Method for predicting depth of gas-liquid interface for gas injection and brine discharge and related equipment

Abstract

The invention discloses a gas injection and brine discharge gas-liquid interface depth prediction method and related equipment, and relates to the technical field of salt cavern gas injection and brine discharge, and the method comprises the following steps: obtaining a gas density function in a gas injection well, a first wellhead pressure of the gas injection well and a brine liquid column pressure, the gas density function represents the corresponding relation between the gas column pressure of the gas injection well and the formation temperature, and the brine liquid column pressure represents the corresponding relation between the brine pressure gradient and the second wellhead pressure of the brine discharge well; based on the gas density function and the first wellhead pressure, a gas column pressure function is determined, and the gas column pressure function is used for representing the corresponding relation among the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth; based on a pressure balance method, the gas column pressure function and the brine liquid column pressure, a gas-liquid interface depth function in the gas injection well is determined; and inputting the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure into the gas-liquid interface depth function to obtain the gas-liquid interface depth.

Description

Technical Field

[0001] The present application relates to the technical field of gas injection and brine removal in salt caverns, and in particular to a method for predicting the depth of a gas-liquid interface during gas injection and brine removal and related equipment. Background Art

[0002] At present, salt caverns are widely regarded as ideal for storing natural gas, hydrogen and compressed air due to their excellent sealing performance, structural stability and adaptability to high-pressure conditions. In the gas storage process, a key step is to discharge the brine produced by the salt cavern by injecting high-pressure gas. In the process of gas injection and brine discharge, the position of the gas-liquid interface is a key parameter reflecting the progress and stability of the operation. Since a significant rise in the gas-liquid interface may threaten the structural integrity of the salt cavern, accurate monitoring of the gas-liquid interface depth is crucial to assessing the safety of the salt cavern.

[0003] However, in engineering practice, monitoring the gas-liquid interface has always been a major challenge. Although some studies have proposed solutions to improve measuring instruments, such as using methods such as acoustic wave velocity measurement to monitor the depth of the gas-liquid interface, these technologies have not been widely promoted in practical applications due to the huge consumption of human and material resources. Therefore, it is necessary to propose a prediction method for the depth of the gas-liquid interface in gas injection and brine removal to at least solve some of the above problems. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In a first aspect, an embodiment of the present application provides a method for predicting the depth of a gas-liquid interface during gas injection and brine removal, the method comprising:

[0006] Obtaining a gas density function in a gas injection well, a first wellhead pressure of the gas injection well, and a brine column pressure, wherein the gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature, and the brine column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well;

[0007] Based on the gas density function and the first wellhead pressure, a gas column pressure function is determined, wherein the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth;

[0008] Determining a gas-liquid interface depth function in a gas injection well based on a pressure balance method, the gas column pressure function and the brine liquid column pressure;

[0009] The first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure are input into the gas-liquid interface depth function to obtain the gas-liquid interface depth.

[0010] In one embodiment of the present invention, determining the gas column pressure function based on the gas density function and the first wellhead pressure includes:

[0011] determining an initial gas column pressure function based on the gas density function and the first wellhead pressure;

[0012] Based on the derivation algorithm, the integration algorithm and the solution algorithm, the initial air column pressure function is converted to obtain the air column pressure function.

[0013] In one embodiment of the present invention, the initial gas column pressure function is determined based on the gas density function and the first wellhead pressure, and is calculated by the following formula:

[0014]

[0015] Where g is the gravitational acceleration, P(0) is the first wellhead pressure of the gas injection well, h is the gas-liquid interface depth, and ρ(h) is the gas density when the gas-liquid interface depth is h.

[0016] In one embodiment of the present invention, based on a derivation algorithm, an integration algorithm and a solution algorithm, the initial gas column pressure function is converted to obtain a gas column pressure function, including:

[0017] The initial air column pressure function is derived to obtain a first air column pressure function, where the first air column pressure function is calculated using the following formula:

[0018] P ′ (h) = ρ(h)g;

[0019] Where ρ(h) is the gas density when the gas-liquid interface depth is h, and g is the gravitational acceleration;

[0020] The first air column pressure function is integrated to obtain a second air column pressure function, where the second air column pressure function is calculated using the following formula:

[0021]

[0022] Among them, T w is the wellhead temperature, K is a constant, and h is the depth of the gas-liquid interface;

[0023] The second air column pressure function is solved and calculated to obtain a third air column pressure function, and the third air column pressure function is calculated by the following formula:

[0024]

[0025] Where C is the integration constant, T w is the wellhead temperature, K is a constant;

[0026] An air column pressure function is determined based on the third air column pressure function.

[0027] In one embodiment of the present invention, the gas column pressure function is determined based on the gas density function and the first wellhead pressure, and is calculated by the following formula:

[0028]

[0029] Where P(0) is the first wellhead pressure of the gas injection well, T w is the wellhead temperature and K is a constant.

[0030] In one embodiment of the present invention, the brine liquid column pressure is obtained by:

[0031] Obtaining the brine pressure gradient and the second wellhead pressure of the brine drainage well;

[0032] Multiplying the brine pressure gradient by the gas-liquid interface depth to obtain a second parameter;

[0033] The second parameter and the second wellhead pressure are summed to obtain the brine liquid column pressure.

[0034] In one embodiment of the present invention, the gas-liquid interface depth function in the gas injection well is determined based on the pressure balance method, the gas column pressure function and the brine liquid column pressure, and is calculated by the following formula:

[0035]

[0036] Among them, T w is the wellhead temperature, K is a constant, γ b is the pressure gradient of brine, P′ w is the second wellhead pressure of the brine drainage well, and h is the depth of the gas-liquid interface.

[0037] In a second aspect, the present application proposes a prediction system for the depth of the gas-liquid interface of gas injection and brine removal, the system comprising: a data acquisition module, a first calculation module and a second calculation module;

[0038] The data acquisition module is configured to: acquire a gas density function in the gas injection well, a first wellhead pressure of the gas injection well, and a brine column pressure, wherein the gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature, and the brine column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well;

[0039] The first calculation module is configured to: determine the gas column pressure function based on the gas density function and the first wellhead pressure, and the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth; the second calculation module is configured to: determine the gas-liquid interface depth function in the gas injection well based on the pressure balance method, the gas column pressure and the brine liquid column pressure; input the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure into the gas-liquid interface depth function to obtain gas-liquid interface depth data.

[0040] In a third aspect, an electronic device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is used to implement the steps of a method for predicting the depth of a gas-liquid interface for gas injection and brine removal as described in any one of the first aspects above when executing the computer program stored in the memory.

[0041] In a fourth aspect, the present application further proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for predicting the depth of a gas-liquid interface for gas injection and brine removal according to any one of the first aspects.

[0042] In summary, the prediction method of the gas-liquid interface depth of the gas injection and brine drainage in the embodiment of the present application can calculate the gas-liquid interface depth data through known parameters such as the gas density in the gas injection well, the first wellhead pressure of the gas injection well, the pressure gradient of the brine, and the second wellhead pressure of the brine drainage well. The calculation method is efficient and fast, and can achieve real-time monitoring, which greatly saves manpower and material resources.

[0043] The method for predicting the depth of the gas-liquid interface for gas injection and brine removal proposed in this application, and other advantages, objectives and features of this application will be partially reflected through the following description, and will also be partially understood by technical personnel in this field through research and practice of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present specification. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0045] Figure 1 A schematic diagram of the process of predicting the depth of the gas-liquid interface for gas injection and brine removal provided in an embodiment of the present application;

[0046] Figure 2 A schematic diagram of the structure of a prediction system for the depth of the gas-liquid interface for gas injection and brine removal provided in an embodiment of the present application;

[0047] Figure 3 A schematic diagram of the structure of an electronic device for predicting the depth of the gas-liquid interface for gas injection and brine removal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification are described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0049] In this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The term "more than two" includes two or more than two situations.

[0050] See also Figure 1 , which is a schematic flow diagram of a method for predicting the depth of the gas-liquid interface during gas injection and brine removal provided in an embodiment of the present application, which may specifically include:

[0051] S110. Obtain the gas density function in the gas injection well, the first wellhead pressure of the gas injection well, and the brine liquid column pressure. The gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature. The brine liquid column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well.

[0052] Exemplarily, the gas density function in the gas injection well, the first wellhead pressure of the gas injection well, and the brine column pressure are obtained. The gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature. Specifically, the temperature and pressure at different depths are different, and the density of the gas will be affected by the two. According to the ideal gas state equation, the gas density at different depths is shown in formula (1).

[0053]

[0054] Where ρ(h) is the gas density at depth h, in kg / m 3 ; P(h) is the gas column pressure at a depth of h, in Pa; T(h) is the formation temperature at a depth of h, in K; ρ0 is the gas density under standard conditions, in m; P0 is 101325 Pa (i.e. 1 atm); T0 is 273.15 K (i.e. 0°C); h is the depth, in m.

[0055] The formation temperatures at different depths are:

[0056] T(h)=T w +0.03h (2);

[0057] Among them, T w is the wellhead temperature, unit K.

[0058] The first wellhead pressure of the gas injection well is the pressure value at the wellhead of the gas injection well. It reflects the pressure conditions in the gas injection well and is very important for evaluating the working status and safety of the gas injection well. The brine liquid column pressure is used to characterize the correspondence between the brine pressure gradient and the second wellhead pressure of the brine drainage well. The second wellhead pressure of the brine drainage well is the pressure value at the wellhead of the brine drainage well. Through the correspondence between the brine pressure gradient and the second wellhead pressure, the pressure of the brine at different depths can be determined, thereby evaluating the working status of the brine drainage well and the safety of brine discharge.

[0059] S120. Determine a gas column pressure function based on the gas density function and the first wellhead pressure, wherein the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth.

[0060] Exemplarily, a gas column pressure function is determined based on the gas density function and the first wellhead pressure. The gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth. The gas column pressure function is used to determine the pressure generated by the gas column in the gas injection well at different gas-liquid interface depths.

[0061] S130. Determine the gas-liquid interface depth function in the gas injection well based on the pressure balance method, the gas column pressure function and the brine liquid column pressure.

[0062] For example, the pressure balance method is a method based on physical principles, the core idea of ​​which is that in a specific system, the pressures of different parts should be equal when in equilibrium. Since the gas column pressure and the brine liquid column pressure are equal at the gas-liquid interface, the gas-liquid interface depth function can be determined based on the pressure balance method using the gas column pressure function and the brine liquid column pressure.

[0063] S140, inputting the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure into the gas-liquid interface depth function to obtain the gas-liquid interface depth.

[0064] Exemplarily, the specific values ​​of the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure are substituted into the gas-liquid interface depth function to obtain the specific value of the gas-liquid interface depth h.

[0065] In summary, the prediction method of the gas-liquid interface depth for gas injection and brine drainage proposed in the embodiment of the present application can calculate the gas-liquid interface depth data through known parameters such as the gas density in the gas injection well, the first wellhead pressure of the gas injection well, the pressure gradient of the brine, and the second wellhead pressure of the brine drainage well. The calculation method is efficient and fast, and can achieve real-time monitoring, which greatly saves manpower and material resources.

[0066] In some examples, determining a gas column pressure function based on the gas density function and the first wellhead pressure includes:

[0067] determining an initial gas column pressure function based on the gas density function and the first wellhead pressure;

[0068] Based on the derivation algorithm, the integration algorithm and the solution algorithm, the initial air column pressure function is converted to obtain the air column pressure function.

[0069] Exemplarily, based on the gas density function and the first wellhead pressure, the initial gas column pressure function is determined, and the initial gas column pressure function is processed by sequentially applying a derivative algorithm, an integral algorithm, and a solution algorithm to ultimately obtain a more accurate and complete gas column pressure function, which can more accurately characterize the correspondence between the gas density of the gas injection well, the first wellhead pressure, and the depth of the gas-liquid interface.

[0070] In some examples, the determining of the initial gas column pressure function based on the gas density function and the first wellhead pressure is calculated by the following formula:

[0071]

[0072] Where g is the gravitational acceleration, P(0) is the first wellhead pressure of the gas injection well, h is the gas-liquid interface depth, and ρ(h) is the gas density when the gas-liquid interface depth is h.

[0073] Exemplarily, the gas column pressure at different depths is calculated by considering the gas compressibility and the formation temperature change. Based on the gas density function obtained above and the wellhead pressure of the gas injection well, the initial gas column pressure function is determined. The initial gas column pressure function is shown in formula (3).

[0074] In some examples, the initial gas column pressure function is converted based on a derivation algorithm, an integration algorithm, and a solution algorithm to obtain the gas column pressure function, including:

[0075] The initial air column pressure function is derived to obtain a first air column pressure function, where the first air column pressure function is calculated using the following formula:

[0076] P ′ (h) = ρ(h)g (4);

[0077] Where ρ(h) is the gas density when the gas-liquid interface depth is h, and g is the gravitational acceleration;

[0078] The first air column pressure function is integrated to obtain a second air column pressure function, where the second air column pressure function is calculated using the following formula:

[0079]

[0080] Among them, T w is the wellhead temperature, K is a constant, and h is the depth of the gas-liquid interface;

[0081] The second air column pressure function is solved and calculated to obtain a third air column pressure function, and the third air column pressure function is calculated by the following formula:

[0082]

[0083] Where C is the integration constant, T w is the wellhead temperature, K is a constant;

[0084] An air column pressure function is determined based on the third air column pressure function.

[0085] For example, by taking the derivative of both sides of equation (3) to obtain equation (4), substituting equation (1) into equation (4) we obtain:

[0086]

[0087] Wherein, ρ0 is the gas density under standard conditions, in m, P0 is 101325 Pa (i.e. 1 atm), T0 is 273.15 K (i.e. 0°C), g is the acceleration of gravity, P(h) is the gas column pressure at a depth of h, in Pa; T(h) is the formation temperature at a depth of h, in K.

[0088] make (K is a constant), and substitute equation (2) into equation (7) to obtain:

[0089]

[0090] Where K is a constant, P(h) is the air column pressure at depth h, in Pa, T w is the wellhead temperature, and h is the depth of the gas-liquid interface.

[0091] After transforming formula (8), we can get:

[0092]

[0093] Where K is a constant, P(h) is the air column pressure at depth h, in Pa, T w is the wellhead temperature, and h is the depth of the gas-liquid interface.

[0094] Integrating equation (9) yields equation (5), and solving equation (5) yields equation (6). Logarithmically exponentially transforming equation (6) yields:

[0095]

[0096] Where C1 = e C is an arbitrary constant, T w is the wellhead temperature, K is a constant, and h is the depth of the gas-liquid interface.

[0097] Substituting the boundary condition h = 0, P(h) = P(0) yields:

[0098]

[0099] Where C1 = e C is an arbitrary constant, T w is the wellhead temperature and K is a constant.

[0100] Comparing formula (10) with formula (11), we get:

[0101]

[0102] Where C1 = e C is an arbitrary constant, T w is the wellhead temperature and K is a constant.

[0103] In some examples, the determining of the gas column pressure function based on the gas density function and the first wellhead pressure is calculated by the following formula:

[0104]

[0105] Where P(0) is the first wellhead pressure of the gas injection well, T w is the wellhead temperature and K is a constant.

[0106] For example, equation (13) is obtained by transforming equation (12), thereby theoretically proving that the air column pressure presents a power function with depth.

[0107] In some examples, the brine liquid column pressure is obtained by:

[0108] Obtaining the brine pressure gradient and the second wellhead pressure of the brine drainage well;

[0109] Multiplying the brine pressure gradient by the gas-liquid interface depth to obtain a second parameter;

[0110] The second parameter and the second wellhead pressure are summed to obtain the brine liquid column pressure.

[0111] Exemplarily, the brine pressure gradient and the second wellhead pressure of the brine drainage well are obtained, and the brine pressure gradient represents the rate of change of the brine pressure as the depth of the brine drainage well increases. For example, if the brine pressure gradient is a certain number of Pascals per meter, it means that for every additional meter of depth, the brine pressure will increase by this gradient value accordingly. The second wellhead pressure of the brine drainage well is the pressure value at the wellhead of the brine drainage well.

[0112] The second parameter is obtained by multiplying the brine pressure gradient by the gas-liquid interface depth, which is an intermediate value calculated by using the brine pressure gradient and the gas-liquid interface depth. Because the brine pressure gradient reflects the pressure change per unit depth, and the gas-liquid interface depth represents a specific depth position, the multiplication of the two can obtain a relative change in brine pressure within the depth range from the wellhead to the gas-liquid interface, which is the second parameter.

[0113] The second parameter and the second wellhead pressure are summed to obtain the brine column pressure, which means that the brine pressure at any depth in the brine drainage well is equal to the wellhead pressure plus the pressure change from the wellhead to that depth. In this scenario, the wellhead pressure of the brine drainage well is the second wellhead pressure, and the pressure change from the wellhead of the brine drainage well to the gas-liquid interface is the second parameter calculated above. By summing the calculations, the brine column pressure at the gas-liquid interface can be obtained, which reflects the pressure generated by the brine at the gas-liquid interface in the brine drainage well.

[0114] From the pressure balance of the gas column pressure and the brine liquid column pressure at the gas-liquid interface, we can get:

[0115] P(h)=γ b h+P w ′ w (14);

[0116] Among them, γ b is the pressure gradient of brine, P w ′ w is the wellhead pressure of the brine drainage well, in Pa, and h is the depth of the gas-liquid interface.

[0117] In some examples, the gas-liquid interface depth function in the gas injection well is determined based on the pressure balance method, the gas column pressure function and the brine liquid column pressure, and is calculated by the following formula:

[0118]

[0119] Among them, T w is the wellhead temperature, K is a constant, γ b is the pressure gradient of brine, P w ′ w is the second wellhead pressure of the brine drainage well, and h is the depth of the gas-liquid interface.

[0120] Exemplarily, the combination of equations (13) and (14) yields equation (15), and the specific values ​​of the corresponding parameters such as the first wellhead pressure, wellhead temperature, brine pressure gradient, and second wellhead pressure are substituted into equation (15) to obtain the specific value of the gas-liquid interface depth h. Compared with using professional instruments to measure the position of the gas-liquid interface on-site, the present application uses known physical parameters (gravitational acceleration, brine pressure gradient, and gas density under standard conditions) and basic monitoring data during the gas injection and brine removal process (first wellhead pressure, second wellhead pressure, and surface temperature, etc.) to calculate the position of the gas-liquid interface. The calculation method of the present application is efficient and fast, and can achieve real-time monitoring, greatly saving manpower and material resources. Moreover, the present solution takes into account the influence of gas compressibility and formation temperature changes on the gas column pressure in the calculation of the gas column pressure (equations (3)-(13)). These factors have a significant impact on the determination of the gas-liquid interface depth during the gas injection and brine removal process.

[0121] like Figure 2 As shown, the present application proposes a prediction system for the depth of the gas-liquid interface for gas injection and brine removal, the system comprising: a data acquisition module 21, a first calculation module 22 and a second calculation module 23;

[0122] The data acquisition module 21 is configured to: acquire the gas density function in the gas injection well, the first wellhead pressure of the gas injection well, and the brine liquid column pressure, wherein the gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature, and the brine liquid column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well;

[0123] The first calculation module 22 is configured to: determine a gas column pressure function based on the gas density function and the first wellhead pressure, wherein the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth;

[0124] The second calculation module 23 is configured to: determine the gas-liquid interface depth function in the gas injection well based on the pressure balance method, the gas column pressure and the brine liquid column pressure; input the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure into the gas-liquid interface depth function to obtain gas-liquid interface depth data.

[0125] The effects of the above-mentioned system when applying the above-mentioned method can be found in the description of the above-mentioned method embodiment, which will not be repeated here.

[0126] like Figure 3 As shown, an embodiment of the present application further provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor, and when the processor 320 executes the computer program 311, the steps of any of the above-mentioned methods for predicting the depth of the gas-liquid interface for gas injection and brine removal are implemented.

[0127] Since the electronic device introduced in this embodiment is a device used to implement a prediction device for the depth of the gas-liquid interface for gas injection and brine removal in the embodiment of the present application, based on the method introduced in the embodiment of the present application, technical personnel in this field can understand the specific implementation mode of the electronic device of this embodiment and its various variations. Therefore, how the electronic device implements the method in the embodiment of the present application will not be introduced in detail here. As long as the equipment adopted by technical personnel in this field to implement the method in the embodiment of the present application is within the scope of protection of this application.

[0128] In the specific implementation process, when the computer program 311 is executed by the processor, it can achieve Figure 1 Any implementation manner in the corresponding embodiments.

[0129] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0130] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-readable program code.

[0131] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0132] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0133] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0134] An embodiment of the present application also provides a computer program product, which includes computer software instructions. When the computer software instructions are executed on a processing device, the processing device executes the process of the LDPC decoding method of the solid-state hard disk controller.

[0135] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can store or a data storage device such as a server or a data center that includes one or more available media integration. The available medium can be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive (SSD)), etc.

[0136] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0137] In the several embodiments provided in the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0138] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0139] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0140] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0141] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

[0142] Although the preferred embodiments of this specification have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this specification.

[0143] Obviously, those skilled in the art can make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if these modifications and variations of this specification fall within the scope of the claims of this specification and their equivalents, this specification is also intended to include these modifications and variations.

Claims

1. A method for predicting the depth of the gas-liquid interface during gas injection and brine removal, characterized in that: The method comprises: Obtaining a gas density function in a gas injection well, a first wellhead pressure of the gas injection well, and a brine column pressure, wherein the gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature, and the brine column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well; Based on the gas density function and the first wellhead pressure, a gas column pressure function is determined, wherein the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth; Determining a gas-liquid interface depth function in a gas injection well based on a pressure balance method, the gas column pressure function and the brine liquid column pressure; The first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure are input into the gas-liquid interface depth function to obtain the gas-liquid interface depth.

2. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 1, characterized in that: The determining of the gas column pressure function based on the gas density function and the first wellhead pressure comprises: determining an initial gas column pressure function based on the gas density function and the first wellhead pressure; Based on the derivation algorithm, the integration algorithm and the solution algorithm, the initial air column pressure function is converted to obtain the air column pressure function.

3. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 2, characterized in that: The initial gas column pressure function is determined based on the gas density function and the first wellhead pressure, and is calculated by the following formula: Where g is the gravitational acceleration, P(0) is the first wellhead pressure of the gas injection well, h is the gas-liquid interface depth, and ρ(h) is the gas density when the gas-liquid interface depth is h.

4. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 2, characterized in that: Based on the derivation algorithm, the integration algorithm and the solution algorithm, the initial gas column pressure function is converted to obtain the gas column pressure function, including: The initial air column pressure function is derived to obtain a first air column pressure function, where the first air column pressure function is calculated using the following formula: P′(h)=ρ(h)g; Where ρ(h) is the gas density when the gas-liquid interface depth is h, and g is the gravitational acceleration; The first air column pressure function is integrated to obtain a second air column pressure function, where the second air column pressure function is calculated using the following formula: Among them, T w is the wellhead temperature, K is a constant, and h is the depth of the gas-liquid interface; The second air column pressure function is solved and calculated to obtain a third air column pressure function, and the third air column pressure function is calculated by the following formula: Where C is the integration constant, T w is the wellhead temperature, K is a constant; An air column pressure function is determined based on the third air column pressure function.

5. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 1, characterized in that: The gas column pressure function is determined based on the gas density function and the first wellhead pressure, and is calculated by the following formula: Where P(0) is the first wellhead pressure of the gas injection well, T w is the wellhead temperature and K is a constant.

6. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 1, characterized in that: The brine liquid column pressure is obtained by the following method: Obtaining the brine pressure gradient and the second wellhead pressure of the brine drainage well; Multiplying the brine pressure gradient by the gas-liquid interface depth to obtain a second parameter; The second parameter and the second wellhead pressure are summed to obtain the brine liquid column pressure.

7. The method for predicting the depth of the gas-liquid interface during gas injection and brine removal according to claim 1, characterized in that: The gas-liquid interface depth function in the gas injection well is determined based on the pressure balance method, the gas column pressure function and the brine liquid column pressure, and is calculated by the following formula: Among them, T w is the wellhead temperature, K is a constant, γ b is the pressure gradient of brine, P′ w is the second wellhead pressure of the brine drainage well, and h is the depth of the gas-liquid interface.

8. A prediction system for the depth of the gas-liquid interface during gas injection and brine removal, characterized in that: The system comprises: a data acquisition module, a first calculation module and a second calculation module; The data acquisition module is configured to: acquire a gas density function in the gas injection well, a first wellhead pressure of the gas injection well, and a brine column pressure, wherein the gas density function is used to characterize the corresponding relationship between the gas column pressure of the gas injection well and the formation temperature, and the brine column pressure is used to characterize the corresponding relationship between the brine pressure gradient and the second wellhead pressure of the brine drainage well; The first calculation module is configured to: determine a gas column pressure function based on the gas density function and the first wellhead pressure, wherein the gas column pressure function is used to characterize the corresponding relationship between the gas density of the gas injection well, the first wellhead pressure and the gas-liquid interface depth; The second calculation module is configured to: determine the gas-liquid interface depth function in the gas injection well based on the pressure balance method, the gas column pressure and the brine liquid column pressure; input the first wellhead pressure, the wellhead temperature, the brine pressure gradient and the second wellhead pressure into the gas-liquid interface depth function to obtain gas-liquid interface depth data.

9. An electronic device, comprising: A memory and a processor, characterized in that the processor is used to implement the steps of a method for predicting the depth of a gas-liquid interface for gas injection and brine removal as described in any one of claims 1-7 when executing a computer program stored in the memory.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for predicting the depth of a gas-liquid interface for gas injection and brine removal as described in any one of claims 1 to 7 are implemented.

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