A method for making an oil and gas reservoir benefit development property lower limit chart

Abstract

The application discloses a kind of oil and gas reservoir benefit development physical property lower limit chart's making method, specifically includes the following steps: step one, core basic physical property test;Step two, indoor productivity simulation experiment;Step three, establish similarity conversion model;Step four, make benefit development physical property lower limit chart;Step five, use benefit development physical property lower limit chart.The oil and gas reservoir benefit development physical property lower limit chart's making method disclosed in the application takes whether oil and gas reservoir can meet the benefit productivity given under different geological and production conditions as the basis for decision, and the benefit development physical property lower limit comprehensively considers the influence of benefit productivity, production system, reservoir thickness and production well type and multiple factors, compared with the effective reservoir physical property lower limit with oil and gas flow as the basis for decision, the field application value in oil and gas field development stage is higher.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method for producing a lower limit chart of physical properties for efficient oil and gas reservoir development. Background Technology

[0002] Reserves and production capacity are crucial parameters for evaluating the development value of oil and gas reservoirs. Reserves are the foundation for effective oil and gas field development, while production capacity is key to ensuring profitable development. During the exploration and development phases of oil and gas fields, engineers use various technical means to assess and predict both effective movable reserves and profitable movable reserves. Effective movable reserves are judged based on the flowability of oil and gas within the reservoir, while profitable movable reserves are evaluated based on whether the flow velocity of oil and gas within the reservoir can reach the minimum production capacity required for profitable development. Among these, the lower limit of physical properties for profitable development is the most critical parameter in calculating profitable movable reserves, including the lower limit values ​​for porosity and permeability. The lower limit of porosity ensures that the oil and gas reservoir possesses reserves suitable for profitable development during the exploration phase, while the lower limit of permeability ensures that the oil and gas reservoir can meet the required production capacity during the development phase. Unlike the effective reservoir physical property lower limit, which is a fixed set of porosity and permeability values, the porosity and permeability values ​​of the profitable development physical property lower limit are related to multiple factors such as profitable production capacity, production system, effective reservoir thickness and production well type, and are a set of dynamically changing parameters.

[0003] Therefore, creating a chart that considers multiple factors is of significant application value for quickly and accurately determining the lower limits of economically viable physical properties for different reservoir properties and production conditions. However, the key technology of this invention patent lies in how to create such a chart of lower limits of economically viable physical properties for oil and gas reservoirs, given the scarcity of dynamic production data in the early stages of oil and gas field development, using limited field data and relevant research methods. Research has revealed that there is currently no method for creating such a chart. Summary of the Invention

[0004] This invention discloses a method for producing a lower limit chart of physical properties for the efficient development of oil and gas reservoirs, aiming to solve the technical problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for creating a lower limit chart of physical properties for efficient development of oil and gas reservoirs, specifically including the following steps:

[0007] Step 1: Core basic physical property testing; A large number of natural reservoir cores from multiple oil and gas wells in the study area were selected. After the cores were numbered and pre-processed, basic physical property tests of porosity, permeability, length and diameter were carried out in sequence. The measurement data were recorded. A scatter plot of the porosity-permeability relationship was plotted using the core porosity and permeability data. The porosity-permeability relationship formula was obtained by fitting. Based on the range of porosity and permeability values, multiple porosity-permeability distribution areas were divided.

[0008] Step 2, Indoor Production Capacity Simulation Experiment: Multiple core samples were selected from different pore-permeability distribution areas obtained in Step 1 to conduct indoor production capacity simulation experiments. A high-temperature and high-pressure core displacement physical simulation experimental platform was built. The experimental process completely simulated the temperature and pressure conditions and fluid properties of the oil and gas reservoir. By applying a gradually increasing displacement pressure difference at both ends of the core sample, the stable oil and gas flow rate under each displacement pressure difference was measured, and the displacement pressure difference and oil and gas flow rate data of core samples with different physical properties were recorded.

[0009] Step 3: Establish a similarity conversion model. Assuming that the fluid velocity at the bottom of the oil and gas well is equal to the fluid velocity at the core outlet, establish a similarity conversion model between the displacement pressure difference and oil and gas flow rate in the production simulation experiment and the production pressure difference and daily oil and gas production of the well in the field. Use the production index ratio to equivalently represent the production capacity of vertical and horizontal wells, and establish a similarity conversion model between the daily oil and gas production of vertical wells and the daily oil and gas production of horizontal wells. Using this similarity conversion model, convert the displacement pressure difference and oil and gas flow rate data of cores with different physical properties obtained in Step 2 into production pressure difference and daily oil and gas production data of vertical and horizontal wells in reservoirs with different physical properties.

[0010] Step 4: Create a lower limit map of the physical properties for efficient development. Select porosity or permeability as representative of reservoir properties. Import the data on the relationship between reservoir properties, production pressure difference, and oil and gas production obtained in Step 3 into Surfer software. Use Kriging interpolation to convert discontinuous data into continuous data. Use the field map drawing function of Surfer software to create a lower limit map of the physical properties for efficient development that considers multiple factors, with reservoir properties as the x-axis, production pressure difference as the y-axis, and oil and gas production per unit reservoir thickness as contour lines.

[0011] Step 5: Use the lower limit chart of physical properties for efficient development; combine the actual situation of the oil and gas field with international oil and gas prices to determine the minimum oil and gas production to meet the requirements of efficient development; determine the average thickness of the reservoir in the study area using geophysical methods; clarify the production pressure difference of oil and gas wells according to the oil and gas field development plan; and obtain various parameters of oil and gas wells by referring to the well type design and construction plan. Find the only point in the lower limit chart of physical properties for efficient development that simultaneously meets the above factors. The physical property value corresponding to this point is the lower limit value of porosity or permeability. Substitute this value into the porosity-permeability relationship obtained in Step 1 to obtain the corresponding lower limit value of permeability or porosity.

[0012] In a preferred embodiment, the core basic physical property testing in step one includes the following steps: Step 1.1: Drill natural full-diameter cores from multiple oil and gas wells in the study area and prepare standard plunger cores of φ25.4mm×50mm; register and number these cores and record the well number, stratigraphic position, and depth of the cores; Step 1.2: After preprocessing the large number of natural cores obtained in step 1.1, measure and record the basic physical properties of porosity, permeability, length, diameter, and mass; Step 1.3: Based on the core basic physical property data obtained in step 1.2, plot a logarithmic coordinate scatter plot with porosity as the abscissa and the logarithm of permeability as the ordinate; fit the porosity and permeability scatter plot data to obtain the porosity-permeability relationship curve and the porosity-permeability relationship formula; divide the scatter plot into multiple physical property regions according to the distribution range of core porosity and permeability.

[0013] In a preferred embodiment, the indoor production capacity simulation experiment in step two includes the following steps: Step 2.1: Construct a high-temperature and high-pressure core displacement experimental platform according to the experimental device flowchart. This platform consists of a pressurization system, an injection system, a core system, and a metering system. The pressurization system mainly includes gas cylinders and a pressurization pump; the injection system mainly includes a dual-cylinder displacement pump and an intermediate container; the core system mainly includes a core holder, a pressure sensor, a temperature sensor, an electric heating jacket, a confining pressure pump, a back pressure pump, a back pressure valve, and a six-way valve; the metering system mainly includes a separation device, an electronic flow meter, an automatic data metering device, and a computer; Step 2.2: Select multiple cores from the various physical property regions defined in step 1.3 and place them in the high-temperature and high-pressure core displacement experimental platform to prepare for the production capacity simulation experiment; the experimental temperature and pressure are set according to the actual temperature and pressure conditions of the oil and gas reservoir, and the oil, gas, and water samples used in the experiment are all taken from the actual oil and gas reservoir; design multiple core displacement pressure differences from low to high as ΔP1, ΔP2, ΔP3, ... ΔP n Step 2.3: During the experiment, the temperature, confining pressure, and flowing pressure of the core were raised to the set values ​​using an electric heating jacket, a confining pressure pump, and a displacement pump, respectively. Then, the pressure of the confining pressure pump and the displacement pump were kept constant, and the back pressure was gradually reduced using a back pressure pump to simulate the gradually increasing displacement pressure difference of the core. The oil and gas flow rate was measured every 5 minutes under each displacement pressure difference. When the difference between three consecutive flow rate measurements was less than 5%, the flow rate under that displacement pressure difference was considered to have reached stability. Step 2.4: The stable flow rate of each core under different displacement pressure differences was recorded, where the stable flow rate was the average of the last three measurements.

[0014] In a preferred embodiment, step three, establishing the similarity conversion model, includes the following steps: Step 3.1: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similarity conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the vertical well in the field; Step 3.2: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similarity conversion model between the oil and gas flow rate at the core outlet and the daily oil and gas production of the vertical well in the field; Step 3.3: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similarity conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the horizontal well in the field; Step 3.4: Define the production index ratio J. r For the same gas supply area and production pressure differential, the horizontal well production index J h With vertical well production index J v The ratio is used to establish a similarity conversion model for the daily oil and gas production of vertical wells and horizontal wells in the mining area; Step 3.5: For vertical wells, using the similarity conversion formula for vertical well pressure difference established in Step 3.1 and the similarity conversion formula for vertical well production established in Step 3.2, the displacement pressure difference and oil and gas flow rate data of different physical property cores recorded in Step 2.4 are converted into the production pressure difference and daily oil and gas production of vertical wells in reservoirs with different physical properties, respectively; Step 3.6: For horizontal wells, using the similarity conversion formula for horizontal well pressure difference established in Step 3.3 and the similarity conversion formula for horizontal well production established in Step 3.4, the displacement pressure difference of different physical property cores recorded in Step 2.4 and the daily oil and gas production data of vertical wells obtained in Step 3.5 are converted into the production pressure difference and daily oil and gas production of horizontal wells in reservoirs with different physical properties, respectively.

[0015] In a preferred embodiment, step four, creating the lower limit chart of physical properties for efficient development, includes the following steps: Step 4.1: Experimental data points obtained from core samples with different physical properties under different displacement pressure differentials are limited and cannot cover the entire range of physical properties of oil and gas reservoirs or simulate all displacement pressure differentials. Based on the production pressure differential and daily oil and gas production of horizontal wells in reservoirs with different physical properties obtained in step 3.6, a permeability-pressure differential-production data table is created and imported into Surfer software; Step 4.2: In the Surfer software menu bar, select "Grid," and in the "Grid" drop-down menu, select "Data." Select permeability for the X-axis data, production pressure differential for the Y-axis data, and daily production capacity for the Z-column data. Set the minimum value of the X-column to 0, and the maximum value of the X-column to K based on the maximum permeability of the core sample. max The minimum value in column Y is set to 0, and the maximum value in column Y is set to ΔP based on the maximum production pressure difference. maxThe network algorithm selected is "Kriging interpolation". The process of importing basic data and exporting the grid file is completed. Step 4.3: In the Surfer software menu bar, select "Grid" and then "Mathematics" from the drop-down menu. Add the grid file exported in Step 4.2, and select column C corresponding to the production capacity in the Excel data table in "Variable Name". Then enter the formula C = max(C, 0) and export the grid file again. This formula means that the data in column C is compared with 0, and the larger value is used to replace the data in column C to eliminate negative numbers. Step 4.4: In the Surfer software menu bar, select "Graphics" and then "New Contour Map" from the drop-down menu. Then import the grid file obtained in Step 4.3. Process the obtained contour map, including the scaling ratio of the coordinate axes, the interval of the scale values, the position of the scale values, and the contour interval, fill color, transparency, and ratio of the graph. Example; Step 4.5: In the Surfer software menu bar, select "File," and in the "File" drop-down menu, select "Export." Then, in the save type, select "JPG JPEG Compressed Bitmap," and check "Maintain Aspect Ratio" and "Maintain Pixel Density." This will export the lower limit map of economic development properties drawn in Step 4.4 as a high-resolution image. Step 4.6: Surfer software cannot set numbers less than 1 on the axes, nor can it label the units of the axes. Therefore, the units of the axes in the lower limit map of economic development properties exported in Step 4.5 need to be edited. Since the production pressure differential of oil and gas wells is generally controlled within 0–100 MPa, the vertical axis unit needs to be set to MPa. The permeability of high-permeability oil and gas reservoirs is generally greater than 1 mD, so the horizontal axis unit needs to be set to mD. The permeability of low-permeability oil and gas reservoirs is partially less than 1 mD, so the horizontal axis unit needs to be set to 10. -1 Or 10 -2 mD; Step 4.7: After setting the units of the horizontal and vertical axes, the lower limit chart of the physical properties for the benefit development of horizontal wells is completed. The lower limit chart of the physical properties for the benefit development of vertical wells can be made by referring to Step 4.1 to Step 4.6 using the vertical well production pressure difference and daily output data statistically obtained in Step 3.5.

[0016] In a preferred embodiment, step five, using the lower limit map of efficient development properties, includes the following steps: Step 5.1: Based on the actual conditions of the oilfield and international oil and gas prices, determine the daily production rate of oil and gas that meets the needs of efficient oil and gas field development. Then, determine the average thickness of the oil and gas reservoir in the study area using geophysical methods, and calculate the efficient daily production rate per unit reservoir thickness; Step 5.2: Determine the production pressure differential of oil and gas wells according to the oil and gas field development plan of the study area; determine various parameters of oil and gas wells with reference to well type design and construction plan, and select the lower limit map of efficient development properties corresponding to the well type and well parameters; Step 5.3: Based on the efficient daily production rate per unit reservoir thickness of oil and gas wells determined in step 5.1, find and select the contour line corresponding to its value in the lower limit map of efficient development properties; based on the determination in step 5.2... Given a fixed production pressure differential, find point A on the vertical axis of the lower limit map of efficient development properties, and draw a horizontal line from point A to the selected contour line, intersecting it at point B. Draw a perpendicular line from point B to the horizontal axis, intersecting it at point C. The permeability value corresponding to point C is the lower limit permeability value for the oil and gas field to meet the required efficient production capacity. Step 5.4: Substitute the lower limit permeability value obtained in step 5.3 into the porosity-permeability relationship established in step 1.3 to calculate the lower limit porosity value. By changing the efficient production capacity and reservoir thickness in step 5.1, and changing the production pressure differential and production well type in step 5.2, a series of lower limit values ​​of efficient development properties under the influence of multiple factors can be obtained, providing a theoretical basis for calculating the efficient movable reserves of oil and gas fields and formulating drilling and production plans.

[0017] The method for producing the lower limit chart of oil and gas reservoir property for efficient development provided by this invention has the following technical effects:

[0018] (1) The lower limit of the physical properties for efficient development is based on whether the oil and gas reservoir can meet the given efficient production capacity under different geological and production conditions. Compared with the lower limit of the physical properties of effective reservoirs based on whether the oil and gas are flowing, it has higher field application value in the oil and gas field development stage.

[0019] (2) The lower limit of physical properties for efficient development comprehensively considers the influence of multiple factors such as efficient production capacity, production system, reservoir thickness and production well type on the lower limit of physical properties, thus overcoming the defect that the lower limit of physical properties for effective reservoirs cannot take into account the above factors.

[0020] (3) The lower limit of physical properties for efficient development was determined by conducting physical simulation experiments on actual reservoir cores in the laboratory and combining them with the mathematical model of similarity conversion that was independently established. This solved the problems of lack of production dynamic data and high cost of field tests in the early stage of oil and gas field development.

[0021] (4) The physical simulation experimental data after similarity conversion were interpolated using the interpolation and field map drawing functions of Surfer software. Then, a lower limit chart of physical properties for benefit development considering multiple factors was drawn, which further improved the applicability and efficiency of the lower limit of physical properties. The corresponding lower limit value of physical properties for benefit development can be found by giving different benefit production capacity, production pressure difference, reservoir thickness and production well type data.

[0022] Therefore, this invention provides a theoretical basis for the accurate assessment of the beneficial reserves of oil and gas reservoirs, as well as the efficient formulation of drilling and development plans. Attached Figure Description

[0023] Figure 1 This is a flowchart of a high-temperature, high-pressure core displacement experimental platform for a method of creating a lower limit map of the physical properties for efficient oil and gas reservoir development proposed in this invention.

[0024] Figure 2 This is a data recording table of production capacity simulation experiments for a method of creating a lower limit chart of physical properties for efficient development of oil and gas reservoirs proposed in this invention.

[0025] Figure 3 This is a pressure difference and production similarity conversion data table for a method of creating a lower limit map of the physical properties for efficient development of oil and gas reservoirs proposed in this invention.

[0026] Figure 4 This invention provides a permeability-pressure difference-production capacity data table for a method of creating a lower limit chart of physical properties for efficient oil and gas reservoir development.

[0027] Figure 5 This is an example of a diagram illustrating the lower limit of physical properties for the efficient development of oil and gas reservoirs proposed in this invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Reference Figure 1-5 A method for creating a lower limit chart of physical properties for efficient development of oil and gas reservoirs, specifically including the following steps:

[0030] Step 1: Core basic physical property testing; A large number of natural reservoir cores from multiple oil and gas wells in the study area were selected. After the cores were numbered and pre-processed, basic physical property tests of porosity, permeability, length and diameter were carried out in sequence. The measurement data were recorded. A scatter plot of the porosity-permeability relationship was plotted using the core porosity and permeability data. The porosity-permeability relationship formula was obtained by fitting. Based on the range of porosity and permeability values, multiple porosity-permeability distribution areas were divided.

[0031] Step 2, Indoor Production Capacity Simulation Experiment: Multiple core samples were selected from different pore-permeability distribution areas obtained in Step 1 to conduct indoor production capacity simulation experiments. A high-temperature and high-pressure core displacement physical simulation experimental platform was built. The experimental process completely simulated the temperature and pressure conditions and fluid properties of the oil and gas reservoir. By applying a gradually increasing displacement pressure difference at both ends of the core sample, the stable oil and gas flow rate under each displacement pressure difference was measured, and the displacement pressure difference and oil and gas flow rate data of core samples with different physical properties were recorded.

[0032] Step 3: Establish a similarity conversion model. Assuming the fluid velocity at the bottom of the oil and gas well is equal to the fluid velocity at the core outlet, establish a similarity conversion model between the displacement pressure differential and oil and gas flow rate from the production simulation experiment and the production pressure differential and daily oil and gas production of the well in the production field. Using the production index ratio to equivalently represent the production capacity of vertical and horizontal wells, establish a similarity conversion model for the daily oil and gas production of vertical and horizontal wells. Using this similarity conversion model, convert the displacement pressure differential and oil and gas flow rate data of cores with different physical properties obtained in Step 2 into production pressure differential and daily oil and gas production data for vertical and horizontal wells in reservoirs with different physical properties.

[0033] Step 4: Create a lower limit map of reservoir properties for efficient development. Select porosity or permeability as representative reservoir properties. Import the relationship data between reservoir properties, production pressure difference, and oil and gas production obtained in Step 3 into Surfer software. Use Kriging interpolation to convert discontinuous relationship data into continuous data. Then, use the field map drawing function of Surfer software to create a lower limit map of reservoir properties for efficient development that considers multiple factors, with reservoir properties as the x-axis, production pressure difference as the y-axis, and oil and gas production per unit reservoir thickness as contour lines.

[0034] Step 5: Use the lower limit chart of physical properties for efficient development; combine the actual situation of the oil and gas field with international oil and gas prices to determine the minimum oil and gas production to meet the requirements of efficient development; determine the average thickness of the reservoir in the study area using geophysical methods; clarify the production pressure difference of oil and gas wells according to the oil and gas field development plan; and obtain various parameters of oil and gas wells by referring to the well type design and construction plan. Find the only point in the lower limit chart of physical properties for efficient development that simultaneously meets the above factors. The physical property value corresponding to this point is the lower limit value of porosity or permeability. Substitute this value into the porosity-permeability relationship obtained in Step 1 to obtain the corresponding lower limit value of permeability or porosity.

[0035] In a preferred embodiment, the core basic physical property testing in step one includes the following steps:

[0036] Step 1.1: Drill natural full-diameter cores from multiple oil and gas wells in the study area and prepare standard plunger cores with a diameter of φ25.4mm×50mm; register and number these cores and record the well number, stratigraphic position, and depth of the cores;

[0037] Step 1.2: After preprocessing the large number of natural rock cores obtained in Step 1.1, measure and record the basic physical properties such as porosity, permeability, length, diameter and mass.

[0038] Step 1.3: Based on the core basic physical property data obtained in Step 1.2, plot a logarithmic coordinate scatter plot with porosity as the abscissa and the logarithm of permeability as the ordinate; fit the porosity and permeability scatter plot data to obtain the porosity-permeability relationship curve and the porosity-permeability relationship formula; divide the scatter plot into multiple physical property regions according to the distribution range of core porosity and permeability.

[0039] In a preferred embodiment, the indoor production capacity simulation experiment in step two includes the following steps:

[0040] Step 2.1: Construct a high-temperature and high-pressure core displacement experimental platform according to the experimental setup flowchart. This platform consists of a pressurization system, an injection system, a core system, and a metering system. The pressurization system mainly includes gas cylinders and a pressurization pump; the injection system mainly includes a dual-cylinder displacement pump and an intermediate container; the core system mainly includes a core holder, a pressure sensor, a temperature sensor, an electric heating jacket, a confining pressure pump, a back pressure pump, a back pressure valve, and a six-way valve; the metering system mainly includes a separation device, an electronic flow meter, an automatic data metering device, and a computer.

[0041] Step 2.2: Select multiple core samples from the various physical property regions defined in Step 1.3 and place them in the high-temperature and high-pressure core displacement experimental platform to prepare for a production capacity simulation experiment. The experimental temperature and pressure are set according to the actual temperature and pressure conditions of oil and gas reservoirs. The oil, gas, and water samples used in the experiment are all taken from actual oil and gas reservoirs. Design multiple core displacement pressure differentials from low to high as ΔP1, ΔP2, ΔP3, ... ΔP n ;

[0042] Step 2.3: During the experiment, the temperature, confining pressure, and flowing pressure of the core were raised to the set values ​​using an electric heating jacket, a confining pressure pump, and a displacement pump, respectively. Then, the pressure of the confining pressure pump and the displacement pump were kept constant, and the back pressure was gradually reduced using a back pressure pump to simulate the gradually increasing core displacement pressure difference. The oil and gas flow rate was measured every 5 minutes under each displacement pressure difference. When the difference between three consecutive flow rate measurements was less than 5%, the flow rate under that displacement pressure difference was considered to have reached stability.

[0043] Step 2.4: Record the steady-state flow rate of each core sample under different displacement pressure differentials. The steady-state flow rate is the average of the last three measurements. The data recording table is attached. Figure 2 As shown.

[0044] In a preferred embodiment, step three, establishing the similarity conversion model, includes the following steps:

[0045] Step 3.1: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the vertical well in the field.

[0046] Step 3.2: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the oil and gas flow rate at the core outlet and the daily oil and gas production of the vertical well in the field.

[0047] Step 3.3: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the horizontal well in the field.

[0048] Step 3.4: Define the production index ratio J r For the same gas supply area and production pressure differential, the horizontal well production index J h With vertical well production index J v Based on the ratio, a similarity conversion model is established between the daily oil and gas production of vertical wells and the daily oil and gas production of horizontal wells in the mining area;

[0049] Step 3.5: For vertical well types, using the vertical well pressure difference similarity conversion formula established in Step 3.1 and the vertical well production similarity conversion formula established in Step 3.2, the displacement pressure difference and oil and gas flow rate data of different physical property cores recorded in Step 2.4 are converted into the production pressure difference and daily oil and gas production of vertical wells in reservoirs with different physical properties.

[0050] Step 3.6: For horizontal well types, using the horizontal well pressure difference similarity conversion formula established in Step 3.3 and the horizontal well production similarity conversion formula established in Step 3.4, the displacement pressure difference of core samples with different physical properties recorded in Step 2.4 and the daily oil and gas production data of vertical wells obtained in Step 3.5 are respectively converted into the production pressure difference and daily oil and gas production of horizontal wells in reservoirs with different physical properties. The data conversion record table is attached. Figure 3 As shown.

[0051] In a preferred embodiment, step four, creating the lower limit chart of the benefit development properties, includes the following steps:

[0052] Step 4.1: The experimental data points obtained from core samples with different physical properties under different displacement pressure differentials are limited and cannot cover the entire range of oil and gas reservoir physical properties or simulate all displacement pressure differentials. Therefore, based on the pressure differential and production similarity conversion data table prepared in Step 3.6, one parameter, either permeability or porosity, is used to represent the reservoir physical property. The daily production of vertical or horizontal wells is divided by the reservoir thickness to account for the influence of reservoir thickness. Then, Excel software is used to create the data as shown in the attached table. Figure 4The table shown is a permeability-pressure differential-production data table. This table uses permeability to represent reservoir properties and takes the production pressure differential and daily production capacity of a horizontal well as an example.

[0053] Step 4.2: In the Surfer software's menu bar, select "Grid," and in the "Grid" drop-down menu, select "Data." Then select the attachment created in Step 4.1. Figure 4 The X-column data is selected as permeability, the Y-column data as production pressure differential, and the Z-column data as daily production capacity. The minimum value in the X-column is set to 0, and the maximum value in the X-column is set to K based on the maximum permeability of the core sample. max The minimum value in column Y is set to 0, and the maximum value in column Y is set to ΔP based on the maximum production pressure difference. max The network algorithm selected was Kriging interpolation, which completed the import of basic data and export of grid files. Kriging interpolation assigns different weights to each sample grade based on its spatial location and the degree of correlation between samples, performing a moving weighted average to estimate the average grade of the central block. This method considers not only the relationship between the location of the point to be estimated and the location of known data, but also the spatial correlation of variables. Compared with other types of interpolation methods, Kriging interpolation is more suitable for oil and gas fields and has better applicability to variables obtained through experiments.

[0054] Step 4.3: To solve the problem of negative numbers during interpolation, select "Grid" in the menu bar of the Surfer software, and then select "Mathematics" in the drop-down menu. Add the grid file exported in Step 4.2, and select column C corresponding to the production capacity in the Excel data table in "Variable Name". Then enter the formula C = max(C, 0) and export the grid file again. The meaning of this formula is to compare the data in column C with 0, and replace the data in column C with the larger value.

[0055] Step 4.4: In the Surfer software, select "Graphics" in the menu bar, and then select "New Contour Map" in the "Graphics" drop-down menu. Then import the grid file obtained in Step 4.3. Process the obtained contour map, including the scaling of the coordinate axes, the interval of the scale values, the position of the scale values, as well as the contour interval, fill color, transparency, and scale bar of the graph.

[0056] Step 4.5: In the Surfer software, select "File" in the menu bar, and then select "Export" in the "File" drop-down menu. In the save type, select "JPG JPEG Compressed Bitmap", and check "Preserve Aspect Ratio" and "Preserve Pixel Density" to export the benefit development property lower limit map drawn in Step 4.4 as a high-definition image.

[0057] Step 4.6: Surfer software cannot set numbers less than 1 on the coordinate axes, nor can it label the units of the coordinate axes. The coordinate axis units of the lower limit chart of the benefit development properties exported in Step 4.5 need to be edited. Since the production pressure differential of oil and gas wells is generally controlled within 0–100 MPa, the vertical axis unit needs to be set to MPa; the permeability of high-permeability oil and gas reservoirs is generally greater than 1 mD, so the horizontal axis unit needs to be set to mD; the permeability of low-permeability oil and gas reservoirs is partially less than 1 mD, so the horizontal axis unit needs to be set to 10. -1 Or 10 -2 mD. For example, when the minimum permeability is 0.01 mD, the unit of the horizontal axis should be set to 10. - 2 mD, the smallest scale value on the horizontal axis is still 1.

[0058] Step 4.7: After setting the units for the horizontal and vertical axes, the lower limit chart of the physical properties for the benefit development of horizontal wells is completed. The lower limit chart of the physical properties for the benefit development of vertical wells can be made by referring to steps 4.1 to 4.6 using the vertical well production pressure difference and daily output data collected in step 3.5.

[0059] In a preferred embodiment, step five, using the benefit development property lower limit chart, includes the following steps:

[0060] Step 5.1: Based on the actual conditions of the mining area and international oil and gas prices, determine the daily production capacity of oil and gas that meets the needs of efficient oil and gas field development. Then, determine the average thickness of the oil and gas reservoir in the study area using geophysical methods, and calculate the daily production capacity per unit reservoir thickness.

[0061] Step 5.2: Determine the production pressure differential of oil and gas wells according to the oil and gas field development plan of the study area; determine various parameters of oil and gas wells with reference to well type design and construction plan, and select the lower limit chart of the physical properties for the benefit development of the corresponding well type (vertical well or horizontal well) and well parameters (horizontal section length, etc.);

[0062] Step 5.3: Based on the daily production per unit reservoir thickness of the oil and gas well determined in Step 5.1, find and select the contour line corresponding to its value on the lower limit map of efficient development properties; according to the production pressure difference determined in Step 5.2, find point A on the vertical axis of the lower limit map of efficient development properties, and draw a horizontal line from point A to the selected contour line, intersecting it at point B; draw a perpendicular line from intersection point B to the horizontal axis, intersecting it at point C. The permeability value corresponding to point C is the lower limit permeability value for the oil and gas field to meet the efficient production capacity.

[0063] Step 5.4: Substitute the lower limit value of permeability obtained in Step 5.3 into the porosity-permeability relationship established in Step 1.3 to calculate the lower limit value of porosity. By changing the efficiency production capacity and reservoir thickness in Step 5.1, and changing the production pressure differential and production well type in Step 5.2, a series of lower limit values ​​of efficient development properties under the influence of multiple factors can be obtained, providing a theoretical basis for calculating the efficient movable reserves of oil and gas fields and formulating drilling and production plans.

[0064] In a preferred embodiment, in step 3.1, the model establishment method takes a vertical well in a gas reservoir as an example, and the formula for the gas velocity at the core outlet under Darcy's law experimental conditions is as follows: The formula for the gas velocity at the bottom of a vertical well under mining conditions is: Since the study focuses on the gas flow velocity at the core outlet and the bottom of the gas well, we can set p = p in the first formula. w1 In the second formula, p = p w2 , r = r w Based on the assumptions, let υ sg =υ vg After simplification, the pressure p at the core outlet can be obtained. w1 Pressure p at the bottom of the vertical well w2 Similarity transformation model between:

[0065] The experimental displacement pressure differential and the vertical well production pressure differential can be expressed as Δp, respectively. s =p e -p w1 and Δp v =p e -p w2 ;

[0066] In the formula, K is the reservoir permeability, mD; μ is the gas viscosity, mPa·s; p w1 The pressure at the core outlet is MPa; p w2 The bottom hole pressure of the vertical well is in MPa; p e p is the pressure at the core inlet or the supply pressure at the gas well boundary, in MPa; p is the pressure at any point in the reservoir, in MPa; L is the core length, in m; r e r is the radius of the gas well control area, in meters (m). w denoted as the radius of the gas wellbore, in meters; r is the distance from any point in the reservoir to the bottom of the well, in meters; based on the reservoir and gas well data and core physical property data of the study area, the relevant parameters are substituted into the vertical well pressure difference similarity conversion model to establish the conversion formula between the experimental displacement pressure difference and the gas reservoir vertical well production pressure difference.

[0067] In step 3.2, the model establishment method takes a vertical well in a gas reservoir as an example. The formula for the gas velocity at the core outlet in the experiment is: The formula for the gas velocity at the bottom of the well under mining conditions is: Based on the assumptions, let υ sg =υ rg After simplification, the oil and gas flow rate p at the core outlet can be obtained. w1 Daily gas production p of vertical wells w2 Similarity transformation model between:

[0068] In the formula Q vg For the daily gas production of a vertical well, 10 4 m 3 / d;Q R The gas flow rate at the core outlet is m. 3 / s;r w Where is the wellbore radius (m); h is the reservoir thickness (m); and D is the core diameter (m). Based on the reservoir and gas well data and the basic physical property data of the core in the study area, the relevant parameters are substituted into the vertical well production similarity conversion model to establish the conversion formula between the oil and gas flow rate at the core outlet and the daily oil and gas production of the vertical well in the gas reservoir.

[0069] In a preferred embodiment, in step 3.3, the model establishment method takes a horizontal well in a gas reservoir as an example, based on Darcy's law and the formula for the gas velocity at the core outlet. And the improved Joshi horizontal well bottom hole gas velocity formula The obtained core outlet pressure p w1 Pressure p at the bottom of the horizontal well w3 The similarity transformation model between them is: The experimental displacement pressure differential and the vertical well production pressure differential can be expressed as Δp, respectively. s =p e -p w1 and Δp v =p e -p w3 ;

[0070] In the formula, p w3 For horizontal well bottom hole pressure, MPa; L h The length of the horizontal section of the horizontal well is in meters (m); r wh Where is the radius of the horizontal wellbore, in meters; and T is the reservoir temperature, in kilometer markers. Here, is the gas deviation factor; 'a' is the major axis of the horizontal well ellipse, expressed as: In the formula r eh Let be the control radius of the horizontal well, in meters. Based on the reservoir and gas well data and core physical property data of the study area, relevant parameters are substituted into the horizontal well pressure difference similarity conversion model to establish the conversion formula between the experimental displacement pressure difference and the production pressure difference of the gas reservoir horizontal well.

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing a lower limit chart of physical properties for the efficient development of oil and gas reservoirs, characterized in that, Specifically, the following steps are included: Step 1: Basic physical property testing of core samples; A large number of natural reservoir core samples from multiple oil and gas wells in the study area were selected, numbered and pre-processed, and then basic physical property tests of porosity, permeability, length and diameter were carried out in sequence. The measurement data were recorded and compiled. A scatter plot of the porosity-permeability relationship was plotted using the core porosity and permeability data, and the porosity-permeability relationship formula was obtained by fitting. Based on the range of porosity and permeability values, multiple porosity-permeability distribution areas were divided. Step 2, Indoor Production Capacity Simulation Experiment: Multiple core samples were selected from different pore-permeability distribution areas obtained in Step 1 to conduct indoor production capacity simulation experiments. A high-temperature and high-pressure core displacement physical simulation experimental platform was built. The experimental process completely simulated the temperature and pressure conditions and fluid properties of the oil and gas reservoir. By applying a gradually increasing displacement pressure difference at both ends of the core sample, the stable oil and gas flow rate under each displacement pressure difference was measured, and the displacement pressure difference and oil and gas flow rate data of core samples with different physical properties were recorded. Step 3: Establish a similarity conversion model. Assuming that the fluid velocity at the bottom of the oil and gas well is equal to the fluid velocity at the core outlet, establish a similarity conversion model between the displacement pressure difference and oil and gas flow rate in the production simulation experiment and the production pressure difference and daily oil and gas production of the well in the field. Use the production index ratio to equivalently represent the production capacity of vertical and horizontal wells, and establish a similarity conversion model between the daily oil and gas production of vertical wells and the daily oil and gas production of horizontal wells. Using this similarity conversion model, convert the displacement pressure difference and oil and gas flow rate data of cores with different physical properties obtained in Step 2 into production pressure difference and daily oil and gas production data of vertical and horizontal wells in reservoirs with different physical properties. Step 4: Create a chart showing the lower limit of physical properties for benefit development; Porosity or permeability is selected as a representative of reservoir properties. The relationship data between reservoir properties, production pressure difference and oil and gas production obtained in step 3 is imported into Surfer software. Kriging interpolation is used to convert discontinuous relationship data into continuous data. Using the field map drawing function of Surfer software, a lower limit map of the benefit development properties considering multiple factors is created with reservoir properties as the abscissa, production pressure difference as the ordinate, and oil and gas production per unit reservoir thickness as the contour lines. Step 5: Use the lower limit chart of physical properties for efficient development; combine the actual situation of the oil and gas field with international oil and gas prices to determine the minimum oil and gas production to meet the requirements of efficient development; determine the average thickness of the reservoir in the study area using geophysical methods; clarify the production pressure difference of oil and gas wells according to the oil and gas field development plan; and obtain various parameters of oil and gas wells by referring to the well type design and construction plan. Find the only point in the lower limit chart of physical properties for efficient development that simultaneously meets the above factors. The physical property value corresponding to this point is the lower limit value of porosity or permeability. Substitute this value into the porosity-permeability relationship obtained in Step 1 to obtain the corresponding lower limit value of permeability or porosity.

2. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 1, characterized in that, The core basic physical property testing in step one includes the following steps: Step 1.1: Drill natural full-diameter cores from multiple oil and gas wells in the study area and prepare standard plunger cores with a diameter of φ25.4mm×50mm; register and number these cores and record the well number, stratigraphic position, and depth of the cores; Step 1.2: After preprocessing the large number of natural rock cores obtained in Step 1.1, the porosity, permeability, length, diameter and mass properties are measured and recorded respectively; Step 1.3: Based on the core basic physical property data obtained in Step 1.2, plot a logarithmic coordinate scatter plot with porosity as the abscissa and the logarithm of permeability as the ordinate; fit the porosity and permeability scatter plot data to obtain the porosity-permeability relationship curve and the porosity-permeability relationship formula; divide the scatter plot into multiple physical property regions according to the distribution range of core porosity and permeability.

3. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 2, characterized in that, The indoor production capacity simulation experiment in step two includes the following steps: Step 2.1: Construct a high-temperature and high-pressure core displacement experimental platform according to the experimental setup flowchart. This platform consists of a pressurization system, an injection system, a core system, and a metering system. The pressurization system mainly includes gas cylinders and a pressurization pump; the injection system mainly includes a dual-cylinder displacement pump and an intermediate container; the core system mainly includes a core holder, a pressure sensor, a temperature sensor, an electric heating jacket, a confining pressure pump, a back pressure pump, a back pressure valve, and a six-way valve; the metering system mainly includes a separation device, an electronic flow meter, an automatic data metering device, and a computer. Step 2.2: Select multiple core samples from the various physical property regions defined in Step 1.3 and place them in the high-temperature and high-pressure core displacement experimental platform to prepare for a production capacity simulation experiment. The experimental temperature and pressure are set according to the actual temperature and pressure conditions of oil and gas reservoirs. The oil, gas, and water samples used in the experiment are all taken from actual oil and gas reservoirs. Design multiple core displacement pressure differentials from low to high as ΔP1, ΔP2, ΔP3, ... ΔP n ; Step 2.3: During the experiment, the temperature, confining pressure, and flowing pressure of the core were raised to the set values ​​using an electric heating jacket, a confining pressure pump, and a displacement pump, respectively. Then, the pressure of the confining pressure pump and the displacement pump were kept constant, and the back pressure was gradually reduced using a back pressure pump to simulate the gradually increasing core displacement pressure difference. The oil and gas flow rate was measured every 5 minutes under each displacement pressure difference. When the difference between three consecutive flow rate measurements was less than 5%, the flow rate under that displacement pressure difference was considered to have reached stability. Step 2.4: Record the steady flow rate of each core under different displacement pressure differentials, where the steady flow rate is the average of the last three measurements.

4. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 3, characterized in that, Step three, establishing the similarity conversion model, includes the following steps: Step 3.1: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the vertical well in the field. Step 3.2: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the oil and gas flow rate at the core outlet and the daily oil and gas production of the vertical well in the field. Step 3.3: Assuming that the oil and gas flow rate at the core outlet under experimental conditions is equal to the oil and gas flow rate at the bottom of the well under field conditions, establish a similar conversion model between the displacement pressure difference of the experimental core and the production pressure difference of the horizontal well in the field. Step 3.4: Define the production index ratio J r For the same gas supply area and production pressure differential, the horizontal well production index J h With vertical well production index J v Based on the ratio, a similarity conversion model is established between the daily oil and gas production of vertical wells and the daily oil and gas production of horizontal wells in the mining area; Step 3.5: For vertical well types, using the vertical well pressure difference similarity conversion formula established in Step 3.1 and the vertical well production similarity conversion formula established in Step 3.2, the displacement pressure difference and oil and gas flow rate data of different physical property cores recorded in Step 2.4 are converted into the production pressure difference and daily oil and gas production of vertical wells in reservoirs with different physical properties. Step 3.6: For horizontal well types, using the horizontal well pressure difference similarity conversion formula established in Step 3.3 and the horizontal well production similarity conversion formula established in Step 3.4, the displacement pressure difference of core samples with different physical properties recorded in Step 2.4 and the daily oil and gas production data of vertical wells obtained in Step 3.5 are respectively converted into the production pressure difference and daily oil and gas production of horizontal wells in reservoirs with different physical properties.

5. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 4, characterized in that, Step four, creating the lower limit chart of the physical properties for benefit development, includes the following steps: Step 4.1: The experimental data points obtained from core samples with different physical properties under different displacement pressure differentials are limited and cannot cover the entire range of physical properties of oil and gas reservoirs and simulate all displacement pressure differentials. Based on the production pressure differential and daily oil and gas production of horizontal wells in reservoirs with different physical properties obtained in Step 3.6, a permeability-pressure differential-production data table is prepared and imported into Surfer software. Step 4.2: In the Surfer software's menu bar, select "Grid," and then select "Data" from the "Grid" drop-down menu. Select permeability for the X-axis data, production pressure differential for the Y-axis data, and daily production capacity for the Z-column data. Set the minimum value for the X-column to 0, and the maximum value for the X-column to K based on the maximum permeability of the core sample. max The minimum value in column Y is set to 0, and the maximum value in column Y is set to ΔP based on the maximum production pressure difference. max The network algorithm selected is "Kriging interpolation" to complete the process of importing basic data and exporting grid files. Step 4.3: In the Surfer software, select "Grid" in the menu bar and "Mathematics" in the drop-down menu. Add the grid file exported in Step 4.2, and select column C corresponding to the production capacity in the Excel data table in "Variable Name". Then enter the formula C = max(C, 0) and export the grid file again. The meaning of this formula is to compare the data in column C with 0, and replace the data in column C with the larger value to eliminate negative numbers. Step 4.4: In the Surfer software, select "Graphics" in the menu bar, and then select "New Contour Map" in the "Graphics" drop-down menu. Then import the grid file obtained in Step 4.

3. Process the obtained contour map, including the scaling of the coordinate axes, the interval of the scale values, the position of the scale values, as well as the contour interval, fill color, transparency, and scale bar of the graph. Step 4.5: In the Surfer software menu bar, select "File", and in the "File" drop-down menu, select "Export". Then, in the save type, select "JPG JPEG Compressed Bitmap", check "Preserve Aspect Ratio" and "Preserve Pixel Density" to export the benefit development property lower limit map drawn in Step 4.4 as a high-definition image. Step 4.6: Surfer software cannot set numbers less than 1 on the coordinate axes, nor can it label the units of the coordinate axes. The coordinate axis units of the lower limit chart of the benefit development properties exported in Step 4.5 need to be edited. Since the production pressure differential of oil and gas wells is generally controlled within 0–100 MPa, the vertical axis unit needs to be set to MPa. The permeability of high-permeability oil and gas reservoirs is generally greater than 1 mD, so the horizontal axis unit needs to be set to mD. The permeability of low-permeability oil and gas reservoirs is partially less than 1 mD, so the horizontal axis unit needs to be set to 10. -1 Or 10 -2 mD; Step 4.7: After setting the units for the horizontal and vertical axes, the lower limit chart of the physical properties for the benefit development of horizontal wells is completed. The lower limit chart of the physical properties for the benefit development of vertical wells can be made by referring to steps 4.1 to 4.6 using the vertical well production pressure difference and daily output data collected in step 3.

5.

6. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 1, characterized in that, Step five, which uses the benefit development property lower limit chart, includes the following steps: Step 5.1: Based on the actual conditions of the mining area and international oil and gas prices, determine the daily production capacity of oil and gas that meets the needs of efficient oil and gas field development. Then, determine the average thickness of the oil and gas reservoir in the study area using geophysical methods, and calculate the daily production capacity per unit reservoir thickness. Step 5.2: Determine the production pressure differential of oil and gas wells according to the oil and gas field development plan of the study area; determine various parameters of oil and gas wells with reference to well type design and construction plan, and select the lower limit chart of the physical properties for the benefit development of corresponding well types and well parameters; Step 5.3: Based on the daily production per unit reservoir thickness of the oil and gas well determined in Step 5.1, find and select the contour line corresponding to its value on the lower limit map of efficient development properties; according to the production pressure difference determined in Step 5.2, find point A on the vertical axis of the lower limit map of efficient development properties, and draw a horizontal line from point A to the selected contour line, intersecting it at point B; draw a perpendicular line from intersection point B to the horizontal axis, intersecting it at point C. The permeability value corresponding to point C is the lower limit permeability value for the oil and gas field to meet the efficient production capacity. Step 5.4: Substitute the lower limit value of permeability obtained in Step 5.3 into the porosity-permeability relationship established in Step 1.3 to calculate the lower limit value of porosity. By changing the efficiency production capacity and reservoir thickness in Step 5.1, and changing the production pressure differential and production well type in Step 5.2, a series of lower limit values ​​of efficient development properties under the influence of multiple factors can be obtained, providing a theoretical basis for calculating the efficient movable reserves of oil and gas fields and formulating drilling and production plans.

7. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 4, characterized in that, In step 3.1, the formula for the gas velocity at the core outlet under the experimental conditions based on Darcy's law is: The formula for the gas velocity at the bottom of a vertical well under mining conditions is: Let p = p in the first formula w1 In the second formula, p = p w2 , r = r w Based on the assumptions, let υ sg =υ vg After simplification, the pressure p at the core outlet can be obtained. w1 Pressure p at the bottom of the vertical well w2 Similarity transformation model between: The experimental displacement pressure differential and the vertical well production pressure differential can be expressed as Δp, respectively. s =p e -p w1 and Δp v =p e -p w2 ; In the formula, K is the reservoir permeability, mD; μ is the gas viscosity, mPa·s; p w1 The pressure at the core outlet is MPa; p w2 The bottom hole pressure of the vertical well is in MPa; p e p is the pressure at the core inlet or the supply pressure at the gas well boundary, in MPa; p is the pressure at any point in the reservoir, in MPa; L is the core length, in m; r e r is the radius of the gas well control area, in meters (m). w denoted as , where is the radius of the gas wellbore, in meters; denoted as r, where r is the distance from any point in the reservoir to the bottom of the well, in meters. In step 3.2, the formula for the gas velocity at the core outlet in the experiment is: The formula for the gas velocity at the bottom of the well under mining conditions is: Based on the assumptions, let υ sg =υ rg After simplification, the oil and gas flow rate Q at the core outlet can be obtained. R Daily gas production Q of vertical well vg Similarity transformation model between: In the formula Q vg For the daily gas production of a vertical well, 10 4 m 3 / d;Q R The gas flow rate at the core outlet is m. 3 / s;r w denoted as , where is the wellbore radius (m); h is the reservoir thickness (m); and D is the core diameter (m).

8. The method for producing a lower limit chart of physical properties for efficient development of oil and gas reservoirs according to claim 7, characterized in that, In step 3.3, the gas velocity formula at the core outlet is based on Darcy's law. And the improved Joshi horizontal well bottom hole gas velocity formula The obtained core outlet pressure p w1 Pressure p at the bottom of the horizontal well w3 The similarity transformation model between them is: The experimental displacement pressure differential and the vertical well production pressure differential can be expressed as Δp, respectively. s =p e -p w1 and Δp v =p e -p w3 ; In the formula, p w3 For horizontal well bottom hole pressure, MPa; L h The length of the horizontal section of the horizontal well is in meters (m). r wh Where is the radius of the horizontal wellbore, in meters; and T is the reservoir temperature, in kilometer markers (K). Here, is the gas deviation factor; 'a' is the major axis of the horizontal well ellipse, expressed as: In the formula r eh Let be the control radius of the horizontal well, in meters (m).

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