas reservoir is first obtained, and a gas production error function is defined. Then, the gas production error function is solved iteratively using the Newton method to obtain the first function solution. Based on the first function solution, the gas production water volume, the gas production cycle water intrusion change, and the first water storage coefficient are calculated. Finally, the gas production water intrusion and gas production capacity of the water-intruded gas storage tank are calculated.

[0111] In this embodiment, the expression for the gas production material balance equation of the water-drive variable volume gas reservoir is:

[0112] (Equation 1)

[0113] Wherein, P1 represents the formation pressure of the gas production area, and Z1 represents the gas deviation factor corresponding to the formation pressure of the gas production area. This represents the initial formation pressure. This represents the gas deviation factor under the initial formation pressure. This represents the cumulative gas extraction volume. This indicates the initial library capacity. This represents the first water storage coefficient.

[0114] In the embodiments of this application, the gas sampling error function The expression is:

[0115] (Equation 2)

[0116] The gas extraction error function is solved iteratively using Newton's method, and its expression is:

[0117] (Equation 3)

[0118] The formula for calculating the water production during the gas extraction stage is:

[0119] (Equation 4)

[0120] The expression for calculating the water intrusion change during the gas production stage is as follows:

[0121] (Equation 5)

[0122] The first water storage coefficient for the gas extraction stage is calculated using the following expression:

[0123] (Equation 6)

[0124] The total water intrusion during the gas production stage is calculated using the following expression:

[0125] (Equation 7)

[0126] The storage capacity during the gas extraction stage is calculated using the following expression:

[0127] (Equation 8)

[0128] Where: P1——gas production formation pressure, in megapascals (MPa);

[0129] —Initial formation pressure, in megapascals (MPa);

[0130] Z1 — Gas deviation factor corresponding to the formation pressure of the gas production area, dimensionless;

[0131] —Gas deviation factor under initial formation pressure, dimensionless;

[0132] —Cumulative gas production, in 100 million cubic meters (10 8 m 3 );

[0133] —Previous cycle storage capacity, in 100 million cubic meters (10 8 m 3 );

[0134] —First water storage coefficient, dimensionless;

[0135] —Water production during the gas extraction stage, in units of 10,000 cubic meters (10 4 m 3 );

[0136] —Cumulative water intrusion during the gas reservoir development stage, in units of 10,000 cubic meters (10 4 m 3 );

[0137] —Changes in water intrusion during the gas extraction stage, in units of 10,000 cubic meters (10 4 m 3 );

[0138] —Gas extraction and water displacement efficiency, expressed as a percentage;

[0139] —Water volume coefficient, dimensionless;

[0140] —Gas volume coefficient under initial formation pressure, dimensionless;

[0141] —Total water intrusion during the gas extraction stage, in units of 10,000 cubic meters (10 4 m 3 );

[0142] —Water intrusion during the first gas production phase of the gas storage facility, in units of 10,000 cubic meters (10 4 m 3 );

[0143] —Changes in water intrusion during the gas storage operation phase, in units of 10,000 cubic meters (10 4 m 3 );

[0144] —Average production water-to-gas ratio, in m³ 3 / 10 4 m 3 ;

[0145] —Gas extraction stage storage capacity, in 100 million cubic meters (10 8 m 3 ).

[0146] In this embodiment of the application, the step of calculating the water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas injection cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps:

[0147] Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility;

[0148] Obtain the injection formation pressure, injection storage capacity, and total water intrusion volume of the water-intruded gas storage facility;

[0149] Obtain the cumulative gas injection volume of the water-immersed gas storage facility;

[0150] Obtain the gas injection material balance equation for water-drive variable volume gas reservoirs;

[0151] Define the gas injection error function;

[0152] The gas injection error function is solved iteratively using Newton's method to obtain the second function solution;

[0153] The water intake during the gas injection cycle, the water intrusion change during the gas injection cycle, and the second water storage coefficient are calculated based on the solution of the second function.

[0154] Calculate the water intrusion volume and gas storage capacity of the water-intrusion type gas storage facility.

[0155] In this embodiment of the application, when calculating the water intrusion and gas injection capacity of the water-intruded gas storage tank during the gas injection cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change, the gas injection material balance equation of the water-driven variable volume gas reservoir is first obtained, and the gas injection error function is defined. Then, the gas injection error function is solved iteratively using the Newton method to obtain the second function solution. Based on the second function solution, the water production during the gas injection cycle, the water intrusion change during the gas injection cycle, and the second water storage coefficient are calculated. Finally, the water intrusion and gas injection capacity of the water-intruded gas storage tank are calculated.

[0156] In this embodiment, the expression for the mass balance equation of the water-drive variable volume gas reservoir injection is:

[0157] (Equation 9)

[0158] Wherein, P2 represents the gas injection formation pressure, and Z2 represents the gas deviation factor corresponding to the gas injection formation pressure. This represents the initial formation pressure. This represents the gas deviation factor under the initial formation pressure. This indicates the cumulative gas injection volume. This indicates the initial library capacity. This represents the second water storage coefficient.

[0159] In this embodiment of the application, the gas injection error function The expression is:

[0160] (Equation 10)

[0161] The gas injection error function is solved iteratively using Newton's method, and its expression is:

[0162] (Equation 11)

[0163] The expression for calculating the water intrusion change during the gas injection stage is:

[0164] (Equation 12)

[0165] The second water storage coefficient is calculated using the following expression:

[0166] (Equation 13)

[0167] The total water intrusion during the gas injection stage is calculated using the following expression:

[0168] (Equation 14)

[0169] The formula for calculating the reservoir capacity during the gas injection stage is:

[0170] (Equation 15)

[0171] Where: P2——Gas injection formation pressure, in megapascals (MPa);

[0172] —Initial formation pressure, in megapascals (MPa);

[0173] Z2 — Gas deviation factor corresponding to the gas injection formation pressure, dimensionless;

[0174] —Changes in water intrusion during the gas injection stage, in units of 10,000 cubic meters (10 4 m 3 );

[0175] —Total water intrusion during the gas injection stage, in 10,000 cubic meters (10 4 m 3 );

[0176] —The second water storage coefficient is dimensionless;

[0177] —Cumulative gas injection volume, in 100 million cubic meters (10 8 m 3 );

[0178] —Cumulative gas production, in 100 million cubic meters (10 8 m 3 );

[0179] —Previous cycle storage capacity, in 100 million cubic meters (10 8 m 3 );

[0180] E i —Injection-water displacement efficiency, expressed as a percentage;

[0181] —Storage capacity during the gas injection stage, in 100 million cubic meters (10 8 m 3 ).

[0182] S5: Calculate the multi-cycle storage capacity parameters of the water-inundated gas storage facility based on the changes in the storage capacity parameters.

[0183] In this embodiment of the application, step S5, calculating the multi-cycle storage capacity parameters of the water-submerged gas storage facility based on the changes in storage capacity parameters, includes the following steps:

[0184] Calculate the foundation gas volume of the water-submerged gas storage facility;

[0185] Calculate the current cushion gas volume of the water-submerged gas storage facility;

[0186] Calculate the current water intrusion volume of the aforementioned water-intrusion gas storage facility;

[0187] Calculate the initial volume dynamic curve of the water-inundated gas storage tank;

[0188] Calculate the storage capacity of the water-inundated gas storage facility during multiple injection and production cycles;

[0189] Calculate the water intrusion volume during multiple injection and production cycles of the water-intrusion type gas storage facility;

[0190] Calculate the final capacity parameters of the water-inundated gas storage facility during its capacity-reaching period.

[0191] In this embodiment of the application, when calculating the multi-cycle storage capacity parameters of the water-inundated gas storage facility based on the changes in the storage capacity parameters, the multi-cycle storage capacity parameters include: basic cushion gas volume, current cushion gas volume, current water inundation volume, initial capacity dynamic curve, storage capacity during multiple injection and production cycles, water inundation volume during multiple injection and production cycles, and storage capacity parameters during the final capacity-reaching cycle. Specifically, the basic cushion gas volume represents the remaining storage capacity after the initial formation pressure decreases to the abandonment pressure, and the unit is 100 million cubic meters (10^15 cubic meters). 8 m 3 The current cushion gas volume represents the remaining storage capacity from the initial pressure to the current pressure, expressed in 100 million cubic meters (10). 8 m 3 The current water inrush volume represents the amount of water inrushed during the initial extraction process, from the initial pressure to the current pressure, expressed in 100 million cubic meters (10). 8 m 3 The initial capacity dynamic curve represents the relationship between reservoir capacity and water intrusion during the process of decreasing from the original formation pressure to the abandoned pressure. The reservoir capacity during multiple injection-production cycles includes: the capacity increased by gas injection to the upper limit pressure of the reservoir, and the capacity decreased by gas production to the lower limit pressure of the reservoir. The water intrusion during multiple injection-production cycles includes: the water intrusion increased by gas injection to the upper limit pressure of the reservoir, and the water intrusion decreased by gas production to the lower limit pressure of the reservoir. The maximum reservoir capacity is the reservoir capacity at the end of gas injection when the reservoir reaches its full capacity. The total cushion gas volume is the reservoir capacity at the end of gas production when the reservoir reaches its full capacity. The additional cushion gas volume is the difference between the total cushion gas volume and the basic cushion gas volume. The supplementary cushion gas volume is the difference between the reservoir capacity at the end of gas production and the current reservoir capacity, i.e., the supplementary gas volume required to increase the reservoir pressure from the current pressure to the lower limit pressure.

[0192] The present application will now be described in detail with reference to specific embodiments.

[0193] Based on dynamic reserves analysis (see...) Figure 3 The original gas reserves and water intrusion patterns of a water-driven variable-volume gas reservoir were obtained using the gas production material balance equation (see...). Figure 4 Through trial calculations, the basic parameters for reservoir capacity design were determined by taking a gas injection water displacement efficiency of 64% and a gas production water intrusion efficiency of 35% (Table 1).

[0194] Table 1 Basic Parameters for Warehouse Capacity Design

[0195]

[0196] Based on the operating pattern of gas storage facilities, the capacity-reaching cycle is generally 5 cycles, during which the storage capacity reaches the original storage capacity. The storage capacity design indicators for the capacity-reaching cycle are shown in Table 2.

[0197] Table 2 Storage Capacity Design Parameters

[0198]

[0199] The multi-period water intrusion variation curves are shown below. Figure 5 The storage capacity design curve for multi-cycle operation is shown in [reference]. Figure 6 ,according to Figure 2 The calculation template can obtain the storage capacity parameter values ​​for each cycle. The storage capacity parameters for multi-cycle operation are shown in Table 3. The maximum storage capacity of this scheme is 432 million cubic meters, and the working gas volume is 286 million cubic meters.

[0200] Table 3. Calculation Table of Storage Capacity Parameters for Multi-Period Operation

[0201]

[0202] like Figure 5 , Figure 6 As shown, the variable volume calculation method and the variation law of water intrusion established in this study can describe the special phenomenon of "variable volume within a period" in water-driven gas reservoirs.

[0203] This application provides a method for calculating the storage capacity parameters of a water-inundated gas storage facility. Based on the changes in water inflow (water receding) during the gas injection phase and the changes in water inflow (water entering) during the gas production phase, the method calculates the quantitative changes in the gas storage space of the underground gas storage facility, thereby obtaining the storage capacity parameters for different operating cycles. This method can calculate the changes in water inflow and storage capacity of a water-inundated gas storage facility during different injection and production cycles, providing a simple and easy-to-implement method for calculating the storage capacity parameters of water-inundated gas storage facilities and clarifying the changing patterns of the storage capacity. The calculation method is simple and easy to understand, and it is of great significance for the parameter design and operational tracking evaluation of gas storage facilities.

[0204] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0205] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A water intrusion type gas storage reservoir capacity parameter calculation method, characterized in that, The method includes the following steps: Obtain the initial storage capacity parameters of the water-inundated gas storage facility; Obtain the injection and production capacity parameters of the water-inundated gas storage facility at the end of the injection and production cycle; Obtain the cumulative gas volume change of the water-inundated gas storage facility at the end of the injection-production cycle; The change in storage capacity parameters during the injection-production cycle is calculated based on the initial storage capacity parameters, the injection-production storage capacity parameters, and the cumulative gas volume change. Calculate the multi-period storage capacity parameters of the water-inundated gas storage facility based on the changes in the storage capacity parameters; The calculation of the storage capacity parameter change during the injection-production cycle based on the initial storage capacity parameter, the injection-production storage capacity parameter, and the cumulative gas volume change includes: The water intrusion volume and gas storage capacity of the water-intrusion type gas storage tank during the gas production cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change. The water intrusion volume and gas storage capacity of the water-intrusion type gas storage tank during the gas injection cycle are calculated based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change. The step of calculating the water intrusion volume and gas storage capacity of the water-intruded gas storage facility during the gas production cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps: Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility; Obtain the formation pressure, storage capacity, and total water intrusion volume of the water-intruded gas storage facility; Obtain the cumulative gas extraction volume of the water-inundated gas storage facility; Obtain the gas production material balance equation for water-drive variable volume gas reservoirs; Define the gas extraction error function; The gas extraction error function is solved iteratively using Newton's method, and the first function solution is obtained. Calculate the water production during the gas production cycle, the water intrusion change during the gas production cycle, and the first water storage coefficient based on the solution of the first function. Calculate the water intrusion volume and gas storage capacity of the water-intrusion type gas storage facility; The expression for the gas production material balance equation of the water-drive variable volume gas reservoir is as follows: The expression for the gas extraction error function is: The expression for the first water storage coefficient is: Wherein, P1 represents the formation pressure of the gas production area, and Z1 represents the gas deviation factor corresponding to the formation pressure of the gas production area. This represents the initial formation pressure. This represents the gas deviation factor under the initial formation pressure. This represents the cumulative gas extraction volume. This indicates the initial library capacity. This represents the first water storage coefficient. B represents the change in water intrusion during the gas extraction stage. gr Indicates the gas volume factor under initial formation pressure; The step of calculating the water intrusion volume and gas storage capacity of the water-intruded gas storage tank during the gas injection cycle based on the initial storage capacity parameters, the injection and production storage capacity parameters, and the cumulative gas volume change includes the following steps: Obtain the initial formation pressure, initial storage capacity, initial total water intrusion, and average production water-to-gas ratio of the water-intrusion gas storage facility; Obtain the injection formation pressure, injection storage capacity, and total water intrusion volume of the water-intruded gas storage facility; Obtain the cumulative gas injection volume of the water-immersed gas storage facility; Obtain the gas injection material balance equation for water-drive variable volume gas reservoirs; Define the gas injection error function; The gas injection error function is solved iteratively using Newton's method to obtain the second function solution; The water intake during the gas injection cycle, the water intrusion change during the gas injection cycle, and the second water storage coefficient are calculated based on the solution of the second function. Calculate the water intrusion volume and gas storage capacity of the water-intrusion type gas storage facility; The expression for the mass balance equation of the water-drive variable volume gas reservoir injection is: The expression for the gas injection error function is: The expression for the second water storage coefficient is: Wherein, P2 represents the gas injection formation pressure, and Z2 represents the gas deviation factor corresponding to the gas injection formation pressure. This indicates the cumulative gas injection volume. This represents the second water storage coefficient. This indicates the change in water intrusion during the gas injection stage.

2. The method for calculating the storage capacity parameters of a water-immersed gas storage facility according to claim 1, characterized in that, The steps for obtaining the initial storage capacity parameters of the water-submerged gas storage facility include: Obtain the initial formation pressure of the water-inundated gas storage facility; Obtain the initial storage capacity of the water-inundated gas storage facility; Obtain the initial total water intrusion volume of the water-intrusion type gas storage facility; Obtain the average production water-to-gas ratio of the water-inundated gas storage facility.

3. The method for calculating the storage capacity parameters of a water-immersed gas storage facility according to claim 1, characterized in that, The steps for obtaining the injection and production capacity parameters of the water-submerged gas storage facility at the end of the injection and production cycle include: Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas production cycle; Obtain the gas storage capacity of the water-inundated gas storage facility at the end of the gas extraction cycle; Obtain the total water intrusion volume of the water-intrusion type gas storage facility at the end of the gas extraction cycle; Obtain the formation pressure of the water-inundated gas storage facility at the end of the gas injection cycle; Obtain the gas injection capacity of the water-immersed gas storage facility at the end of the gas injection cycle; Obtain the total water intrusion volume of the water-intrusion type gas storage tank at the end of the gas injection cycle.

4. The method for calculating the storage capacity parameters of a water-immersed gas storage facility according to claim 1, characterized in that, The steps for obtaining the cumulative gas volume change of the water-submerged gas storage facility at the end of the injection-production cycle include: Obtain the cumulative gas extraction volume of the water-immersed gas storage facility at the end of the gas extraction cycle; The cumulative gas injection volume of the water-immersed gas storage tank at the end of the gas injection cycle is obtained.

5. The method for calculating the storage capacity parameters of a water-immersed gas storage facility according to claim 1, characterized in that, The step of calculating the multi-period storage capacity parameters of the water-submerged gas storage facility based on the changes in storage capacity parameters includes the following steps: Calculate the foundation gas volume of the water-submerged gas storage facility; Calculate the current cushion gas volume of the water-submerged gas storage facility; Calculate the current water intrusion volume of the aforementioned water-intrusion gas storage facility; Calculate the initial volume dynamic curve of the water-inundated gas storage tank; Calculate the storage capacity of the water-inundated gas storage facility during multiple injection and production cycles; Calculate the water intrusion volume during multiple injection and production cycles of the water-intrusion type gas storage facility; Calculate the final capacity parameters of the water-inundated gas storage facility during its capacity-reaching period.

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