Method, system, equipment and medium for evaluating daily water yield of wellhead

Abstract

The invention provides a method, system, equipment and medium for evaluating the daily water yield of a wellhead, and the method comprises the following steps: obtaining the flow pressure gradient in a shaft in a well opening production state before water breakthrough of a target well, and obtaining the productivity relationship of the target well in a normal production state before water breakthrough; a plurality of flow pressures corresponding to different capacities are obtained on the basis of the capacity relation of the target well in the normal production state before water breakthrough, and the flow pressures are converted into wellhead oil pressure on the basis of the flow pressure gradient in a shaft; an apparent inflow dynamic curve is obtained based on the yield and wellhead oil pressure in the normal production state before water breakthrough of the target well; the initial wellhead oil pressure after water breakthrough and the corresponding wellhead daily gas production rate of the target well are collected, the initial wellhead oil pressure after water breakthrough and the corresponding wellhead daily gas production rate are marked in the apparent inflow dynamic curve, the theoretical oil pressure corresponding to the daily gas production rate is read, and the oil pressure offset caused by water breakthrough is obtained; and obtaining the flow pressure gradient in the shaft based on the oil pressure offset, and obtaining the daily water yield of the wellhead based on the flow pressure gradient in the shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas production, and in particular to a method, system, equipment and medium for evaluating daily water production at a wellhead. Background Art

[0002] The marginal and bottom water gas reservoirs in a certain area are widely distributed. At present, the water situation of such gas reservoirs is severe, and it is difficult to control the water after flooding. Water production has become one of the major risks affecting the long-term stable production of gas wells and the efficient development of gas fields. Accurately verifying the scale of water production in gas fields and accurately evaluating the speed of water invasion and the scale of water bodies are extremely important for formulating reasonable and feasible overall water control countermeasures.

[0003] In the existing technology, the commonly used means are to use mobile metering skids or arrange ground teams to verify the daily production: including ground separator + flow meter, the fluid flows out of the wellhead and is separated by phase through the separator, the gas phase passes through the orifice flow meter, and the liquid phase passes through the mass flow meter. The test cost is high, the cycle is long, and the operation is complicated. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method, system, equipment and medium for evaluating the daily water production at a wellhead, which can simply, quickly and accurately obtain the daily water production at the wellhead, and provide accurate basic data for water intrusion feature analysis and water intrusion law analysis.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for evaluating daily water production at a wellhead comprises the following steps:

[0007] Obtain the flow pressure gradient in the wellbore under the start-up production state before the target well breaks water, and obtain the production capacity relationship under the normal production state before the target well breaks water;

[0008] Based on the production capacity relationship of the target well under normal production conditions before water breakthrough, multiple flow pressures corresponding to different production capacities are obtained, and the multiple flow pressures are converted into wellhead oil pressures based on the flow pressure gradient in the wellbore;

[0009] Based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well, the apparent inflow dynamic curve is obtained;

[0010] Collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough;

[0011] The flow pressure gradient in the wellbore is obtained based on the oil pressure offset, and the daily water production at the wellhead is obtained based on the flow pressure gradient in the wellbore.

[0012] Furthermore, the back pressure well test and the one-point method empirical formula are used to obtain the production capacity relationship of the target well under normal production conditions before water breakthrough.

[0013] Furthermore, the process of converting multiple flow pressures into wellhead oil pressure based on the flow pressure gradient in the wellbore is: using the measured flow pressure gradient in the wellbore under the production state before water breakthrough to perform conversion.

[0014] Furthermore, the process of obtaining the apparent inflow dynamic curve based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well is as follows:

[0015] With the gas well production as the horizontal coordinate and the wellhead oil pressure as the vertical coordinate, different productions and the corresponding converted wellhead oil pressures are input into the same rectangular coordinate system to obtain the apparent inflow dynamic curve.

[0016] Furthermore, the oil pressure offset is:

[0017] ΔP=P gn -P, gn ;

[0018] Where ΔP is the oil pressure offset; P gn is the theoretical oil pressure; P, gn The actual oil pressure.

[0019] Furthermore, the flow pressure gradient in the wellbore is:

[0020] G. DS =ΔP / h×10 6 +G DS ;

[0021] In the formula, G, DS is the actual flow pressure gradient in the wellbore; ΔP is the oil pressure offset; G DS is the theoretical wellbore pressure gradient.

[0022] Furthermore, the daily water production at the wellhead is:

[0023]

[0024] In the formula, Q g :Daily gas production at wellhead, 10 4 m 3 / d;P wf : Bottom hole pressure, MPa; P g : Wellhead oil pressure, MPa; V g : Wellhead gas production volume, m 3 ; V w : produced water volume, m 3 ; B g : Formation gas volume coefficient, m 3 / m3 ρ g : relative density of produced gas fluid; ρ w : produced water fluid density, 10 3 kg / m 3 ; g: gravitational acceleration, g = 10N / kg; G DS : flow pressure gradient, Pa / m; constant ρ air:

[0025] 1.293, kg / m 3 .

[0026] A method for evaluating daily water production at a wellhead, comprising:

[0027] The acquisition module is used to obtain the flow pressure gradient in the wellbore under the well opening production state before the target well breaks water, and obtain the production capacity relationship under the normal production state before the target well breaks water;

[0028] The first processing module is used to obtain a plurality of flow pressures corresponding to different production capacities based on the production capacity relationship of the target well under normal production conditions before water breakthrough, and convert the plurality of flow pressures into wellhead oil pressures based on the flow pressure gradient in the wellbore;

[0029] Curve module, used to obtain the apparent inflow dynamic curve based on the production and wellhead oil pressure under normal production state before water breakthrough of the target well;

[0030] The second processing module is used to collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough;

[0031] The output module is used to obtain the flow pressure gradient in the wellbore based on the oil pressure offset, and to obtain the daily water production at the wellhead based on the flow pressure gradient in the wellbore.

[0032] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a method for evaluating the daily water production of a wellhead are implemented.

[0033] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for evaluating daily water production at a wellhead.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] The present invention provides a method, system, device and medium for evaluating the daily water production at a wellhead, comprising the following steps: obtaining the flow pressure gradient in the wellbore under the well opening production state before water appears in the target well, and obtaining the capacity relationship under the normal production state before water appears in the target well; obtaining a plurality of flow pressures corresponding to different capacity levels based on the capacity relationship under the normal production state before water appears in the target well, and converting the plurality of flow pressures into wellhead oil pressures based on the flow pressure gradient in the wellbore; obtaining an apparent inflow dynamic curve based on the production and wellhead oil pressure under the normal production state before water appears in the target well; collecting the initial wellhead oil pressure after water appears in the target well The initial wellhead oil pressure after water breakthrough and the corresponding daily gas production at the wellhead are marked in the apparent inflow dynamic curve, the theoretical oil pressure corresponding to the daily gas production is read, and the oil pressure offset caused by water breakthrough is obtained; the flow pressure gradient in the wellbore is obtained based on the oil pressure offset, and the daily water production at the wellhead is obtained based on the flow pressure gradient in the wellbore; the application can simply, quickly and accurately obtain the daily water production at the wellhead, improve the accurate basic data for water invasion feature analysis and water invasion law analysis, and save the cost of multiple verifications of wellhead production by mobile metering skids or professional ground metering teams. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of a method for evaluating daily water production at a wellhead in an embodiment of the present invention;

[0037] Figure 2 It is a gas well visual inflow dynamic curve diagram in an embodiment of the present invention;

[0038] Figure 3 This is a graph showing the visual inflow dynamics of the B9 well in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the initial wellhead oil pressure after water breakthrough and the corresponding wellhead daily gas production marked on the B9 well apparent inflow dynamic curve diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] The present invention provides a method for evaluating the daily water production of a wellhead, such as Figure 1 As shown, the following steps are included:

[0044] Obtain the flow pressure gradient in the wellbore under the start-up production state before the target well breaks water, and obtain the production capacity relationship under the normal production state before the target well breaks water;

[0045] Based on the production capacity relationship of the target well under normal production conditions before water breakthrough, multiple flow pressures corresponding to different production capacities are obtained, and the multiple flow pressures are converted into wellhead oil pressures based on the flow pressure gradient in the wellbore;

[0046] Based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well, the apparent inflow dynamic curve is obtained;

[0047] Collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough;

[0048] The flow pressure gradient in the wellbore is obtained based on the oil pressure offset, and the daily water production at the wellhead is obtained based on the flow pressure gradient in the wellbore.

[0049] Preferably, the production capacity relationship under normal production state before water breakthrough of the target well is obtained by back pressure well test and one-point method empirical formula; it should be noted that the back pressure well test refers to testing and recording the corresponding bottom hole flow pressure by changing the wellhead daily gas production of the test gas well under certain formation pressure conditions;

[0050] Furthermore, the one-point empirical formula generally refers to the use of multi-point capacity test data analysis results of multiple gas wells in the same block, through data regression analysis, to obtain a more reliable special one-point capacity equation and unimpeded flow calculation formula.

[0051] Gas well productivity generally refers to the gas production capacity of a gas well, which is usually measured by open flow rate.AOF As the name implies, it refers to the limit production of a gas well. It is generally defined as the bottom hole flowing pressure, which refers to the pressure at the gas production layer level when it drops to 0, or when the absolute pressure drops to atmospheric pressure (p wf =0.1MPa) of gas well production; Generally speaking, the open flow rate q AOF It is impossible to measure it directly, because the bottom hole pressure cannot be vented to atmospheric pressure. AOF It can only be calculated through formulas or graphical methods.

[0052] Productivity testing is very important for gas well testing. There are three commonly used testing methods in gas reservoirs, including back pressure testing (flow after flow), isochronal testing (isochronal) and modified isochronal testing (modifiedisochronal). These methods require the measurement of 3-4 stable production and corresponding bottom hole pressure production point data.

[0053] Preferably, the process of converting multiple flow pressures into wellhead oil pressure based on the flow pressure gradient in the wellbore is: using the measured flow pressure gradient in the wellbore under the production state before water breakthrough to perform conversion.

[0054] Preferably, the process of obtaining the apparent inflow dynamic curve based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well is:

[0055] like Figure 2 As shown in the figure, with the gas well production as the horizontal coordinate and the wellhead oil pressure as the vertical coordinate, different productions and the corresponding converted wellhead oil pressures are input into the same rectangular coordinate system to obtain the apparent inflow dynamic curve.

[0056] Preferably, the oil pressure offset is:

[0057] ΔP=P gn -P, gn ;

[0058] Where ΔP is the oil pressure offset; P gn is the theoretical oil pressure; P, gn The actual oil pressure.

[0059] Preferably, the flow pressure gradient in the wellbore is:

[0060] G. DS =ΔP / h×10 6 +G DS ;

[0061] In the formula, G, DS is the actual flow pressure gradient in the wellbore; ΔP is the oil pressure offset; G DS is the theoretical wellbore pressure gradient.

[0062] Preferably, the daily water production at the wellhead is:

[0063]

[0064] In the formula, Q g :Daily gas production at wellhead, 10 4 m 3 / d;P wf : Bottom hole pressure, MPa; P g : Wellhead oil pressure, MPa; V g : Wellhead gas production volume, m 3 ; V w : produced water volume, m 3 ; B g : Formation gas volume coefficient, m 3 / m 3 ρ g : relative density of produced gas fluid; ρ w : produced water fluid density, 10 3 kg / m 3 ; g: gravitational acceleration, g = 10N / kg; G DS : flow pressure gradient, Pa / m; constant ρ air: 1.293, kg / m 3 .

[0065] Example:

[0066] The gas production well B9 was put into production at the section 4802-4900m. A pressure recovery test was carried out in May 2021. During the test, flow pressure and temperature gradient tests (Table 1), static pressure and temperature gradient tests (Table 2) and shut-in pressure recovery tests were carried out. The present invention was used to draw the gas well apparent inflow dynamic curve diagram of this well, and the corresponding wellhead daily gas production under different oil pressure regimes was obtained.

[0067] The formation gas volume coefficient of this well (m 3 / m 3 ): 0.00266 (can be obtained through PVT analysis report and software calculation); natural gas relative density: 0.5731 (can be obtained through natural gas analysis report); formation water density: 1.14g / cm 3 (can be obtained through the produced water analysis report); constant ρ air: 1.293kg / m 3 .

[0068] Table 1 B9 well flow pressure and temperature gradient monitoring results

[0069]

[0070]

[0071] Table 2B9 Well Static Pressure and Temperature Gradient Monitoring Results

[0072]

[0073] Method flow:

[0074] S1: Based on the measured bottom hole pressure and production data of B9 well, the open flow rate QAOF of B9 well is estimated to be 116×10 4 m 3 / d.

[0075] The Great North Point Method empirical formula is:

[0076]

[0077] The one-point empirical production capacity equation of the B9 well is:

[0078]

[0079] Among them, q AOF : Unimpeded flow, 10 4 m 3 / d;q g :Daily gas production at wellhead, 10 4 m 3 / d;P wf : Bottom hole pressure, MPa; P R : Formation pressure, MPa.

[0080] S2: The measured data converts the formation pressure of the gas well production layer in the middle depth (4851m) to 76.70MPa. Based on the production capacity equation (1), Q1, Q2, Q3, Q4, Q5, ... Q n Output (n≤Q AOF ) corresponds to the flow pressure P wf According to the measured flow temperature and pressure gradient data in Table 1, the flow pressure P wf Converted to wellhead oil pressure P gn , see Table 3 for details.

[0081] Table 3 The relationship between the production of B9 well and the bottom hole flow pressure and wellhead oil pressure

[0082] Serial number <![CDATA[Daily gas production (10 4 m 3 / d)]]> Formation pressure (MPa) Bottom hole pressure (MPa) Wellhead oil pressure (MPa) <![CDATA[Q1]]> 5 76.70 76.49 61.94 <![CDATA[Q2]]> 10 76.70 76.03 61.47 <![CDATA[Q3]]> 15 76.70 75.35 60.80 <![CDATA[Q4]]> 20 76.70 74.49 59.94 <![CDATA[Q5]]> 25 76.70 73.45 58.90 <![CDATA[Q6]]> 30 76.70 72.24 57.68 <![CDATA[Q7]]> 35 76.70 70.85 56.30 <![CDATA[Q8]]> 40 76.70 69.28 54.73 <![CDATA[Q9]]> 45 76.70 67.53 52.98 <![CDATA[Q 10 ]]> 50 76.70 65.58 51.03 <![CDATA[Q 11 ]]> 55 76.70 63.43 48.88 <![CDATA[Q 12 ]]> 60 76.70 61.05 46.50 <![CDATA[Q 13 ]]> 65 76.70 58.43 43.87 <![CDATA[Q 14 ]]> 70 76.70 55.52 40.97 <![CDATA[Q 15 ]]> 75 76.70 52.30 37.74 <![CDATA[Q 16 ]]> 80 76.70 48.69 34.13 <![CDATA[Q 17 ]]> 85 76.70 44.61 30.05 <![CDATA[Q 18 ]]> 90 76.70 39.91 25.36 <![CDATA[Q 19 ]]> 95 76.70 34.36 19.81 <![CDATA[Q 20 ]]> 100 76.70 27.44 12.89 <![CDATA[Q 21 ]]> 105 76.70 17.61 3.06

[0083] S3: With the gas well production as the horizontal axis and the wellhead oil pressure as the vertical axis, draw the apparent inflow dynamic curve of the B9 well, such as Figure 3 shown.

[0084] S4: The oil pressure of Well B9 dropped rapidly on September 14, 2021. The analysis of liquid samples taken from the wellhead showed that the chloride ion content was as high as 12.75×10 4mg / L, confirming that the well has seen water. On September 26, 2021, ground measurement work was carried out to verify that the wellhead oil pressure was 52.84 MPa and the daily gas production was 35.36×10 4 m 3 / d, with a daily water output of 120.5t.

[0085] Q after seeing water g =35.36×10 4 m 3 / d,P, g =52.84MPa. g =35.36×10 4 m 3 / dThe wellhead daily gas production data is marked on the B9 well visual inflow dynamic curve to obtain the corresponding wellhead oil pressure P g =56.19MPa, such as Figure 4 shown.

[0086] S5: Daily gas production is Q g =35.36×10 4 m 3 / d Oil pressure deviation due to water:

[0087] ΔP=P g -P, g =56.19-52.84=3.35MPa;

[0088] Then the flow pressure gradient in the wellbore can be obtained as:

[0089] G. DS =ΔP / h×10 6 +G DS =3.35 / 4851×106+3000=3690Pa / 100m

[0090] S6: Calculate the daily water production at the wellhead:

[0091]

[0092] M W =V W ×ρ W =110.31*1.14=125.75t.

[0093] The present invention provides a method for evaluating daily water production at a wellhead, comprising:

[0094] The acquisition module is used to obtain the flow pressure gradient in the wellbore under the well opening production state before the target well breaks water, and obtain the production capacity relationship under the normal production state before the target well breaks water;

[0095] The first processing module is used to obtain a plurality of flow pressures corresponding to different production capacities based on the production capacity relationship of the target well under normal production conditions before water breakthrough, and convert the plurality of flow pressures into wellhead oil pressures based on the flow pressure gradient in the wellbore;

[0096] Curve module, used to obtain the apparent inflow dynamic curve based on the production and wellhead oil pressure under normal production state before water breakthrough of the target well;

[0097] The second processing module is used to collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough;

[0098] The output module is used to obtain the flow pressure gradient in the wellbore based on the oil pressure offset, and to obtain the daily water production at the wellhead based on the flow pressure gradient in the wellbore.

[0099] In another embodiment of the present invention, a computer device is provided, the computer device comprising a processor and a memory, the memory being used to store a computer program, the computer program comprising program instructions, and the processor being used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions in a computer storage medium to implement a corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a method for evaluating the daily water production of a wellhead.

[0100] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of a method for evaluating the daily water production of a wellhead in the above embodiment.

[0101] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 processor, or other programmable data processing device to produce 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.

[0103] 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 including 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.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating daily water production at a wellhead, characterized in that: The following steps are involved: Obtain the flow pressure gradient in the wellbore under the start-up production state before the target well sees water, and obtain the production capacity relationship under the normal production state before the target well sees water; Based on the production capacity relationship of the target well under normal production conditions before water breakthrough, multiple flow pressures corresponding to different production capacities are obtained, and the multiple flow pressures are converted into wellhead oil pressures based on the flow pressure gradient in the wellbore; Based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well, the apparent inflow dynamic curve is obtained; Collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough; The flow pressure gradient in the wellbore is obtained based on the oil pressure offset, and the daily water production at the wellhead is obtained based on the flow pressure gradient in the wellbore.

2. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The production capacity relationship of the target well under normal production conditions before water breakthrough is obtained by using back pressure well test and one-point method empirical formula.

3. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The process of converting multiple flow pressures into wellhead oil pressure based on the flow pressure gradient in the wellbore is: using the measured flow pressure gradient in the wellbore under the production state before water breakthrough to perform conversion.

4. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The process of obtaining the apparent inflow dynamic curve based on the production and wellhead oil pressure in the normal production state before water breakthrough of the target well is as follows: With the gas well production as the horizontal coordinate and the wellhead oil pressure as the vertical coordinate, different productions and the corresponding converted wellhead oil pressures are input into the same rectangular coordinate system to obtain the apparent inflow dynamic curve.

5. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The oil pressure offset is: ΔP=P gn -P、 gn ; Where ΔP is the oil pressure offset; P gn is the theoretical oil pressure; P` gn The actual oil pressure.

6. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The flow pressure gradient in the wellbore is: G` DS =ΔP / h×10 6 +G DS ; In the formula, G` DS is the actual flow pressure gradient in the wellbore; ΔP is the oil pressure offset; G DS is the theoretical wellbore pressure gradient.

7. A method for evaluating daily water production at a wellhead according to claim 1, characterized in that: The daily water production at the wellhead is: In the formula, Q g :Daily gas production at wellhead, 10 4 m 3 / d;P wf : Bottom hole pressure, MPa; P g : Wellhead oil pressure, MPa; V g : Wellhead gas production volume, m 3 ; V w : produced water volume, m 3 ; B g : Formation gas volume coefficient, m 3 / m 3 ρ g : Relative density of produced gas fluid; ρ w : produced water fluid density, 10 3 kg / m 3 ; g: acceleration due to gravity, g = 10N / kg; G DS : flow pressure gradient, Pa / m; constant ρ air: 1.293, kg / m 3 .

8. A method for evaluating daily water production at a wellhead, characterized in that: A method for evaluating daily water production at a wellhead according to any one of claims 1 to 7, comprising: The acquisition module is used to obtain the flow pressure gradient in the wellbore under the well opening production state before the target well breaks water, and obtain the production capacity relationship under the normal production state before the target well breaks water; The first processing module is used to obtain a plurality of flow pressures corresponding to different production capacities based on the production capacity relationship of the target well under normal production conditions before water breakthrough, and convert the plurality of flow pressures into wellhead oil pressures based on the flow pressure gradient in the wellbore; Curve module, used to obtain the apparent inflow dynamic curve based on the production and wellhead oil pressure under normal production state before water breakthrough of the target well; The second processing module is used to collect the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the target well, and mark the initial wellhead oil pressure and the corresponding daily gas production at the wellhead after water breakthrough in the apparent inflow dynamic curve, read the theoretical oil pressure corresponding to the daily gas production, and obtain the oil pressure deviation caused by water breakthrough; The output module is used to obtain the flow pressure gradient in the wellbore based on the oil pressure offset, and to obtain the daily water production at the wellhead based on the flow pressure gradient in the wellbore.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of a method for evaluating daily water production at a wellhead as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a method for evaluating daily water production at a wellhead as described in any one of claims 1 to 7 are implemented.

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