Method, system and equipment for evaluating installation depth of multi-stage throttle valve and medium

Abstract

The invention discloses a method, a system and equipment for evaluating the installation depth of a multi-stage throttle valve and a medium, relates to evaluation of the installation depth of a throttle valve in oil and gas exploitation, and aims to solve the technical problem that the installation depth of the multi-stage throttle valve cannot be evaluated in the process of installing the throttle valve. Comprising the following steps: acquiring initial data of an oil well, constructing a shaft infinitesimal section, setting a ground temperature gradient, setting pressure change, calculating outlet pressure, calculating pressure deviation, judging that a wellhead is reached, comparing errors, updating the pressure change, updating pressure before throttling, calculating outlet temperature, adjusting mounting parameters of a throttling valve, calculating data after throttling, and replacing the pressure and the temperature. Judging other throttle valves, and outputting results and corresponding logics and algorithms. According to the depth of the shaft and the corresponding pressure and temperature, the temperature and pressure change conditions of the whole well section can be obtained, and the downstream cooling effect of each stage of throttling valve under the corresponding depth can be evaluated by setting the nozzle diameter and the installation depth for each stage of the multi-stage throttling valve.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas extraction technology, and relates to the assessment of the installation depth of throttle valves during offshore oil and gas extraction, and particularly to a method, system, equipment and medium for assessing the installation depth of multi-stage throttle valves. Background Technology

[0002] With the increasing depth of offshore oil and gas extraction in recent years, the pressure and temperature during oil and gas production have also increased. Traditional wellhead throttling methods are prone to producing hydrates due to sudden changes in temperature and pressure, causing blockage of gas production pipelines and damage to surface equipment. Furthermore, surface throttling is prone to leakage of high-temperature and high-pressure oil and gas, which affects production and threatens the safety of surface workers, posing significant safety hazards.

[0003] Downhole choke valves enable throttling, pressure reduction, and cooling processes to occur within the well, minimizing wellhead blockage and oil / gas leakage. However, due to current offshore downhole oil and gas extraction depths exceeding several thousand meters, designers and operators find it difficult to rely on experience to place choke valves of appropriate nozzle diameters at suitable locations in deep wells. Improper selection of choke valve installation depth and nozzle diameter can easily lead to hydrate blockage of the choke valve, resulting in valve damage and production shutdown. When a single-stage choke valve is insufficient to meet throttling and pressure reduction requirements, the combined use of multiple choke valves further complicates selection and layout. Therefore, there is an urgent need for a tool that can guide the selection of choke valve nozzle diameters and depth layout under specific operating conditions, assisting designers and operators in selecting and installing choke valves, improving work efficiency, and ensuring safety.

[0004] The installation depth of a downhole throttle valve determines the environmental pressure and temperature it will face during operation. Inappropriate installation depth and throttle nozzle selection will affect the valve's service life, impacting oil and gas production and potentially causing safety accidents. Therefore, it is necessary to provide a method for evaluating the installation depth of multi-stage throttle valves during the installation process. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that the installation depth of multi-stage throttle valves cannot be evaluated during the installation process of existing technologies, and to provide a method, system, device and medium for evaluating the installation depth of multi-stage throttle valves.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution: A method for evaluating the installation depth of a multi-stage throttle valve includes the following steps: Step 1: Obtain initial data for the oil well; Obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature ; Step 2, construct wellbore micro-segments; Construct wellbore micro-segments based on the initial section of the wellbore of the oil well to be evaluated; Step 3, set the geothermal gradient; Geothermal gradients are set based on the geological parameters of the location of the oil well to be evaluated. ; Step 4, set the pressure variation; Based on the geological parameters of the well location to be evaluated, the pressure changes in the pre-set wellbore micro-segments are calculated. ; Step 5: Calculate the outlet pressure; Calculate the outlet pressure of the corresponding wellbore micro-element using formula (1). The specific calculation formula is as follows: (1) in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; Step 6: Calculate the pressure deviation; Calculate the pressure deviation using formula (2) The specific calculation formula is as follows: (2) Step 7: Determine if the wellhead has been reached; Determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has, proceed to step 16; if it has not, proceed to step 8. Step 8, Error Comparison; Determine pressure deviation With pressure changes If the error is less than the preset expected error, proceed to step 10 to reduce pressure; if it is not less, proceed to step 9 to update the pressure and continue iterating. Step 9, update pressure changes; Using the pressure deviation obtained in step 6 Replace and update the pressure change in step 4 with the value. Then proceed to step 4; Step 10, Update the pressure before throttling. The outlet pressure in step 5 Update to pre-throttling pressure, which is used to calculate post-throttling data; Step 11, calculate the outlet temperature; The outlet temperature of the corresponding wellbore micro-element segment is calculated using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: (3); (4); in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure. Step 12: Adjust the throttle valve installation parameters; Adjust the throttling valve installation parameters according to the pre-throttling pressure in step 10 and the pre-throttling temperature in step 11. The installation parameters include the installation depth, the throttling nozzle diameter of the throttling valve, whether multi-stage throttling is used, and the number of throttling stages. Step 13, calculate the data after throttling; Calculate the post-throttling pressure using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: (5); (6) in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; Indicates the diameter of the throttle nozzle, in meters (m). Step 14, replace pressure and temperature; The pressure after throttling calculated in step 13 Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature ; Step 15, determine other throttle valves; Determine if there are other throttle valves; if so, proceed to step 12; if not, proceed to step 5. Step 16, output the result; The evaluation is completed, and the results are output, including the pressure distribution curve of the entire wellbore, the temperature distribution curve of the entire wellbore, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

[0007] Furthermore, in step 5, the pressure value Pressure value Pressure value The calculation formulas are as follows: ; ; ; in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. Indicates the density of oil and gas. Represents gravitational acceleration. Indicates the angle between the pipe and the horizontal line. Indicates the coefficient of friction. Indicates the dynamic viscosity of oil and gas. This indicates the diameter of the oil pipe.

[0008] Furthermore, oil and gas density The calculation formula is: ; in, Indicates the relative density of oil and gas; This represents the average pressure of oil and gas in the selected tubing unit, in MPa; This represents the gas compressibility coefficient corresponding to the average pressure; it is dimensionless. This represents the average temperature of the selected micro-element segment.

[0009] Furthermore, in step 7, the criterion for determining whether the end of the current wellbore micro-segment has reached the wellhead is as follows: Determine whether the endpoint depth of the current micro-segment is equal to or exceeds the total wellbore depth; if If the wellhead is reached, it is determined that the wellhead has been reached; otherwise, it is determined that the wellhead has not been reached. in, This indicates the calculation segment length of the current infinitesimal segment. Indicates the total well depth.

[0010] A system for evaluating the installation depth of a multi-stage throttle valve, comprising: The oil well initial data acquisition module is used to obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature ; The wellbore micro-segment construction module is used to construct wellbore micro-segments based on the initial segment of the wellbore of the oil well to be evaluated. The geothermal gradient setting module is used to set the geothermal gradient based on the geological parameters of the location of the oil well to be evaluated. ; The pressure variation setting module is used to preset the pressure variation of a micro-section of the wellbore based on the geological parameters of the location of the well to be evaluated. ; The outlet pressure calculation module is used to calculate the outlet pressure of the corresponding wellbore micro-element section using formula (1). The specific calculation formula is as follows: (1) in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; The pressure deviation calculation module is used to calculate the pressure deviation using formula (2). The specific calculation formula is as follows: (2) The wellhead reach determination module is used to determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has reached the wellhead, it proceeds to the output result module; if it has not reached the wellhead, it proceeds to the error comparison module. The error comparison module is used to determine the pressure deviation. With pressure changes If the error between the two is less than the preset expected error, then proceed to the pre-throttling pressure update module and proceed to the next micro-segment; if it is not less than the expected error, then proceed to the pressure change update module to update the pressure and continue iterating. The pressure change update module is used to calculate the pressure deviation obtained from the pressure deviation calculation module. Replace and update the pressure change setting module's value for the pressure change. Then, it enters the pressure change setting module; The pre-throttling pressure update module is used to update the outlet pressure of the outlet pressure calculation module. Update to pre-throttling pressure, which is used to calculate post-throttling data; The outlet temperature calculation module is used to calculate the outlet temperature of the corresponding wellbore micro-element segment using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: (3); (4); in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure. The throttle valve installation parameter adjustment module is used to adjust the throttle valve installation parameters based on the throttle pressure update module and the outlet temperature calculation module. The installation parameters include the installation depth, the throttle nozzle diameter, whether multi-stage throttling is used, and the number of throttling stages. The post-throttling data calculation module is used to calculate the post-throttling pressure using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: (5); (6) in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; Indicates the diameter of the throttle nozzle, in meters (m). The pressure and temperature replacement module is used to replace the pressure calculated by the post-throttling data calculation module. Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature ; The other throttle valve judgment module is used to determine whether other throttle valves exist; if they exist, the module proceeds to the throttle valve installation parameter adjustment module; if they do not exist, the module proceeds to the outlet pressure calculation module. The output results module is used to evaluate the completion and output the results, including the whole wellbore pressure distribution curve, the whole wellbore temperature distribution curve, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

[0011] A computer device includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method described above.

[0012] A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the above-described method.

[0013] The beneficial effects of this invention are as follows: 1. In this invention, by analyzing fluid heat transfer and geothermal changes, a model of oil and gas temperature changes within the wellbore and the cooling effect of the throttle valve can be constructed. This allows for the evaluation of the throttle valve's cooling performance, improving work efficiency and ensuring safety. Specifically, this solution can obtain the temperature and pressure changes throughout the wellbore based on the wellbore depth and its corresponding pressure and temperature data. By simply setting the nozzle diameter and installation depth for each stage of the multi-stage throttle valve, the downstream cooling effect of each stage at the corresponding depth can be evaluated. This facilitates the rapid assessment of the feasibility of the installation depth when multiple throttle valves are used together. This solution can construct a model of oil and gas temperature changes within the wellbore and the cooling effect of the throttle valve based on the analysis of fluid heat transfer and geothermal changes, thereby evaluating the throttle valve's cooling performance, improving work efficiency, and ensuring safety.

[0014] 2. In this invention, the multi-stage choke control system completes the choke pressure drop by decomposing it into two or three stages. The fluid first passes through a fixed choke valve to bear the pressure drop in the high-pressure stage, and then flows through an adjustable choke valve. The adjustable choke valve regulates and controls the back pressure, making the operation very convenient. It can solve problems such as blockage, puncture, and breakage of the choke valve under high pressure drop. In addition, the system is equipped with multi-stage pressure sensors, which can reflect the upstream and downstream pressure values ​​of any stage of the choke valve. This not only provides convenience for well control operators to carry out precise well control, but also allows the failure status of the choke valve to be judged based on the pressure difference between the upstream and downstream of the choke valve. 3. In this invention, the temperature and pressure changes of the entire well section can be obtained based on the wellbore depth and its corresponding pressure and temperature. Only the nozzle diameter and installation depth of each stage of the multi-stage throttle valve need to be set, and the downstream cooling at the corresponding depth of each stage of the throttle valve can be evaluated. This is beneficial for quickly evaluating the feasibility of the installation depth when multiple throttle valves are used together.

[0015] 4. In the analysis of wellbore temperature and pressure distribution, the temperature and pressure changes within the wellbore exhibit a clear regularity with depth. During deep-water drilling, as the seawater depth increases, the wellbore temperature gradually increases in the upper part and gradually decreases in the lower part. This indicates that the geothermal gradient has a significant impact on the wellbore temperature distribution. At the same time, the pressure and temperature changes within the wellbore are also affected by various factors such as fluid flow, frictional heat generation, and heat transfer coefficient. By establishing a coupled analysis model of wellbore pressure and temperature, these factors can be comprehensively considered, improving calculation accuracy and engineering applicability. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the present invention; Figure 2 This is a schematic diagram of a single wellbore micro-segment in this invention; Figure 3 This is a schematic diagram of the throttling from one wellbore micro-segment to the next in this invention; Figure 4 This is a partial screenshot of the software program code corresponding to this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0018] Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1 This embodiment provides a method for evaluating the installation depth of a multi-stage throttle valve, used to assess the installation depth of throttle valves, especially multi-stage throttle valves. Each step in this evaluation method is implemented using computer software and program code, conforming to the technical solutions stipulated by patent law. Furthermore, the relevant inventors are currently registering the software and program implementing this evaluation method for software copyright (titled: Downhole Throttling Analysis Software under Multiple Operating Conditions). Figure 4 This is a screenshot of part of the code of the software program corresponding to this method.

[0020] like Figure 1 As shown, it includes the following steps: Step 1: Obtain initial data for the oil well; Obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature .

[0021] The aforementioned initial pressure Well depth H and initial temperature All of these can be directly obtained from the system at the original well to be evaluated. In subsequent iterations and throttling calculations, the initial pressure will be... ,temperature The pressure and temperature at the bottom of the first micro-segment of the wellbore.

[0022] Step 2, construct wellbore micro-segments; Construct wellbore micro-segments based on the initial section of the wellbore of the oil well to be evaluated.

[0023] When constructing wellbore micro-segments, the length of each micro-segment must be set. That is, based on the starting segment of the wellbore, the length of the well section to be constructed for each micro-segment is set.

[0024] Step 3, set the geothermal gradient; Geothermal gradients are set based on the geological parameters of the location of the oil well to be evaluated. .

[0025] The geological parameters here can be derived from geological exploration or measurement results.

[0026] Step 4, set the pressure variation; Based on the geological parameters of the well location to be evaluated, the pressure changes in the pre-set wellbore micro-segments are calculated. .

[0027] Pressure change in this micro-element segment The value can be set according to the length of the micro-segment. For example, if the length of the micro-segment is 1m, the pressure change of the micro-segment can be set to 0.01MPa. This value is only used for estimation and subsequent calculations and will be corrected during the calculation process. Therefore, it can be determined by those skilled in the art based on the actual situation.

[0028] Step 5: Calculate the outlet pressure; The outlet pressure of the corresponding micro-segment of the wellbore The calculation formula is: (1) Among them, pressure value Pressure value Pressure value Oil and gas density The calculation formulas are as follows: ; ; ; ; in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; Indicates the density of oil and gas. Represents gravitational acceleration. Indicates the angle between the pipe and the horizontal line. This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. Indicates the coefficient of friction. Indicates the dynamic viscosity of oil and gas. Indicates the diameter of the oil pipe; Indicates the relative density of oil and gas; This represents the average pressure of oil and gas in the selected tubing unit, in MPa; This represents the gas compressibility coefficient corresponding to the average pressure; it is dimensionless. This represents the average temperature of the selected micro-element segment.

[0029] pressure value , , All three pressure loss values ​​are related to the downhole depth z. In the calculation, the pressure change value in each micro-element is obtained by performing integration or difference processing within different depth intervals (z0-z1, z1-z2, ...) within the micro-element.

[0030] like Figure 2 , Figure 3 As shown, this outlet pressure This refers to the pressure value before throttling and pressure reduction, which is only related to depth changes. During subsequent throttling, the outlet pressure of the micro-element will be... As the pressure before throttling, it is used in subsequent calculations of pre- and post-throttling data.

[0031] Step 6: Calculate the pressure deviation; Calculate the pressure deviation using formula (2) The specific calculation formula is as follows: (2).

[0032] Calculate and determine the pressure deviation At that time, it is when the total pressure is satisfied ( , , (Three pressure values) and pressure changes When the error is less than or equal to the expected error, , , The sum of the three pressure values ​​is the pressure deviation. .

[0033] Step 7: Determine if the wellhead has been reached; Determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has, proceed to step 16; if it has not, proceed to step 8.

[0034] When determining whether the end of the current wellbore micro-segment has reached the wellhead, the criterion is as follows: Determine whether the endpoint depth of the current micro-segment is equal to or exceeds the total wellbore depth; if If the wellhead is reached, it is determined that the wellhead has been reached; otherwise, it is determined that the wellhead has not been reached. in, This indicates the calculation segment length of the current infinitesimal segment. Indicates the total well depth.

[0035] Step 8, Error Comparison; Determine pressure deviation With pressure changes If the error is less than the preset expected error, proceed to step 10 to reduce pressure; if it is not less, proceed to step 9 to update the pressure and continue iterating.

[0036] The expected error is a pre-set threshold, which can be determined by those skilled in the art based on the actual conditions of the oil well.

[0037] When the error is greater than or equal to the preset expected error, and the iterative calculation is repeated in steps 9 and 4-8, the pressure deviation is first calculated as described in step 9. Replace the current pressure change Then proceed to steps 4-8 to calculate the new pressure value. , , and pressure deviation It then determines whether the wellhead has been reached, and repeats this process iteratively until the adjustment (i.e., pressure deviation) is satisfied. With pressure changes The difference is less than the expected error, and then the depth value of the endpoint of the micro-element segment is changed. Then, perform pressure calculations for the next infinitesimal segment.

[0038] Step 9, update pressure changes; Using the pressure deviation obtained in step 6 Replace and update the pressure change in step 4 with the value. Then proceed to step 4.

[0039] Step 10, Update the pressure before throttling. The outlet pressure in step 5 Update to pre-throttling pressure, which is used to calculate post-throttling data.

[0040] Step 11, calculate the outlet temperature; The outlet temperature of the corresponding wellbore micro-element segment is calculated using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: (3); (4); in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure.

[0041] geothermal gradient It expresses the difference in wellbore temperature with depth, and is used to obtain the average temperature of a micro-element segment of the wellbore in order to solve for density. Then, the outlet pressure of the infinitesimal element segment can be solved. When export pressure is received Then, the pressure deviation coefficient Z under that pressure can be obtained, and the outlet temperature can be calculated using the above formula. .

[0042] Step 12: Adjust the throttle valve installation parameters; Adjust the throttling valve installation parameters according to the pre-throttling pressure in step 10 and the pre-throttling temperature in step 11. The installation parameters include the installation depth, the diameter of the throttling valve nozzle, whether multi-stage throttling is used, and the number of throttling stages.

[0043] When adjusting the installation parameters, if the temperature drop is too large, it can be satisfied by increasing the diameter of the throttle valve or making the installation depth shallower, based on the input parameters.

[0044] Step 13, calculate the data after throttling; like Figure 3 As shown, the pressure after throttling is calculated using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: (5); (6) in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; This indicates the diameter of the throttle nozzle, in meters (m).

[0045] Step 14, replace pressure and temperature; The pressure after throttling calculated in step 13 Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature It is used for iterative calculation of the next wellbore micro-segment.

[0046] Step 15, determine other throttle valves; Determine if there are other throttle valves; if so, proceed to step 12; if not, proceed to step 5 to calculate the temperature and pressure of the next wellbore micro-segment and adjust the throttle valve installation parameters.

[0047] Step 16, output the result; The evaluation is completed, and the results are output, including the pressure distribution curve of the entire wellbore, the temperature distribution curve of the entire wellbore, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

[0048] This embodiment is based on the constructed wellbore depressurization model, which is specifically as follows: The wellbore pressure reduction model depicts the variation of oil and gas pressure within the wellbore with well depth. In the design of the choke valve installation depth, the downhole pressure at the current choke valve installation depth is given by the wellbore pressure reduction model; therefore, the wellbore pressure reduction model is the foundation for choke valve pressure reduction analysis.

[0049] To ensure the accuracy of the throttling pressure reduction of the downhole throttling valve under different installation depths and selection conditions, the wellbore pressure reduction model should be able to depict the pressure distribution of the entire wellbore section at a specified depth, and simultaneously depict the pressure distribution from the bottom of the well to the throttling nozzle and from the throttling point to the surface.

[0050] Due to the complex downhole environment of oil and gas wells, it is difficult to directly obtain the pressure distribution of the entire well section. Therefore, the pressure model will be built in a segmented manner, such as... Figure 2 As shown.

[0051] Figure 2 In the diagram, z represents the downhole depth at the bottom of the micro-element, dz represents the length of the micro-element, p1 and T1 represent the gas pressure and temperature before flowing into the micro-element, p2 and T2 represent the gas pressure and temperature after flowing out of the micro-element, and p and T represent the average pressure and temperature of the gas in the micro-element.

[0052] The gas pressure change in the infinitesimal segment can be expressed as: ; in, This represents the unit change in oil and gas pressure, expressed in MPa. Indicates the length of the selected unit tubing, in meters; This indicates the density of oil and gas, in kg / m³. 3 g represents gravitational acceleration, m / s² 2 ; Indicates the angle between the pipe and the horizontal line, in degrees; This represents the coefficient of friction, which is dimensionless. This indicates the oil / flow velocity, in m / s; Indicates the diameter of the oil pipe, in meters (m).

[0053] The above formula expresses the pressure change of oil and gas due to gravity, friction, and loss of kinetic energy. It is easy to see from the formula that if we want to solve for the pressure, we need to know the density, velocity, friction coefficient, and viscosity of the oil and gas under the current environment. If we want to solve for the density, velocity, friction coefficient, and viscosity, we must know the pressure of the gas under the current environment. Therefore, this formula must be solved iteratively.

[0054] Oil and gas density can be expressed as: ; in, This represents the relative density of oil and gas, and is dimensionless. This represents the average pressure of oil and gas in the selected tubing unit, in MPa; This represents the gas compressibility coefficient corresponding to the average pressure; it is dimensionless. This represents the average temperature of the selected infinitesimal segment, in K.

[0055] The coefficient of friction between oil and gas can be expressed as: ; Therefore: ; in, The absolute roughness of the pipe wall is expressed in meters (m). Represents the Reynolds number, which is dimensionless.

[0056] The calculation of the Reynolds number can be expressed as: ; or: ; in, This indicates the mass flow rate of oil and gas, in kg / d. Indicates the dynamic viscosity of oil and gas, Pa·s; The volumetric flow rate of oil and gas is expressed in m. 3 / d; Indicates the kinematic viscosity of oil and gas, m 2 / s.

[0057] Therefore, the calculation yields: ; in, This represents the pressure loss due to gravity, expressed in MPa. This indicates the starting depth value of the selected micro-element. This indicates the endpoint depth value of the selected micro-element segment.

[0058] ; in, This represents the pressure loss due to friction, expressed in MPa. ; in, The pressure value, expressed in MPa, represents the pressure lost due to kinetic energy.

[0059] Therefore, the oil and gas pressure value at the output end of the micro-element segment can be expressed as: .

[0060] In the above method, it is necessary to solve and calculate the temperature drop of the oil and gas after passing through the throttle valve. The calculation method for this temperature drop is as follows: like Figure 3As shown, during the throttling process, the steady-state flow energy equation yields: ; in, , These represent the changes in enthalpy at the cross-section of the throttle nozzle for a unit mass of oil and gas flowing in and out, respectively. It represents the total heat absorbed by the environment per unit mass of oil or gas. This represents the shaft work done by pressure on the fluid. This indicates the height difference between the inflow and outflow sections.

[0061] According to the steady-state flow energy equation, the enthalpy of the gas remains unchanged before and after the oil and gas throttling and cooling process. Therefore, the differential throttling effect coefficient is: ; Temperature change can be expressed as: ; Since the pressure before and after throttling determines the expansion of oil and gas and its heat absorption capacity, the relationship between temperature and pressure before and after throttling can be approximately expressed as: ; The temperature drop of oil and gas after passing through the throttle valve can be obtained from the above formula.

[0062] Example 2 This embodiment provides a system for evaluating the installation depth of a multi-stage throttle valve, including: The oil well initial data acquisition module is used to obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature ; The wellbore micro-segment construction module is used to construct wellbore micro-segments based on the initial segment of the wellbore of the oil well to be evaluated. The geothermal gradient setting module is used to set the geothermal gradient based on the geological parameters of the location of the oil well to be evaluated. ; The pressure variation setting module is used to preset the pressure variation of a micro-section of the wellbore based on the geological parameters of the location of the well to be evaluated. ; The outlet pressure calculation module is used to calculate the outlet pressure of the corresponding wellbore micro-element section using formula (1). The specific calculation formula is as follows: (1) in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; The pressure deviation calculation module is used to calculate the pressure deviation using formula (2). The specific calculation formula is as follows: (2) The wellhead reach determination module is used to determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has reached the wellhead, it proceeds to the output result module; if it has not reached the wellhead, it proceeds to the error comparison module. The error comparison module is used to determine the pressure deviation. With pressure changes If the error between the two is less than the preset expected error, then proceed to the pre-throttling pressure update module and proceed to the next micro-segment; if it is not less than the expected error, then proceed to the pressure change update module to update the pressure and continue iterating. The pressure change update module is used to calculate the pressure deviation obtained from the pressure deviation calculation module. Replace and update the pressure change setting module's value for the pressure change. Then, it enters the pressure change setting module; The pre-throttling pressure update module is used to update the outlet pressure of the outlet pressure calculation module. Update to pre-throttling pressure, which is used to calculate post-throttling data; The outlet temperature calculation module is used to calculate the outlet temperature of the corresponding wellbore micro-element segment using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: (3); (4); in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure. The throttle valve installation parameter adjustment module is used to adjust the throttle valve installation parameters based on the throttle pressure update module and the outlet temperature calculation module. The installation parameters include the installation depth, the throttle nozzle diameter, whether multi-stage throttling is used, and the number of throttling stages. The post-throttling data calculation module is used to calculate the post-throttling pressure using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: (5); (6) in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; Indicates the diameter of the throttle nozzle, in meters (m). The pressure and temperature replacement module is used to replace the pressure calculated by the post-throttling data calculation module. Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature ; The other throttle valve judgment module is used to determine whether other throttle valves exist; if they exist, the module proceeds to the throttle valve installation parameter adjustment module; if they do not exist, the module proceeds to the outlet pressure calculation module. The output results module is used to evaluate the completion and output the results, including the whole wellbore pressure distribution curve, the whole wellbore temperature distribution curve, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

[0063] Example 3 A computer device includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform steps of a method for evaluating the installation depth of a multi-stage throttle valve.

[0064] The computer device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device can interact with the user via a keyboard, mouse, remote control, touchpad, or voice control.

[0065] The memory includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or D-interface display memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, etc. In some embodiments, the memory may be an internal storage unit of the computer device, such as the hard disk or memory of the computer device. In other embodiments, the memory may also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the computer device. Of course, the memory may include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is often used to store the operating system and various application software installed on the computer device, such as the program code of the evaluation method for the installation depth of the multi-stage throttle valve. In addition, the memory can also be used to temporarily store various types of data that have been output or will be output.

[0066] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of the computer device. In this embodiment, the processor is used to run program code stored in the memory or process data, such as running program code for the evaluation method of the multi-stage throttle valve installation depth.

[0067] Example 4 A computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of a method for evaluating the installation depth of a multi-stage throttle valve.

[0068] The computer-readable storage medium stores an interface display program that can be executed by at least one processor to perform the steps of the multi-stage throttle valve installation depth evaluation method described above.

[0069] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the multi-stage throttle valve installation depth evaluation method described in the embodiments of this application.

Claims

1. A method for evaluating the installation depth of a multi-stage throttle valve, characterized in that, Includes the following steps: Step 1: Obtain initial data for the oil well; Obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature ; Step 2, construct wellbore micro-segments; Construct wellbore micro-segments based on the initial section of the wellbore of the oil well to be evaluated; Step 3, set the geothermal gradient; Geothermal gradients are set based on the geological parameters of the location of the oil well to be evaluated. ; Step 4, set the pressure variation; Based on the geological parameters of the well location to be evaluated, the pressure changes in the pre-set wellbore micro-segments are calculated. ; Step 5: Calculate the outlet pressure; Calculate the outlet pressure of the corresponding wellbore micro-element using formula (1). The specific calculation formula is as follows: （1） in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; Step 6: Calculate the pressure deviation; Calculate the pressure deviation using formula (2) The specific calculation formula is as follows: （2） Step 7: Determine if the wellhead has been reached; Determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has, proceed to step 16; if it has not, proceed to step 8. Step 8, Error Comparison; Determine pressure deviation With pressure changes If the error is less than the preset expected error, proceed to step 10 to reduce pressure; if it is not less, proceed to step 9 to update the pressure and continue iterating. Step 9, update pressure changes; Using the pressure deviation obtained in step 6 Replace and update the pressure change in step 4 with the value. Then proceed to step 4; Step 10, Update the pressure before throttling. The outlet pressure in step 5 Update to pre-throttling pressure, which is used to calculate post-throttling data; Step 11, calculate the outlet temperature; The outlet temperature of the corresponding wellbore micro-element segment is calculated using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: （3）； （4）； in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure. Step 12: Adjust the throttle valve installation parameters; Adjust the throttling valve installation parameters according to the pre-throttling pressure in step 10 and the pre-throttling temperature in step 11. The installation parameters include the installation depth, the throttling nozzle diameter of the throttling valve, whether multi-stage throttling is used, and the number of throttling stages. Step 13, calculate the data after throttling; Calculate the post-throttling pressure using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: （5）； （6） in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; Indicates the diameter of the throttle nozzle, in meters (m). Step 14, replace pressure and temperature; The pressure after throttling calculated in step 13 Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature ; Step 15, determine other throttle valves; Determine if there are other throttle valves; if so, proceed to step 12; if not, proceed to step 5. Step 16, output the result; The evaluation is completed, and the results are output, including the pressure distribution curve of the entire wellbore, the temperature distribution curve of the entire wellbore, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

2. The method for evaluating the installation depth of a multi-stage throttle valve as described in claim 1, characterized in that, In step 5, the pressure value Pressure value Pressure value The calculation formulas are as follows: ； ； ； in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. Indicates the density of oil and gas. Represents gravitational acceleration. Indicates the angle between the pipe and the horizontal line. Indicates the coefficient of friction. Indicates the dynamic viscosity of oil and gas. This indicates the diameter of the oil pipe.

3. The method for evaluating the installation depth of a multi-stage throttle valve as described in claim 2, characterized in that, Oil and gas density The calculation formula is: in, Indicates the relative density of oil and gas; This represents the average pressure of oil and gas in the selected tubing unit, in MPa; This represents the gas compressibility coefficient corresponding to the average pressure; it is dimensionless. This represents the average temperature of the selected micro-element segment.

4. The method for evaluating the installation depth of a multi-stage throttle valve as described in claim 1, characterized in that, In step 7, the criterion for determining whether the end of the current wellbore micro-segment has reached the wellhead is as follows: Determine whether the endpoint depth of the current micro-segment is equal to or exceeds the total wellbore depth; if If the wellhead is reached, it is determined that the wellhead has been reached; otherwise, it is determined that the wellhead has not been reached. in, This indicates the calculation segment length of the current infinitesimal segment. Indicates the total well depth.

5. A system for evaluating the installation depth of a multi-stage throttle valve, characterized in that, include: The oil well initial data acquisition module is used to obtain the initial pressure of the oil well to be evaluated. Well depth H and initial temperature ; The wellbore micro-segment construction module is used to construct wellbore micro-segments based on the initial segment of the wellbore of the oil well to be evaluated. The geothermal gradient setting module is used to set the geothermal gradient based on the geological parameters of the location of the oil well to be evaluated. ; The pressure variation setting module is used to preset the pressure variation of a micro-section of the wellbore based on the geological parameters of the location of the well to be evaluated. ; The outlet pressure calculation module is used to calculate the outlet pressure of the corresponding wellbore micro-element section using formula (1). ; The specific calculation formula is as follows: （1） in, Indicates the initial pressure. This represents the pressure value lost due to gravity. This indicates the pressure value lost due to friction. This represents the pressure value due to kinetic energy loss; The pressure deviation calculation module is used to calculate the pressure deviation using formula (2). The specific calculation formula is as follows: （2） The wellhead reach determination module is used to determine whether the end of the current wellbore micro-segment has reached the wellhead; if it has reached the wellhead, it proceeds to the output result module; if it has not reached the wellhead, it proceeds to the error comparison module. The error comparison module is used to determine the pressure deviation. With pressure changes If the error between the two is less than the preset expected error, then proceed to the pre-throttling pressure update module and proceed to the next micro-segment; if it is not less than the expected error, then proceed to the pressure change update module to update the pressure and continue iterating. The pressure change update module is used to calculate the pressure deviation obtained from the pressure deviation calculation module. Replace and update the pressure change setting module's value for the pressure change. Then, it enters the pressure change setting module; The pre-throttling pressure update module is used to update the outlet pressure of the outlet pressure calculation module. Update to pre-throttling pressure, which is used to calculate post-throttling data; The outlet temperature calculation module is used to calculate the outlet temperature of the corresponding wellbore micro-element segment using formulas (3) and (4). and the outlet temperature Updated to the pre-throttling temperature, which is used to calculate the post-throttling data; the specific calculation formula is as follows: （3）； （4）； in, This indicates the starting depth value of the selected micro-element. This represents the endpoint depth value of the selected micro-element segment. This represents the unit change in oil and gas temperature. This represents the length of a unit tubular element within a micro-element segment. represents the wellbore diameter, Indicates the overall heat transfer coefficient. Indicates the thermal conductivity of the formation. Represents a dimensionless time function. Indicates the number of days. Indicates fluid temperature. Indicates the original temperature of the strata. This represents the Joule-Thomson coefficient. Indicates the pressure gradient. Indicates the coefficient of friction. Indicates the oil and gas flow rate. This indicates the specific heat capacity at constant pressure. The throttle valve installation parameter adjustment module is used to adjust the throttle valve installation parameters based on the throttle pressure update module and the outlet temperature calculation module. The installation parameters include the installation depth, the throttle nozzle diameter, whether multi-stage throttling is used, and the number of throttling stages. The post-throttling data calculation module is used to calculate the post-throttling pressure using formulas (5) and (6). Temperature after throttling The specific calculation formula is as follows: （5）； （6） in, Indicates the adiabatic index of oil and gas. Indicates the relative density of oil and gas. This represents the gas compressibility coefficient at the pressure before throttling; Indicates desired output, m 3 / d; Indicates the diameter of the throttle nozzle, in meters (m). The pressure and temperature replacement module is used to replace the pressure calculated by the post-throttling data calculation module. Temperature after throttling Replace and update the initial pressure for the next wellbore micro-segment. Initial temperature ; The other throttle valve judgment module is used to determine whether other throttle valves exist; if they exist, the module proceeds to the throttle valve installation parameter adjustment module; if they do not exist, the module proceeds to the outlet pressure calculation module. The output results module is used to evaluate the completion and output the results, including the whole wellbore pressure distribution curve, the whole wellbore temperature distribution curve, the pressure and temperature before and after throttling of each throttling valve, whether the flow velocity of the throttling nozzle reaches the critical flow, and the recommended installation parameters for multi-stage throttling valves.

6. A computer device, characterized in that: It includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that: The device stores a computer program that, when executed by a processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 4.

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