A method for evaluating working gas volume by setting lower limit pressure of gas storage

Abstract

The present invention relates to the technical field of underground gas storage, and specifically to a method for evaluating working gas volume by setting a lower limit pressure of a gas storage. The method comprises establishing three curves, namely, a working gas volume relationship curve for evaluating material balance of the gas storage, a working gas volume relationship curve for evaluating daily gas injection capacity of a gas injection well, and a working gas volume relationship curve for evaluating daily gas production capacity of a gas production well. The three established curves are then placed in the same coordinate system to obtain an intersection curve diagram, and the upper limit pressure when the gas storage is in injection-production balance is determined, thereby determining the working gas volume and storage capacity of the gas storage. The determined upper limit pressure, working gas volume and storage capacity of the gas storage are applied to the determination of the construction type of the gas storage and the design and implementation of the drilling engineering and ground engineering of the gas storage, so as to achieve the optimal configuration of the engineering facilities and the storage and peak-shaving capacity of the gas storage in the production operation of the gas storage, avoid construction waste or limitation, and maximize the economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of underground gas storage, and in particular to a method for evaluating working gas volume of a gas storage by setting a lower limit pressure. Background Art

[0002] Underground gas storage generally refers to the use of the original underground storage space, injecting natural gas into the gas storage for storage during the off-season, and quickly taking out the natural gas during the peak season, so as to achieve the purpose of peak regulation and energy security. However, to ensure a certain injection and production capacity of the gas well, the formation pressure needs to be maintained within a certain range. The currently commonly used evaluation method for gas storage operation indicators is based on the material balance equation (pressure drop curve). Generally, the upper limit pressure of the gas storage operation is determined by the original formation pressure of the gas reservoir or based on indicators such as the sealing of the gas reservoir, and the formation pressure corresponding to the production capacity required at the end of gas production is determined as the lower limit pressure. The natural gas production corresponding to the operating pressure range is the working gas volume of the gas storage. Then, according to the evaluation results of the injection and production capacity of the gas well and the working system, the required number of injection and production wells is calculated. Some gas storages may need to be constructed without injecting bottom gas, and the current formation pressure is the lower limit pressure. There may also be a gradual increase in the pressure operation range, that is, gradually increase the lower limit pressure for multi-stage construction, and use the existing developed gas fields and gas storage to build together. The relationship between storage capacity, operating pressure (upper and lower pressure limits), working gas volume, number of injection and production wells, and gas well injection and production capacity is mutually matched and changes in coordination. How to evaluate the upper pressure limit, working gas volume, storage capacity and other indicators under the conditions of limited well number, injection and production time, lower pressure limit and remaining reserves to achieve injection and production balance of gas storage is a difficult problem faced by this type of gas storage. Summary of the invention

[0003] The present invention overcomes the shortcomings of the prior art and provides a method for evaluating the working gas volume of a gas storage facility by setting a lower limit pressure. Under the conditions of limiting the number of wells, injection and production time, lower limit pressure and remaining reserves, the upper limit pressure, working gas volume, storage capacity and other indicators are evaluated to achieve a technical method for injection and production balance of the gas storage facility, thereby meeting the evaluation indicator requirements for building a gas storage facility in the above special circumstances.

[0004] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0005] A method for evaluating working gas volume by setting a lower limit pressure of a gas storage reservoir comprises the following steps

[0006] Step 1: Use the material balance method to evaluate the working gas volume and establish the material balance evaluation working gas volume relationship curve of the gas storage reservoir;

[0007] Step 2: Use the gas injection capacity evaluation working gas volume method to establish a daily gas injection capacity evaluation working gas volume relationship curve for the gas injection well;

[0008] Step 3: Use the gas production capacity evaluation working gas volume method to establish a working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well;

[0009] Step 4: Using the three relationship curves in step 1, step 2 and step 3, place the three curves in the same coordinate system to obtain an intersection curve, determine the upper limit pressure of the gas storage when the gas storage is in injection-production balance, and thus determine the working gas volume and storage capacity of the gas storage;

[0010] Step 5: The upper limit pressure of the gas storage, the working gas volume of the gas storage and the storage capacity of the gas storage determined in step 4 are applied to the determination of the construction type of the gas storage and the design and implementation of the gas storage drilling project and ground engineering.

[0011] Furthermore, the material balance evaluation working gas volume method comprises the following steps:

[0012] ①: Establish the gas reservoir material balance relationship curve between the natural gas geological reserves G of the gas storage and the apparent formation pressure P / Z;

[0013] ②: Determine the lower limit pressure P of the gas storage min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) ;

[0014] ③: Assume that there are multiple upper limit pressure nodes P of the gas storage max(i) And the corresponding apparent upper limit pressure P max(i) / Z max(i) , using the gas reservoir material balance relationship curve in ①, determine the storage capacity G corresponding to a certain apparent upper limit pressure node of the gas storage reservoir k(i) , by using the storage capacity G corresponding to the apparent upper limit pressure node k(i) and the cushion gas volume G in ② r(0) The difference between the working gas volume G iwork(i) The method is used to obtain each assumed upper limit pressure node P of the gas storage. max(i) The corresponding working gas volume G iwork(i) , and establish the working gas volume relationship curve for material balance evaluation of gas storage.

[0015] Furthermore, the gas injection capacity evaluation working gas volume method comprises the following steps:

[0016] Determine the number of gas injection wells N in and gas injection time D in , determine the lower limit pressure P of a single gas injection well imin , assuming that the gas injection well has multiple upper limit pressure nodes P max(j); Establish the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, and determine the lower limit pressure P of a single gas injection well imin The corresponding daily gas injection capacity Q inmin and select an upper limit pressure node P from multiple upper limit pressure nodes of a single gas injection well max(j) The corresponding daily gas injection capacity Q inmax(j) , and then determine the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) The daily gas injection capacity Q corresponding to the multiple formation pressure nodes between (x) , the working gas volume G corresponding to a certain upper limit pressure node of the gas injection well of the gas storage reservoir is obtained by calculation iwork注(j) ; Then calculate the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) Each assumed upper limit pressure node between and its corresponding working gas volume G iwork注(j) , and draw the relationship curve between each upper limit pressure node of the gas storage reservoir injection well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily injection capacity of the gas injection well.

[0017] Furthermore, the gas production capacity evaluation working gas volume method comprises the following steps:

[0018] Determine the number of gas wells N p and gas sampling time D P , determine the lower limit pressure P of a single gas well pmin , assuming that there are multiple upper limit pressure nodes P of a single gas well max(k) , establish the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, and determine the lower limit pressure P of a single gas well pmin The corresponding daily gas production capacity Q pmin and a certain upper limit pressure node P among multiple upper limit pressure nodes of a single gas production well max(k) The corresponding daily gas production capacity Q pmax(k) Then determine the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) The daily gas injection capacity Q corresponding to the multiple formation pressure nodes between (y) , the working gas volume G corresponding to a certain upper limit pressure node of the gas well of the gas storage reservoir is obtained by calculation iwork采(k) ; Then calculate the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) Each assumed upper limit pressure node and its corresponding working gas volume G iwork采(k), and draw the relationship curve between each upper limit pressure node of the gas storage reservoir's gas production well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well.

[0019] Furthermore, the material balance relationship curve between the geological reserves G of the gas storage and the apparent formation pressure P / Z in the gas storage facility established in ① also includes the following method:

[0020] S1: Obtain the cumulative geological gas production of natural gas in the gas storage facility G p , formation pressure P and the natural gas deviation coefficient Z corresponding to the formation pressure P, determine the apparent formation pressure as the ratio of the formation pressure P to the natural gas deviation coefficient Z corresponding to it = P / Z, and establish the natural gas geological cumulative gas production G P The relationship curve of the apparent formation pressure P / Z corresponding to it. When the apparent formation pressure P / Z = 0, the corresponding cumulative gas production volume of natural gas is G P = Natural gas geological reserves G;

[0021] S2: Obtain the original formation pressure P of the gas reservoir of the reconstructed gas storage facility i and its corresponding natural gas deviation coefficient Z i , the original apparent formation pressure before gas reservoir development is determined as the original formation pressure P i Its original formation pressure P i The corresponding natural gas deviation coefficient Z i The ratio of = P i / Z i , according to the original apparent formation pressure P i / Z i The relationship between the gas geological reserves G in step S1 is used to establish a gas reservoir material balance relationship curve.

[0022] Furthermore, the lower limit pressure P of the gas storage is determined in the above ② min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) Includes the following methods

[0023] S01: The current formation pressure or the specified formation pressure is determined as the lower limit pressure P of the gas storage reservoir. min ;

[0024] S02: Lower limit pressure P of gas storage min The corresponding natural gas deviation coefficient is Z min , determine the lower limit pressure P of the gas storage min The corresponding natural gas deviation coefficient Z mi The ratio is the apparent lower limit formation pressure P of the gas storage reservoir. min / Zmin ;

[0025] S03: Based on the determined apparent lower limit formation pressure P of the gas storage reservoir min / Z min The corresponding natural gas geological reserves on the gas reservoir material balance curve are the cushion gas volume G of the gas storage reservoir. r(0) , establish a curve for determining the cushion gas volume based on the apparent lower limit pressure of the gas storage reservoir.

[0026] Furthermore, the method of establishing the working gas volume relationship curve for material balance evaluation of the gas storage reservoir in ③ also includes the following method

[0027] S001: Assume that there are multiple upper pressure nodes P of the gas storage max(i) Including the lower limit pressure P of the gas storage min And the lower limit pressure P of the gas storage min Then assume that a certain number of upper pressure nodes P max(i) , where i = 1, 2, ... n, and determine each upper limit pressure node P of the gas storage reservoir max(i) And the corresponding gas storage reservoir's apparent upper limit pressure P max(i) / Z max(i) ~P max(n) / Z max(n) value;

[0028] S002: Use the apparent lower limit pressure of the gas storage to determine the cushion gas volume curve, according to each apparent upper limit pressure P determined max(i) / Z max(i) ~P max(n) / Z max(n) value, determine the apparent upper limit pressure node P of the assumed gas storage max(i) ~P max(n) The corresponding working gas volume G iwork(i) ~G iwork(n) , establish the corresponding relationship curve between gas reservoir material balance curve and working gas volume;

[0029] S003: According to the upper limit pressure node P max(i) ~P max(n) And the determined working gas volume G iwork(i) ~G iwork(n) The value of , where i = 1, 2, ... n, is used to establish the working gas volume relationship curve for material balance evaluation of the gas storage reservoir.

[0030] Furthermore, the method of establishing a working gas volume relationship curve for evaluating the gas injection capacity of a single gas injection well also includes the following method.

[0031] S0001: Assume that there are multiple upper pressure nodes P of a single gas injection well max(j) is the lower limit pressure P of a single gas injection well iminAssuming a certain number of upper pressure nodes P max(j) , where j = 1, 2, ..., n;

[0032] S0002: Select a certain upper pressure node P of the gas injection well in S0001 max(j) According to the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, the upper limit pressure node P is determined. max(j) The corresponding daily gas injection capacity Q inmax , determine the lower limit pressure P of a single gas injection well inmin The upper pressure node P max(n) Multiple formation pressures P (x) The corresponding daily gas injection capacity Q (x) value, then multiple daily gas injection capacity Q (x) Substitute the value into formula (1) to calculate the gas storage at the upper limit pressure node P max(j) The corresponding working gas volume G iwork注(j) ; Formula (1) is as follows

[0033]

[0034] Among them, N in : is the number of gas injection wells determined in step 4, D in : The gas injection time determined in step 4, d; Q inmax : The gas injection capacity corresponding to the upper limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q inmin : The gas injection capacity corresponding to the lower limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q (k) :Q inmin To Q inmax The gas injection capacity corresponding to multiple formation pressure nodes (including Q inmin , Q inmax ), 10 4 m 3 / d; b: for Q inmin To Q inmax Gas injection capacity node Q (k) The number of (including Q inmin , Q inmax ), dimensionless;

[0035] S0003: Based on the upper pressure nodes of multiple gas injection wells assumed in S0001, use the multiple corresponding working gas volumes G calculated in S0002 iwork注(j), establish the working gas volume relationship curve for evaluating the injection capacity of the gas injection wells in the gas storage reservoir.

[0036] Furthermore, the method of establishing a working gas volume relationship curve for evaluating the daily gas production capacity of a single gas production well also includes the following method:

[0037] S00001: Assume that there are multiple upper pressure nodes P of a single gas production well. max(k) is the lower limit pressure P of a single gas well pmin Assuming a certain number of upper pressure nodes P max(k) , where k = 1, 2, ..., n;

[0038] S00002: Select a certain upper pressure node P of a single gas well in S0001 max(k) According to the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, the upper limit pressure node P is determined. max(k) The corresponding daily gas production capacity Q pmax , determine the lower limit pressure P of a single gas well pmin The upper pressure node P max(k) Multiple formation pressures P (y) The corresponding daily gas production capacity Q (y) value, and then multiple daily gas production capacity Q (y) Substitute the value into formula (1) to calculate the gas storage at the upper limit pressure node P max(k) The corresponding working gas volume G iwork采(k) ; Formula (2) is as follows

[0039]

[0040] Among them, N P : The number of gas wells determined in step 5, D P : The gas extraction time determined in step 5, d;

[0041] Q pmax : The gas production capacity corresponding to the upper limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d;

[0042] Q pmin : The gas production capacity corresponding to the lower limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d;Q (x) :Q pmin To Q pmax Gas production capacity nodes corresponding to multiple formation pressures (including Q pmin , Q pmax ), 104 m 3 / d; a: for Q pmin To Q pmax Gas production capacity node Q (x) The number of (including Q pmin , Q pmax ), dimensionless;

[0043] S00003: Based on the upper pressure nodes of multiple gas production wells assumed in S00001, the corresponding working gas volumes G calculated in S00002 are used. iwork采(k) , establish the working gas volume relationship curve for evaluating the gas production capacity of the gas wells in the gas storage reservoir.

[0044] Furthermore, in step 4, the upper limit pressure of the gas storage reservoir when the injection and production balance is determined as P max , P max The intersection curves are constructed for the three curves and an intersection point is generated in each of them. The value of the lowest point in the intersection with the material balance evaluation working gas volume relationship curve is the upper limit pressure P of the gas storage reservoir to be determined when the injection and production balance is reached. max ;

[0045] According to the upper limit pressure P max The corresponding natural gas deviation coefficient Z max , determine the apparent upper limit pressure P of the gas storage reservoir max / Z max The value depends on the upper limit pressure P max / Z max The geological reserves of natural gas corresponding to the value of on the gas reservoir material balance curve are the storage capacity of the gas storage reservoir;

[0046] The working gas volume of the gas storage is the storage capacity of the gas storage and the cushion gas volume G determined in ② r(0) difference.

[0047] The beneficial effects of the present invention are:

[0048] Compared with the prior art, the present invention establishes three curves, namely, a working gas volume relationship curve for evaluating material balance of a gas storage reservoir, a working gas volume relationship curve for evaluating daily gas injection capacity of a gas injection well of a gas storage reservoir, and a working gas volume relationship curve for evaluating daily gas production capacity of a gas production well of a gas storage reservoir. By placing the three curves in the same coordinate system again, an intersection curve is obtained to determine the upper limit pressure of the gas storage reservoir when injection and production are balanced, thereby determining the working gas volume and storage capacity of the gas storage reservoir. The method of the present invention effectively and accurately determines the upper limit pressure of the gas storage reservoir, the working gas volume of the gas storage reservoir, and the storage capacity of the gas storage reservoir, and applies these obtained values ​​to the design, equipment selection, and construction implementation of the gas storage reservoir drilling project, gas production project, ground project, etc. to provide a basis, and can be used to guide the construction types of gas storage reservoirs such as reconstruction of gas storage reservoirs with the current formation pressure being the lower limit pressure, gradually increasing the lower limit pressure gas storage reservoir, and co-construction of gas fields and gas storage reservoirs, optimize the selection of drilling and completion pipes, injection and production wellhead devices, etc. in its drilling project, and the selection of gathering and injection stations, compressors, gas pipelines, etc. in ground projects and the injection and production process flow. The optimized configuration of engineering facilities and storage and peak-shaving capabilities of the gas storage facility during production and operation is achieved, thus avoiding construction waste or restrictions and maximizing economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0050] Figure 1 is the cumulative gas production volume of natural gas in the present invention, G P Schematic diagram of the relationship curve of the corresponding apparent formation pressure P / Z.

[0051] Figure 2 It is a structural schematic diagram of the gas reservoir material balance relationship curve of the present invention.

[0052] Figure 3 This is a schematic diagram of a curve for determining cushion gas volume based on the apparent lower limit pressure of the gas storage reservoir of the present invention.

[0053] Figure 4 It is a schematic diagram of the corresponding relationship curve between the gas reservoir material balance curve and the working gas volume curve of the present invention.

[0054] Figure 5 It is a schematic diagram of the working gas volume relationship curve for evaluating the material balance of the gas storage reservoir of the present invention.

[0055] Figure 6 It is a schematic diagram of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure of the present invention.

[0056] Figure 7 It is a schematic diagram of a relationship curve of multiple daily gas injection capacities corresponding to multiple upper pressure nodes between the lower pressure limit and the upper pressure limit of a single gas injection well of the present invention.

[0057] Figure 8It is a schematic diagram of the working gas volume relationship curve for evaluating the daily gas injection capacity of the gas injection well of the gas storage reservoir of the present invention.

[0058] Fig. 9 It is a schematic diagram of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure of the present invention.

[0059] Fig.10 It is a schematic diagram of a relationship curve of multiple daily gas production capacities corresponding to multiple upper pressure nodes between the lower pressure limit and the upper pressure limit of a single gas production well of the present invention.

[0060] Fig.11 It is a schematic diagram of the working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well of the gas storage reservoir of the present invention.

[0061] Fig.12 It is a schematic diagram of the intersection curve of the present invention. DETAILED DESCRIPTION

[0062] First of all, it should be noted that in each embodiment of the present invention, the following are involved:

[0063] The relationship curve between the geological reserves G of the gas storage facility and the apparent formation pressure P / Z is established. Figure 2 , and establish the cumulative gas production volume G P The corresponding apparent formation pressure P / Z relationship curves belong to the prior art and will not be described in detail in the present invention. For details, please refer to the public document (Natural Gas Engineering [M]. Edited by Li Shilun et al., Petroleum Industry Press, 2008).

[0064] Establish the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, see Figure 6 , and establish the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, see Fig. 9 , all belong to the prior art and will not be described in detail in the present invention. For details, please refer to the public documents (China's Natural Gas Underground Storage [M]. Ma Xinhua, Ding Guosheng, etc., Petroleum Industry Press, 2018) and (Gas Reservoir Type Gas Storage Injection and Production Operation Optimization Technology [M]. Zheng Dewen, Wang Jieming, Ding Guosheng, Li Chun, etc., Petroleum Industry Press, 2018).

[0065] The method for evaluating the working gas volume by determining the lower limit pressure of a gas storage provided by the embodiment of the present invention will be described in detail below through several specific embodiments.

[0066] Embodiment 1:

[0067] Reference Figure 5 , Figure 8 , Fig.11 and Fig.12A method for evaluating the working gas volume by setting a lower limit pressure of a gas storage reservoir comprises the following steps:

[0068] Step 1: Use the material balance method to evaluate the working gas volume and establish the material balance evaluation working gas volume relationship curve of the gas storage reservoir;

[0069] Step 2: Use the gas injection capacity evaluation working gas volume method to establish a daily gas injection capacity evaluation working gas volume relationship curve for the gas injection well;

[0070] Step 3: Use the gas production capacity evaluation working gas volume method to establish a working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well;

[0071] Step 4: Using the three relationship curves in step 1, step 2 and step 3, place the three curves in the same coordinate system to obtain an intersection curve, determine the upper limit pressure of the gas storage when the gas storage is in injection-production balance, and thus determine the working gas volume and storage capacity of the gas storage;

[0072] Step 5: The upper limit pressure of the gas storage, the working gas volume of the gas storage and the storage capacity of the gas storage determined in step 4 are applied to the determination of the construction type of the gas storage and the design and implementation of the gas storage drilling project and ground engineering.

[0073] Embodiment 2:

[0074] Reference Figure 1 , Figure 2 and Figure 5 The material balance evaluation working gas volume method comprises the following steps:

[0075] ①: Establish the gas reservoir material balance relationship curve between the natural gas geological reserves G of the gas storage facility and the apparent formation pressure P / Z, see Figure 2 ;

[0076] ②: Determine the lower limit pressure P of the gas storage min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) ;

[0077] ③: Assume that there are multiple upper limit pressure nodes P of the gas storage max(i) And the corresponding apparent upper limit pressure P max(i) / Z max(i) , using the gas reservoir material balance relationship curve in ①, determine the storage capacity G corresponding to a certain apparent upper limit pressure node of the gas storage reservoir k(i) , by using the storage capacity G corresponding to the apparent upper limit pressure node k(i) and the cushion gas volume G in ② r(0) The difference between the working gas volume G iwork(i)The method is used to obtain each assumed upper limit pressure node P of the gas storage. max(i) The corresponding working gas volume G iwork(i) , and establish the working gas volume relationship curve for gas storage material balance evaluation, see Figure 5 .

[0078] Embodiment 3:

[0079] Reference Figure 6 and Figure 8 Further, the gas injection capacity evaluation working gas volume method comprises the following steps:

[0080] Determine the number of gas injection wells N in and gas injection time D in , determine the lower limit pressure P of a single gas injection well imin , assuming that the gas injection well has multiple upper limit pressure nodes P max(j) ; Establish the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, see Figure 6 ,according to Figure 6 The relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure is used to determine the lower limit pressure P of a single gas injection well. imin The corresponding daily gas injection capacity Q inmin Then select an upper limit pressure node P from the multiple upper limit pressure nodes of the assumed gas injection well. max(j) And determine the corresponding daily gas injection capacity Q inmax(j) , and then determine the lower limit pressure P of the gas injection well inmin and the upper pressure node P max(j) Multiple formation pressures P (x) The corresponding daily gas injection capacity Q (x) The working gas volume G corresponding to the upper limit pressure node of the gas injection well of the gas storage reservoir is obtained by calculation. iwork注(j) ; Then calculate the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) Each assumed upper limit pressure node between and its corresponding working gas volume G iwork注(j) , and draw the relationship curve between each upper limit pressure node of the gas storage injection well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily injection capacity of the gas injection well, see Figure 8 ; The lower limit pressure of a single gas injection well is P inmin The lower limit pressure P of the gas storage min equal;

[0081] The number of gas injection wells N in The number of gas injection wells N in the gas storage facility is determined based on the reservoir distribution scale, gas reservoir development index analysis, and project investment. in ; Gas injection time Din The gas injection time D of the gas storage is determined according to the gas source of the gas storage to be built and the market peak demand. in ; Therefore, the number of gas injection wells N in and gas injection time D in All are known values.

[0082] Embodiment 4:

[0083] Reference Fig. 9 and Fig.11 Further, the gas injection capacity evaluation working gas volume method comprises the following steps:

[0084] Determine the number of gas wells N p and gas sampling time D P , determine the lower limit pressure P of a single gas well pmin , assuming that there are multiple upper limit pressure nodes P of a single gas well max(k) , establish the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, see Fig. 9 ,according to Fig. 9 The relationship curve between the daily gas production capacity of a single gas well and the formation pressure is used to determine the lower limit pressure P of a single gas well. pmin The corresponding daily gas production capacity Q pmin and a certain upper limit pressure node P among multiple upper limit pressure nodes of a single gas production well max(k) The corresponding daily gas production capacity Q pmax(k) Then determine the lower limit pressure P of a single gas well pmin and the upper pressure node P max(k) Multiple formation pressures P (y) The corresponding daily gas injection capacity Q (y) The working gas volume G corresponding to a certain upper limit pressure node of the gas well of the gas storage reservoir is obtained by calculation. iwork采(k) ; Then calculate the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) Each assumed upper limit pressure node and its corresponding working gas volume G iwork采(k) , and draw the relationship curve between each upper limit pressure node of the gas storage reservoir and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily gas production capacity of a single gas well, see Fig.11 ; The lower limit pressure of a single gas well is P pmin The lower limit pressure P of the gas storage min equal;

[0085] The number of gas wells N p The number of gas wells N in the gas storage facility is determined based on the reservoir distribution scale, gas reservoir development index analysis, project investment, and the original gas well utilization plan. p; Gas sampling time D P Determination of the gas storage gas production time D according to the market peak demand of the gas storage to be built P ; Therefore, the number of gas wells N p and gas sampling time D P All are known values.

[0086] Embodiment 5:

[0087] Reference Fig.12 Further, in step 4 and step 5

[0088] Using the material balance evaluation working gas volume relationship curve of the gas storage in step 1, the daily gas injection capacity evaluation working gas volume relationship curve of the gas injection well in step 2, and the daily gas production capacity evaluation working gas volume relationship curve of the gas production well in step 3, the three curves are placed in the same coordinate system to obtain an intersection curve, see Fig.12 , determine the upper limit pressure P of the gas storage when the gas storage is balanced between injection and production max , thereby determining the working gas volume and storage capacity of the gas storage;

[0089] According to the upper limit pressure P of the gas storage determined above max The determined working gas volume and storage capacity of the gas storage are used to determine the construction type of the gas storage and the design and implementation of the gas storage drilling project and ground engineering.

[0090] The above method can effectively and accurately determine the upper pressure limit of the gas storage, the working gas volume of the gas storage, and the storage capacity of the gas storage. These values ​​can be used to provide a basis for the design, equipment selection, and construction implementation of the gas storage drilling project, gas production project, and ground project. It can be used to guide the construction of gas storages such as the reconstruction of gas storages with the current formation pressure being the lower pressure limit, the gradual increase of the lower pressure limit gas storage, and the co-construction of gas fields and gas storages, and optimize the selection of drilling and completion pipes, injection and production wellhead devices, etc. in the drilling project, and the selection of the gathering and injection stations, compressors, gas pipelines, etc. in the ground project and the injection and production process. The optimal configuration of the engineering facilities and the storage and peak-shaving capacity of the gas storage in the production operation of the gas storage is realized, which avoids construction waste or restrictions and maximizes economic benefits.

[0091] Embodiment 6:

[0092] A method for evaluating working gas volume by setting a lower limit pressure of a gas storage reservoir comprises the following steps

[0093] ①: Establish the gas reservoir material balance relationship curve between the natural gas geological reserves G of the gas storage and the apparent formation pressure P / Z, including the following methods:

[0094] S1: Obtain the cumulative geological gas production of natural gas in the gas storage facility G p, formation pressure P and the natural gas deviation coefficient Z corresponding to the formation pressure P, determine the apparent formation pressure as the ratio of the formation pressure P to the natural gas deviation coefficient Z corresponding to it = P / Z, and establish the natural gas geological cumulative gas production G P The corresponding apparent formation pressure P / Z relationship curve is shown in Figure 1 At this time, when the apparent formation pressure P / Z = 0, the corresponding cumulative natural gas geological production G P = Natural gas geological reserves G;

[0095] S2: Obtain the original formation pressure P of the gas reservoir in the reconstructed gas storage facility i and its corresponding natural gas deviation coefficient Z i , the original apparent formation pressure before gas reservoir development is determined as the original formation pressure P i Its original formation pressure P i The corresponding natural gas deviation coefficient Z i The ratio of = P i / Z i , according to the original apparent formation pressure P i / Z i The relationship between the natural gas geological reserves G in step S1 is used to establish the gas reservoir material balance relationship curve, see Figure 2 ;

[0096] ②: Determine the lower limit pressure P of the gas storage min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) , and also includes the following methods

[0097] S01: The current formation pressure or the specified formation pressure is determined as the lower limit pressure P of the gas storage reservoir. min ;

[0098] S02: Lower limit pressure P of gas storage min The corresponding natural gas deviation coefficient is Z min , determine the lower limit pressure P of the gas storage min The corresponding natural gas deviation coefficient Z mi The ratio is the apparent lower limit formation pressure P of the gas storage reservoir. min / Z min ;

[0099] S03: Based on the determined apparent lower limit formation pressure P of the gas storage reservoir min / Z min The corresponding natural gas geological reserves on the gas reservoir material balance curve are the cushion gas volume G of the gas storage reservoir. r(0) , establish a curve for determining the cushion gas volume based on the apparent lower limit pressure of the gas storage reservoir, see Figure 3 ;

[0100] ③: Assume that there are multiple upper limit pressure nodes P of the gas storage max(i) And the corresponding apparent upper limit pressure P max(i) / Z max(i) , using the gas reservoir material balance relationship curve in ①, determine the storage capacity G corresponding to a certain apparent upper limit pressure node of the gas storage reservoir k(i) , by using the storage capacity G corresponding to the apparent upper limit pressure node k(i) and the cushion gas volume G in ② r(0) The difference between the working gas volume G iwork(i) The method is used to obtain each assumed upper limit pressure node P of the gas storage. max(i) The corresponding working gas volume G iwork(i) , and establish the working gas volume relationship curve for material balance evaluation of gas storage, including the following methods

[0101] S001: Assume that there are multiple upper pressure nodes P of the gas storage max(i) Including the lower limit pressure P of the gas storage min And the lower limit pressure P of the gas storage min Then assume that a certain number of upper pressure nodes P max(i) , where i = 1, 2, ... n, and determine each upper limit pressure node P of the gas storage reservoir max(i) And the corresponding gas storage reservoir's apparent upper limit pressure P max(i) / Z max(i) ~P max(n) / Z max(n) value;

[0102] S002: Use the apparent lower limit pressure of the gas storage to determine the cushion gas volume curve, according to each apparent upper limit pressure P determined max(i) / Z max(i) ~P max(n) / Z max(n) value, determine each upper limit pressure node P of the assumed gas storage max(i) ~P max(n) The corresponding working gas volume G iwork(i) ~G iwork(n) , establish the relationship curve between gas reservoir material balance curve and working gas volume, see Figure 4 ;

[0103] S003: According to the upper limit pressure P max(i) ~P max(n) And the determined working gas volume G iwork(i) ~G iwork(n) The value of i = 1, 2, ... n is used to establish the working gas volume relationship curve for material balance evaluation of gas storage, see Figure 5 .

[0104] Establishing the working gas volume relationship curve of the gas storage material balance evaluation also includes obtaining each upper limit pressure node P of the gas storage by calculation. max(i) ~P max(n) The corresponding working gas volume G iwork(i) ~G iwork(n) ; Includes the following methods

[0105] ① Using each apparent upper limit pressure P of the gas storage in step S001 max(i) / Z max(i) ~P max(n) / Z max(n) The working gas volume G corresponding to each upper limit pressure node of the gas storage is calculated by formula (3). iwork(i) ;

[0106] G iwork(i) =G×(P max(i) / Z max(i) -P min / Z min ) / (P i / Z i ) Formula (3)

[0107] Among them, G iwork(i) : is the working gas volume corresponding to a certain upper limit pressure node of the gas storage in step S001, 10 8 m 3 ; G: natural gas geological reserves of gas storage, 10 8 m 3 ;P max(i) : is the upper limit pressure of the gas storage, MPa; Z max(i) : is the natural gas deviation coefficient under the upper limit pressure condition of the gas storage, dimensionless; P min : is the lower limit pressure of the gas storage, MPa; Z min : is the natural gas deviation coefficient under the lower limit pressure condition of the gas storage, dimensionless; P i : original geological formation pressure of natural gas in the gas storage, MPa; Z i : natural gas deviation coefficient under the natural gas geological original formation pressure conditions of the gas storage, dimensionless;

[0108] ②Use the method in step S002 to obtain each assumed upper limit pressure node P of the gas storage in step S001 max(i) The corresponding working gas volume G iwork(i) , establish the working gas volume relationship curve for material balance evaluation of gas storage, see Figure 5 .

[0109] The values ​​calculated by this method are more accurate, so the working gas volume relationship curve of the gas storage material balance evaluation established by it is shown in Figure 2. Figure 5 More accurate, laying the foundation for later determination of the accurate upper limit pressure of the gas storage reservoir.

[0110] The gas injection capacity evaluation working gas volume method comprises the following steps:

[0111] Determine the number of gas injection wells N in and gas injection time D in , determine the lower limit pressure P of a single gas injection well imin , assuming that the gas injection well has multiple upper limit pressure nodes P max(j) ; Establish the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, see Figure 6 , determine the lower limit pressure P of a single gas injection well imin The corresponding daily gas injection capacity Q inmin and select an upper limit pressure node P from multiple upper limit pressure nodes of a single gas injection well max(j) The corresponding daily gas injection capacity Q inmax(j) , and then determine the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) The daily gas injection capacity Q corresponding to the multiple formation pressure nodes between (k) , the working gas volume G corresponding to a certain upper limit pressure node of the gas injection well of the gas storage reservoir is obtained by calculation iwork注(j) ; Then calculate the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) Each assumed upper limit pressure node between and its corresponding working gas volume G iwork注(j) , and draw the relationship curve between each upper limit pressure node of the gas storage injection well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the injection capacity of a single gas injection well, see Figure 8 ;

[0112] Establishing the gas injection capacity evaluation working gas volume relationship curve of a single gas injection well, including the following methods

[0113] S0001: Assume that there are multiple upper pressure nodes P of a single gas injection well max(j) is the lower limit pressure P of a single gas injection well imin Assuming a certain number of upper pressure nodes P max(j) , where j = 1, 2, ..., n;

[0114] S0002: Select a certain upper pressure node P of the gas injection well in S0001 max(j) According to the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, the upper limit pressure node P is determined. max(j) The corresponding daily gas injection capacity Q inmax, determine the lower limit pressure P of a single gas injection well inmin The upper pressure node P max(n) Multiple formation pressures P (x) The corresponding daily gas injection capacity Q (x) Value, see Figure 7 , Figure 7 It is based on the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, see Figure 6 , establish the lower limit pressure P of a single gas injection well imin and the upper pressure node P max(n) Multiple upper pressure nodes P max(j) The corresponding daily gas injection capacity Q (k) The relationship curve of Figure 7 , and then multiple daily gas injection capacity Q (x) Substitute the value into formula (1) to calculate the gas storage at the upper limit pressure node P max(j) The corresponding working gas volume G iwork注(j) ; Formula (1) is as follows

[0115]

[0116] Among them, N in : is the number of gas injection wells determined in step 4, D in : The gas injection time determined in step 4, d; Q inmax : The gas injection capacity corresponding to the upper limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q inmin : The gas injection capacity corresponding to the lower limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q (k) :Q inmin To Q inmax The gas injection capacity corresponding to multiple formation pressure nodes (including Q inmin , Q inmax ), 10 4 m 3 / d; b: for Q inmin To Q inmax Gas injection capacity node Q (k) The number of (including Q inmin , Q inmax ), dimensionless;

[0117] S0003: Based on the upper pressure nodes of multiple gas injection wells assumed in S0001, use the multiple corresponding working gas volumes G calculated in S0002 iwork注(j), establish the gas injection capacity evaluation working gas volume relationship curve of the gas storage injection well, see Figure 8 ;

[0118] The gas production capacity evaluation working gas volume method comprises the following steps:

[0119] Determine the number of gas wells N p and gas sampling time D P , determine the lower limit pressure P of a single gas well pmin , assuming that there are multiple upper limit pressure nodes P of a single gas well max(k) , establish the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, see Fig. 9 , determine the lower limit pressure P of a single gas well pmin The corresponding daily gas production capacity Q pmin and a certain upper limit pressure node P among multiple upper limit pressure nodes of a single gas production well max(k) The corresponding daily gas production capacity Q pmax(k) Then determine the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) The daily gas injection capacity Q corresponding to the multiple formation pressure nodes between (x) , the working gas volume G corresponding to a certain upper limit pressure node of the gas well of the gas storage reservoir is obtained by calculation iwork采(k) ; Then calculate the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) Each assumed upper limit pressure node and its corresponding working gas volume G iwork采(k) , and draw the relationship curve between each upper limit pressure node of the gas storage reservoir and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily gas production capacity of the gas well, see Fig.11 ;

[0120] The following methods are also included to establish the working gas volume relationship curve for evaluating the daily gas production capacity of a single gas well:

[0121] S00001: Assume that there are multiple upper pressure nodes P of a single gas production well. max(k) is the pressure node above the lower limit pressure Ppmin of a single gas well. Assuming a certain number of upper limit pressure nodes P max(k) , where k = 1, 2, ..., n;

[0122] S00002: Select a certain upper pressure node P of a single gas well in S0001 max(k) According to the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, see Fig. 9 , determine the upper limit pressure node P max(k) The corresponding daily gas production capacity Qpmax , determine the lower limit pressure P of a single gas well pmin The upper pressure node P max(k) Multiple formation pressures P (y) The corresponding daily gas production capacity Q (y) Value, see Fig.10 , Fig.10 According to the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, see Fig. 9 , establish the lower limit pressure P of a single gas well pmin and the upper pressure node P max(n) Multiple upper pressure nodes P max(k) The corresponding daily gas production capacity Q (X) The relationship curve of Fig.10 , and then multiple daily gas production capacities Q (x) Substitute the value into formula (2) to calculate multiple upper limit pressure nodes P max(k) The corresponding multiple working gas volumes G iwork采(k) ; Formula (2) is as follows

[0123]

[0124] Among them, N P : The number of gas wells determined in step 5, D P : The gas extraction time determined in step 5, d;

[0125] Q pmax : The gas production capacity corresponding to the upper limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d;

[0126] Q pmin : The gas production capacity corresponding to the lower limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d;Q (x) :Q pmin To Q pmax Gas production capacity nodes corresponding to multiple formation pressures (including Q pmin , Q pmax ), 10 4 m 3 / d; a: for Q pmin To Q pmax Gas production capacity node Q (x) The number of (including Q pmin , Q pmax ), dimensionless;

[0127] S00003: Based on the upper pressure nodes of multiple gas production wells assumed in S00001, the corresponding working gas volumes G calculated in S00002 are used. iwork采(k) , establish the gas production capacity evaluation working gas volume relationship curve of the gas storage reservoir gas well, see Fig.11 .

[0128] Step 4: Using the material balance evaluation working gas volume relationship curve of the gas storage reservoir in step 1, the gas injection capacity evaluation working gas volume relationship curve of the gas injection well in step 2, and the daily gas production capacity evaluation working gas volume relationship curve of the gas production well in step 3, place the three curves in the same coordinate system to obtain an intersection curve, see Fig.12 , determine the upper limit pressure P of the gas storage when the gas storage is balanced between injection and production max , thereby determining the working gas volume and storage capacity of the gas storage; it also includes the following methods

[0129] The determination of the upper limit pressure P of the gas storage reservoir when the gas storage reservoir is balanced with injection and production max The intersection curves are constructed for the three curves and an intersection point is generated in each of them. The value of the lowest point in the intersection with the material balance evaluation working gas volume relationship curve is the upper limit pressure P of the gas storage reservoir to be determined when the injection and production balance is reached. max ;

[0130] According to the upper limit pressure P max The corresponding natural gas deviation coefficient Z max , determine the apparent upper limit pressure P of the gas storage reservoir max / Z max The value depends on the upper limit pressure P max / Z max The geological reserves of natural gas corresponding to the value of on the gas reservoir material balance curve are the storage capacity of the gas storage reservoir;

[0131] The working gas volume of the gas storage is the storage capacity of the gas storage and the cushion gas volume G determined in ② r(0) difference.

[0132] Step 5: According to the upper limit pressure P of the gas storage determined in step 6 max The determined working gas volume and storage capacity of the gas storage are used to determine the construction type of the gas storage and the design and implementation of the gas storage drilling project and ground engineering.

[0133] The above method can further accurately determine the upper limit pressure, storage capacity and working gas volume of the gas storage when the gas storage is in injection-production balance, and realize the optimal configuration of the engineering facilities and the storage and peak-shaving capacity of the gas storage during production operation, avoid construction waste or restrictions, and maximize economic benefits.

[0134] The method of the present invention evaluates the upper limit pressure, working gas volume, storage capacity and other indicators under the conditions of limited well number, injection and production time, lower limit pressure and remaining reserves to achieve the injection and production balance of the gas storage reservoir, meeting the evaluation index requirements for the above special circumstances.

[0135] The above is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Within the knowledge scope of ordinary technicians in the field, various changes can be made without departing from the purpose of the present invention, which are all within the protection scope of this technology.

[0136] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0137] The technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for evaluating the working gas volume by setting a lower limit pressure of a gas storage, characterized by: Includes the following step Step 1: Use the material balance method to evaluate the working gas volume and establish the material balance evaluation working gas volume relationship curve of the gas storage reservoir; Among them, the material balance evaluation working gas method includes the following steps ①: Establish the gas reservoir material balance relationship curve between the natural gas geological reserves G of the gas storage and the apparent formation pressure P / Z; ②: Determine the lower limit pressure P of the gas storage min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) ; ③: Assume that there are multiple upper limit pressure nodes P of the gas storage max(i) And the corresponding apparent upper limit pressure P max(i) / Z max(i) , using the gas reservoir material balance relationship curve in ①, determine the storage capacity G corresponding to a certain apparent upper limit pressure node of the gas storage reservoir k(i) , by using the storage capacity G corresponding to the apparent upper limit pressure node k(i) and the cushion gas volume G in ② r(0) The difference between the upper and lower limits of each assumed upper pressure node P of the gas storage is obtained. max(i) The corresponding working gas volume G iwork(i) , and establish the working gas volume relationship curve for material balance evaluation of gas storage; Step 2: Use the gas injection capacity evaluation working gas volume method to establish a daily gas injection capacity evaluation working gas volume relationship curve for the gas injection well; Step 3: Use the gas production capacity evaluation working gas volume method to establish a working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well; Step 4: Place the three relationship curves in step 1, step 2 and step 3 in the same coordinate system to obtain the intersection curve, and determine the upper limit pressure of the gas storage reservoir at the injection-production balance as P max , P max The intersection curves are constructed for the three curves and an intersection point is generated in each of them. The value of the lowest point in the intersection with the material balance evaluation working gas volume relationship curve is the upper limit pressure P of the gas storage reservoir to be determined when the injection and production balance is reached. max ; According to the upper limit pressure P max The corresponding natural gas deviation coefficient Z max , determine the apparent upper limit pressure P of the gas storage reservoir max / Z max The value depends on the upper limit pressure P max / Z max The geological reserves of natural gas corresponding to the value of on the gas reservoir material balance curve are the storage capacity of the gas storage reservoir; The working gas volume of the gas storage is the storage capacity of the gas storage and the cushion gas volume G determined in ② r(0) difference; Step 5: The upper limit pressure of the gas storage, the working gas volume of the gas storage and the storage capacity of the gas storage determined in step 4 are applied to the determination of the construction type of the gas storage and the design and implementation of the gas storage drilling project and ground engineering.

2. The method for evaluating the working gas volume by setting a lower limit pressure of a gas storage according to claim 1 is characterized by: The gas injection capacity evaluation working gas volume method comprises the following steps: Determine the number of gas injection wells N in and gas injection time D in , determine the lower limit pressure P of a single gas injection well inmin , assuming that the gas injection well has multiple upper limit pressure nodes P max(j) ; Establish the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, and determine the lower limit pressure P of a single gas injection well inmin The corresponding daily gas injection capacity Q inmin and select an upper limit pressure node P from multiple upper limit pressure nodes of a single gas injection well max(j) The corresponding daily gas injection capacity Q inmax(j) , and then determine the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) The daily gas injection capacity Q corresponding to the multiple formation pressure nodes between (x) , the working gas volume G corresponding to a certain upper limit pressure node of the gas injection well of the gas storage reservoir is obtained by calculation iwork注(j) ; Then calculate the lower limit pressure P of the gas injection well inmin and a certain upper pressure node P max(j) Each assumed upper limit pressure node between and its corresponding working gas volume G iwork注(j) , and draw the relationship curve between each upper limit pressure node of the gas storage reservoir injection well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily injection capacity of the gas injection well.

3. The method for evaluating the working gas volume of a gas storage by setting a lower limit pressure according to claim 1 is characterized by: The gas production capacity evaluation working gas volume method comprises the following steps: Determine the number of gas wells N p Gas sampling time D P , determine the lower limit pressure P of a single gas well pmin , assuming that there are multiple upper limit pressure nodes P of a single gas well max(k) , establish the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, and determine the lower limit pressure P of a single gas well pmin The corresponding daily gas production capacity Q pmin and a certain upper limit pressure node P among multiple upper limit pressure nodes of a single gas production well max(k) The corresponding daily gas production capacity Q pmax(k) Then determine the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) The daily gas production capacity Q corresponding to the multiple formation pressure nodes between (y) , the working gas volume G corresponding to a certain upper limit pressure node of the gas well of the gas storage reservoir is obtained by calculation iwork采(k) ; Then calculate the lower limit pressure P of a single gas well pmin and a certain upper pressure node P max(k) Each assumed upper limit pressure node and its corresponding working gas volume G iwork采(k) , and draw the relationship curve between each upper limit pressure node of the gas storage reservoir's gas production well and the corresponding working gas volume, that is, establish the working gas volume relationship curve for evaluating the daily gas production capacity of the gas production well.

4. The method for evaluating the working gas volume by setting a lower limit pressure of a gas storage according to claim 1 is characterized by: The material balance relationship curve of the natural gas geological reserves G and the apparent formation pressure P / Z of the gas storage in the above-mentioned ① also includes the following method S1: Obtain the cumulative geological gas production of natural gas in the gas storage facility G p , formation pressure P and the natural gas deviation coefficient Z corresponding to the formation pressure P, determine the apparent formation pressure as the ratio of the formation pressure P to the natural gas deviation coefficient Z corresponding to it = P / Z, and establish the natural gas geological cumulative gas production G P The relationship curve of the apparent formation pressure P / Z corresponding to it. When the apparent formation pressure P / Z = 0, the corresponding cumulative gas production volume of natural gas is G P = Natural gas geological reserves G; S2: Obtain the original formation pressure P of the gas reservoir of the reconstructed gas storage facility i and its corresponding natural gas deviation coefficient Z i , the original apparent formation pressure before gas reservoir development is determined as the original formation pressure P i Its original formation pressure P i The corresponding natural gas deviation coefficient Z i The ratio of = P i / Z i , according to the original apparent formation pressure P i / Z i The relationship between the gas geological reserves G in step S1 is used to establish a gas reservoir material balance relationship curve.

5. The method for evaluating the working gas volume by setting a lower limit pressure of a gas storage according to claim 1 is characterized by: The lower limit pressure P of the gas storage is determined in ② min And the corresponding apparent lower limit pressure P min / Z min , and use the gas reservoir material balance relationship curve in ① to determine the corresponding cushion gas volume G r(0) Includes the following methods S01: The current formation pressure or the specified formation pressure is determined as the lower limit pressure P of the gas storage reservoir. min ; S02: Lower limit pressure P of gas storage min The corresponding natural gas deviation coefficient is Z min , determine the lower limit pressure P of the gas storage min The corresponding natural gas deviation coefficient Z mi The ratio is the apparent lower limit formation pressure P of the gas storage reservoir. min / Z min ; S03: Based on the determined apparent lower limit formation pressure P of the gas storage reservoir min / Z min The corresponding natural gas geological reserves on the gas reservoir material balance curve are the cushion gas volume G of the gas storage reservoir. r(0) , establish a curve for determining the cushion gas volume based on the apparent lower limit pressure of the gas storage reservoir.

6. The method for evaluating the working gas volume by setting a lower limit pressure of a gas storage according to claim 1 is characterized by: The method of establishing the working gas volume relationship curve for material balance evaluation of gas storage in ③ also includes the following methods S001: Assume that there are multiple upper pressure nodes P of the gas storage max(i) Including the lower limit pressure P of the gas storage min And the lower limit pressure P of the gas storage min The upper pressure node above, then assume that the upper pressure node P max(i) , where i = 1, 2, ... n, and determine each upper limit pressure node P of the gas storage reservoir max(i) And the corresponding gas storage reservoir's apparent upper limit pressure P max(i) / Z max(i) ~P max(n) / Z max(n) value; S002: Use the apparent lower limit pressure of the gas storage to determine the cushion gas volume curve, according to each apparent upper limit pressure P determined max(i) / Z max(i) ~P max(n) / Z max(n) value, determine the apparent upper limit pressure node P of the assumed gas storage max(i) ~P max(n) The corresponding working gas volume G iwork(i) ~G iwork(n) , establish the corresponding relationship curve between gas reservoir material balance curve and working gas volume; S003: According to the upper limit pressure node P max(i) ~P max(n) And the determined working gas volume G iwork(i) ~G iwork(n) The value of , where i = 1, 2, ... n, is used to establish the working gas volume relationship curve for material balance evaluation of the gas storage reservoir.

7. The method for evaluating the working gas volume by setting a lower limit pressure of a gas storage according to claim 2 is characterized by: The method of establishing the gas injection capacity evaluation working gas volume relationship curve of a single gas injection well also includes the following method: S0001: Assume that there are multiple upper pressure nodes P of a single gas injection well max(j) is the lower limit pressure P of a single gas injection well inmin Assume that the upper pressure node P max(j) , where j = 1, 2, ..., n; S0002: Select a certain upper pressure node P of the gas injection well in S0001 max(j) According to the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, the upper limit pressure node P is determined. max(j) The corresponding daily gas injection capacity Q inmax , determine the lower limit pressure P of a single gas injection well inmin The upper pressure node P max(n) Multiple formation pressures P (x) The corresponding daily gas injection capacity Q (x) value, then multiple daily gas injection capacity Q (x) Substitute the value into formula (1) to calculate the gas storage at the upper limit pressure node P max(j) The corresponding working gas volume G iwork注(j) ; Formula (1) is as follows Among them, N in : is the number of gas injection wells, D in : is the gas injection time, d; Q inmax : The gas injection capacity corresponding to the upper limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q inmin : The gas injection capacity corresponding to the lower limit pressure of the relationship curve between the daily gas injection capacity of a single gas injection well and the formation pressure, 10 4 m 3 / d;Q (k) :Q inmin To Q inmax The gas injection capacity corresponding to multiple formation pressure nodes between inmin , Q inmax , 10 4 m 3 / d; b: for Q inmin To Q inmax Gas injection capacity node Q (k) The number of inmin , Q inmax , dimensionless; S0003: Based on the upper pressure nodes of multiple gas injection wells assumed in S0001, use the multiple corresponding working gas volumes G calculated in S0002 iwork注(j) , establish the working gas volume relationship curve for evaluating the injection capacity of the gas injection wells in the gas storage reservoir.

8. The method for evaluating the working gas volume by determining the lower limit pressure of a gas storage according to claim 3 is characterized by: The method of establishing the working gas volume relationship curve for evaluating the daily gas production capacity of a single gas production well also includes the following method: S00001: Assume that there are multiple upper pressure nodes P of a single gas production well. max(k) is the lower limit pressure of a single gas well P pmin Assume that the upper pressure node P max(k) , where k = 1, 2, ..., n; S00002: Select a certain upper pressure node P of a single gas well in S0001 max(k) According to the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, the upper limit pressure node P is determined. max(k) The corresponding daily gas production capacity Q pmax , determine the lower limit pressure P of a single gas well pmin The upper pressure node P max(k) Multiple formation pressures P (y) The corresponding daily gas production capacity Q (y) value, and then multiple daily gas production capacity Q (y) Substitute the value into formula (1) to calculate the gas storage at the upper limit pressure node P max(k) The corresponding working gas volume G iwork采(k) ; Formula (2) is as follows Among them, N P : is the number of gas wells, D P : is the gas sampling time, d; Q pmax : The gas production capacity corresponding to the upper limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d; Q pmin : The gas production capacity corresponding to the lower limit pressure of the relationship curve between the daily gas production capacity of a single gas well and the formation pressure, 10 4 m 3 / d;Q (x) :Q pmin To Q pmax The gas production capacity nodes corresponding to multiple formation pressures between pmin , Q pmax , 10 4 m 3 / d; a: for Q pmin To Q pmax Gas production capacity node Q (x) The number of, including Q pmin , Q pmax , dimensionless; S00003: Based on the upper pressure nodes of multiple gas production wells assumed in S00001, the corresponding working gas volumes G calculated in S00002 are used. iwork采(k) , establish the working gas volume relationship curve for evaluating the gas production capacity of the gas wells in the gas storage reservoir.

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