Method and device for digital measurement of oil well under gas effect

Abstract

The application discloses a method and device for oil well digital metering under gas influence conditions, and the method comprises the following steps: determining the free gas molar quantity in each pumping unit corresponding to a pumping diagram; determining the liquid production of each pumping unit corresponding to the pumping diagram according to the free gas molar quantity in each pumping unit corresponding to the pumping diagram and a previously established pumping unit liquid production model; the pumping unit liquid production model is a pumping unit liquid production model previously established by considering the influence of gas on the liquid production; and accumulating the wellhead liquid production corresponding to each pumping diagram to obtain the accumulated wellhead liquid production of the pumping unit. The application quantitatively considers the degree of gas influence, corrects the liquid production of the pumping unit under the gas influence condition, and improves the accuracy of the pumping diagram liquid production.

Description

Technical Field

[0001] This invention relates to the field of digital metering technology in oilfield mechanical oil production, and in particular to a method and apparatus for digital metering of oil wells under gas-affected conditions. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] China has a large number of oil wells spread across a wide area, and in recent years, the quality of resources has deteriorated, operating conditions have become increasingly complex, and production has declined year by year. Platform cluster wells have increased significantly, with each platform typically containing 4-8 wells. Oil well metering is dominated by traditional metering stations, currently numbering in the tens of thousands. Each station occupies over 100 square meters and requires hundreds to several kilometers of metering pipelines, resulting in huge investments. Each metering station requires 2-3 personnel for daily operation and maintenance. Metering cycles are long and significantly delayed, making it difficult to track well production dynamics in a timely manner. For manually operated metering stations, metering is only performed on average every 10 days per well, with each measurement typically taking four hours, resulting in high labor intensity.

[0004] The lifting of an oil pumping unit relies on the pumping unit driving the sucker rod, which in turn drives the plunger pump in a continuous reciprocating motion to extract oil. Each pumping operation generates a dynamometer chart (DDT). The DDT is a closed curve composed of load and displacement, containing information such as well conditions, production, and fluid level—crucial first-hand data for oil well production. After years of continuous exploration, digital metering technology for pumping unit wells has developed rapidly, but currently it only focuses on DDT for oil or fluid production. Methods for DDT for oil production include the line method, area method, and decomposition method, with the decomposition method currently being the mainstream approach. Currently, the accuracy of determining fluid production using DDT is low. Summary of the Invention

[0005] This invention provides a method for digital metering of oil wells under gas-affected conditions, used to quantitatively consider the degree of gas influence, correct the production rate of pumping wells under gas-affected conditions, and improve the accuracy of production rate calculation using dynamometer cards. The method includes:

[0006] Determine the molar amount of free gas in the oil pump corresponding to each pumping indicator diagram;

[0007] Based on the molar amount of free gas in the pump corresponding to each pumping indicator diagram and the pre-established pumping well production rate model, the production rate of the pumping well corresponding to each pumping indicator diagram is determined; the production rate model of the pumping well is a pre-established production rate model of the pumping well that takes into account the influence of gas on the production rate.

[0008] The cumulative fluid production at the wellhead corresponding to each pumping indicator diagram is accumulated to obtain the cumulative fluid production at the pumping unit wellhead.

[0009] In one embodiment, the above-mentioned method for digital metering of oil wells under gas-affected conditions further includes pre-establishing a production volume model for pumping unit wells according to the following method:

[0010] Force analysis was performed on the plunger of the oil pump to obtain the internal pressure model of the pump during the preset process segment of the downstroke.

[0011] Based on the pump load model when the traveling valve opens after the downstroke load is unloaded, the pump outlet pressure model is obtained.

[0012] Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, the pump internal pressure model when the traveling valve is open is obtained.

[0013] Based on the gas state equation, the pump pressure model at different displacements of the plunger during the downstroke load unloading process is obtained.

[0014] Based on the pump pressure model when the traveling valve is open, and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, a model for solving the molar amount of free gas at the pump is obtained.

[0015] Based on the model for solving the molar amount of free gas at the pump, the model for calculating the production volume of the pumping unit well is obtained.

[0016] In one embodiment, the pump pressure during the preset downstroke phase is the pump pressure obtained by ignoring the weight of the plunger itself and the friction between the plunger and the working cylinder wall.

[0017] In one embodiment, the pump outlet pressure is the pump outlet pressure obtained by ignoring the resistance of the fluid passing through the traveling valve.

[0018] In one embodiment, determining the molar amount of free gas in the pump corresponding to each pumping indicator diagram includes:

[0019] Take multiple data points on the preset process segment curve of the downstroke on each pump dynamometer diagram;

[0020] Based on each data point and the pre-established model for solving the molar amount of free gas at the pump, a set of equations for solving the molar amount of free gas at the pump is constructed.

[0021] Solving the system of equations yields the molar amount of free gas in the oil pump corresponding to each pumping indicator diagram.

[0022] In one embodiment, the model for solving the molar amount of free gas at the pump is:

[0023]

[0024] Among them, F pdPump load when the traveling valve is open; A p A is the cross-sectional area of ​​the plunger; r The cross-sectional area of ​​the tie rod connected to the pump; n is the number of moles of gas; Z is the compressibility factor; R is the gas constant; T is the pump internal temperature; s l The effective liquid production stroke is given by F; u is the displacement of any point during unloading. d This represents the piston load during the downstroke.

[0025] In one embodiment, the above-mentioned method for digital metering of oil wells under gas-affected conditions further includes: solving the set of equations to obtain the effective production stroke corresponding to each pumping indicator diagram;

[0026] Based on the molar amount of free gas in the pump corresponding to each dynamometer card and the pre-established pumping unit well production rate model, the production rate of the pumping unit well corresponding to each dynamometer card is determined, including:

[0027] Based on the molar amount of free gas in the pump corresponding to each dynamometer diagram, the effective production stroke corresponding to each dynamometer diagram, and the pre-established production model of the pumping unit well, the production of the pumping unit well corresponding to each dynamometer diagram is determined.

[0028] In one embodiment, solving the system of equations to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram includes: when the number of data points is greater than 3, solving the system of equations using the least squares method to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram.

[0029] In one embodiment, the production volume model for the pumping unit well is as follows:

[0030] Q l =1440η l η B A p S l n;

[0031] Among them, Q l η represents the fluid production of the pumping unit well. l η is the leakage coefficient representing the impact of pump leakage on pump efficiency. B A is the volume factor of degassed crude oil at the surface. p S is the cross-sectional area of ​​the plunger. l The effective liquid production stroke is defined as n, where n is the molar amount of free gas.

[0032] This invention also provides a device for digital metering of oil wells under gas-affected conditions, used to quantitatively consider the degree of gas influence, correct the production rate of pumping wells under gas-affected conditions, and improve the accuracy of production rate calculation using dynamometer cards. The device includes:

[0033] The gas molar quantity determination unit is used to determine the molar quantity of free gas in the oil pump corresponding to each pumping indicator diagram.

[0034] The prediction unit is used to determine the production volume of the pumping unit well corresponding to each pumping indicator diagram based on the molar amount of free gas in the pumping unit corresponding to each pumping indicator diagram and the pre-established production volume model of the pumping unit well; the production volume model of the pumping unit well is a pre-established production volume model of the pumping unit well that takes into account the influence of gas on the production volume.

[0035] The final production volume determination unit is used to accumulate the wellhead production volume corresponding to each pumping indicator to obtain the cumulative production volume of the pumping unit wellhead.

[0036] In one embodiment, the device for digital metering of oil wells under gas-affected conditions further includes: a modeling unit for pre-establishing a production volume model for a pumping unit well according to the following method:

[0037] Force analysis was performed on the plunger of the oil pump to obtain the internal pressure model of the pump during the preset process segment of the downstroke.

[0038] Based on the pump load model when the traveling valve opens after the downstroke load is unloaded, the pump outlet pressure model is obtained.

[0039] Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, the pump internal pressure model when the traveling valve is open is obtained.

[0040] Based on the gas state equation, the pump pressure model at different displacements of the plunger during the downstroke load unloading process is obtained.

[0041] Based on the pump pressure model when the traveling valve is open, and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, a model for solving the molar amount of free gas at the pump is obtained.

[0042] Based on the model for solving the molar amount of free gas at the pump, the model for calculating the production volume of the pumping unit well is obtained.

[0043] In one embodiment, the pump pressure during the preset downstroke phase can be the pump pressure obtained by ignoring the weight of the plunger itself and the friction between the plunger and the working cylinder wall.

[0044] In one embodiment, the pump outlet pressure can be the pump outlet pressure obtained by ignoring the resistance of the fluid passing through the traveling valve.

[0045] In one embodiment, the gas molar quantity determination unit is specifically used for:

[0046] Take multiple data points on the preset process segment curve of the downstroke on each pump dynamometer diagram;

[0047] Based on each data point and the pre-established model for solving the molar amount of free gas at the pump, a set of equations for solving the molar amount of free gas at the pump is constructed.

[0048] Solving the system of equations yields the molar amount of free gas in the oil pump corresponding to each pumping indicator diagram.

[0049] In one embodiment, the model for solving the molar amount of free gas at the pump can be:

[0050]

[0051] Among them, F TV Pump load when the traveling valve is open; A p A is the cross-sectional area of ​​the plunger; r The cross-sectional area of ​​the tie rod connected to the pump; n is the number of moles of gas; Z is the compressibility factor; R is the gas constant; T is the pump internal temperature; s l The effective liquid production stroke is given by F; u is the displacement of any point during unloading. d This represents the piston load during the downstroke.

[0052] In one embodiment, the gas molar quantity determination unit can also be used to: solve the equation set to obtain the effective liquid production stroke corresponding to each pumping diagram;

[0053] Based on the molar amount of free gas in the pump corresponding to each dynamometer card and the pre-established pumping unit well production rate model, the production rate of the pumping unit well corresponding to each dynamometer card is determined, including:

[0054] Based on the molar amount of free gas in the pump corresponding to each dynamometer diagram, the effective production stroke corresponding to each dynamometer diagram, and the pre-established production model of the pumping unit well, the production of the pumping unit well corresponding to each dynamometer diagram is determined.

[0055] In one embodiment, solving the system of equations to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram may include: when the number of data points is greater than 3, solving the system of equations using the least squares method to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram.

[0056] In one embodiment, the production rate model for the pumping unit well can be:

[0057] Q l =1440η l η B A p S l n;

[0058] Among them, Q lη represents the fluid production of the pumping unit well. l η is the leakage coefficient representing the impact of pump leakage on pump efficiency. B A is the volume factor of degassed crude oil at the surface. p S is the cross-sectional area of ​​the plunger. l The effective liquid production stroke is defined as n, where n is the molar amount of free gas.

[0059] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described method for digital metering of oil wells under gas-affected conditions.

[0060] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for digital metering of oil wells under gas-affected conditions.

[0061] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-mentioned method for digital metering of oil wells under gas-affected conditions.

[0062] In this embodiment of the invention, the scheme for digital metering of oil wells under gas-affected conditions involves: determining the molar amount of free gas in the pump corresponding to each dynamometer card; determining the production volume of the pumping unit well corresponding to each dynamometer card based on the molar amount of free gas in the pump corresponding to each dynamometer card and a pre-established production volume model for the pumping unit well; wherein the production volume model for the pumping unit well is a pre-established production volume model for the pumping unit well that considers the influence of gas on the production volume; and accumulating the wellhead production volume corresponding to each dynamometer card to obtain the cumulative production volume at the pumping unit wellhead. This scheme quantitatively considers the degree of gas influence, corrects the production volume of the pumping unit well under gas-affected conditions, and improves the accuracy of production volume determined by dynamometer cards. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0064] Figure 1 This is a flowchart illustrating the method for digital metering of oil wells under gas-affected conditions in an embodiment of the present invention.

[0065] Figure 2 This is a schematic diagram of the effective liquid production stroke considering the influence of gas in an embodiment of the present invention;

[0066] Figure 3 This is a schematic diagram illustrating the pre-established production model for a pumping well in an embodiment of the present invention.

[0067] Figure 4 This is a schematic diagram illustrating the determination of the molar amount of free gas inside the oil pump corresponding to each pumping indicator diagram in an embodiment of the present invention.

[0068] Figure 5 This is a schematic diagram of the structure of the digital metering device for oil wells under gas-affected conditions in an embodiment of the present invention;

[0069] Figure 6 This is a schematic diagram of the structure of a computer device in an embodiment of the present invention. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0071] In this document, the term "and / or" merely describes a relationship, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0072] In the description of this specification, the terms "comprising," "including," "having," and "containing" are open-ended terms, meaning that they include but are not limited to. The terms "an embodiment," "a specific embodiment," "some embodiments," and "for example," etc., refer to specific features, structures, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of this application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0073] The inventors discovered a technical problem: gas affects pump dynamometer cards. For dynamometer cards affected by gas, the accuracy of calculating production volume from the dynamometer card has always been low because the amount of gas inside the pump cannot be quantitatively calculated. Having identified this problem, the inventors proposed a method for digital metering of oil wells under gas-affected conditions. This method quantitatively considers the degree of gas influence, corrects for the production volume of pumping units under gas-affected conditions, improves the accuracy of production volume calculation from the dynamometer card, and achieves higher-precision digital oil metering. This facilitates the elimination of metering rooms, reduces frontline labor, and transforms traditional production management methods. The following is a detailed introduction to this method for digital metering of oil wells under gas-affected conditions.

[0074] Figure 1 This is a flowchart illustrating the method for digital metering of oil wells under gas-affected conditions in an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0075] Step 101: Determine the molar amount of free gas in the pump corresponding to each pumping indicator diagram;

[0076] Step 102: Determine the production volume of the pumping unit well corresponding to each pumping indicator diagram based on the molar amount of free gas in the pumping pump corresponding to each pumping indicator diagram and the pre-established production volume model of the pumping unit well; the production volume model of the pumping unit well is a pre-established production volume model of the pumping unit well that takes into account the influence of gas on the production volume.

[0077] Step 103: Accumulate the wellhead fluid production corresponding to each pumping indicator diagram to obtain the cumulative wellhead fluid production of the pumping unit. The obtained cumulative wellhead fluid production of the pumping unit is used to guide the development and production of oil and gas.

[0078] The method for digital metering of oil wells under gas-affected conditions provided in this invention involves the following steps: determining the molar amount of free gas in the pump corresponding to each dynamometer card; determining the production volume of the pumping unit well corresponding to each dynamometer card based on the molar amount of free gas in the pump corresponding to each dynamometer card and a pre-established production volume model for the pumping unit well; the production volume model for the pumping unit well is a pre-established model that considers the influence of gas on the production volume; and accumulating the wellhead production volume corresponding to each dynamometer card to obtain the cumulative production volume at the pumping unit wellhead. This method quantitatively considers the degree of gas influence, corrects the production volume of the pumping unit well under gas-affected conditions, and improves the accuracy of production volume calculation based on dynamometer cards. The method for digital metering of oil wells under gas-affected conditions will be described in detail below.

[0079] First, the steps for determining the production volume model of a pumping unit well are introduced.

[0080] 1) Calculate the pump pressure during the downstroke.

[0081] If the given dynamometer card is a surface dynamometer card, it needs to be converted into a downhole pump dynamometer card according to the wave equation. For pump dynamometer cards affected by gas, the gas effect is mainly reflected in the unloading process of the pump downstroke load. Taking the oil pump plunger as the research object, a force analysis is performed on it, while neglecting the plunger's own weight W. p The frictional force f between the plunger and the working cylinder wall, and the pump pressure during the downstroke from C to D are:

[0082]

[0083] Among them, F d p0 is the piston load during the downstroke, in N; p0 is the pressure at the pump outlet, in Pa; pp p The pressure inside the pump during the downstroke stroke is Pa; A p Let m be the cross-sectional area of ​​the plunger. 2 A r m is the cross-sectional area of ​​the tie rod connected to the pump. 2 .

[0084] As can be seen from the above, in one embodiment, the pump pressure during the preset downstroke process is the pump pressure obtained by ignoring the weight of the plunger itself and the friction between the plunger and the working cylinder wall.

[0085] 2) Pump outlet pressure

[0086] The pump outlet pressure can be obtained by, but is not limited to, the following methods: 1) measuring the pump outlet pressure with a sensor; 2) calculating the pump outlet pressure from the wellhead downwards using multiphase flow theory; 3) the following simplified calculation method is given in the embodiments of the present invention.

[0087] After the current stroke unloading is completed, the upper traveling valve of the pump opens. At this time, the pressure inside the pump is equal to the sum of the pump outlet pressure and the pressure drop of the fluid through the traveling valve, which is:

[0088] F TV =p0A p -f p (2)

[0089] Among them, F TV Pump load when the traveling valve is open, N; f p The resistance of the fluid passing through the traveling valve is expressed in Pa.

[0090] During the unloading process, since the plunger's downward distance is limited and the wellhead pressure changes little, it is assumed that the pump outlet pressure remains constant during this process. Furthermore, the resistance of the fluid passing through the traveling valve is ignored. The pump outlet pressure can be calculated using equation (2) as follows:

[0091] p0 = F TV / A p (3)

[0092] Substituting equation (3) into equation (1), we obtain the pump pressure as follows:

[0093]

[0094] As can be seen from the above, in one embodiment, the pump outlet pressure is the pump outlet pressure obtained by ignoring the resistance of the fluid passing through the traveling valve.

[0095] 3) Gas Law

[0096] Meanwhile, during the unloading process of the downstroke pump, the pump pressure at different locations can be obtained according to the gas state equation:

[0097]

[0098] Where n is the number of moles of gas (mol); Z is the compressibility factor, which can be obtained by looking up a table or using an empirical formula; and R is the gas constant, R = 8.3145 Pa·m. 3 / (mol·K); T is the pump internal temperature, K; u D Let be the displacement of the plunger when the traveling valve opens, m; u be the displacement of any point during unloading, m; s q Let u be the height of the air column inside the pump when the traveling valve is open, in meters (m). Specifically, when the plunger is at top dead center, u = u0. C , where u C The displacement of the top dead center piston is m; when the traveling valve is open, u = u D .

[0099] 4) Solve for the molar amount of free gas at the pump and the effective liquid production during the stroke.

[0100] During the unloading process, both the moving valve and the stationary valve are closed. As the plunger descends, the gas is continuously compressed, but the number of moles of gas remains constant. Combining Equations 4 and 5, we can obtain the following Equation (6). In one embodiment, the model for solving the molar amount of free gas at the pump can be:

[0101]

[0102] Among them, s l The effective liquid production stroke is defined as u, where u is the displacement of any point during the unloading process.

[0103] The above equation (formula (6)) has three unknowns s. l , n, T, such as Figure 2 As shown, if k points (k ≥ 3) are randomly selected on the C to D curve of the pump power diagram, the following system of equations is formed:

[0104]

[0105] Among them, F d1 Pump load (N; F) from dead point C on the pump power diagram to point 1 inside the floating valve opening point D. d2 Pump load (N; F) from dead point C on the pump power diagram to point 2 inside the floating valve opening point D. dk The pump load at different plunger displacements during unloading, for example, the pump pressure at point k inside the traveler valve opening point D on the pump power diagram, in N; the subscript k represents any selected point on the pump power diagram from the bottom dead center C to the traveler valve opening point D. For ease of representation and calculation, points are selected sequentially from C to D, i = 1, 2, 3, ..., k, that is, the pump load i = 1 is closer to the wellhead, and so on downwards, i = m is closer to the bottom of the well, in N; the subscript k represents any selected point on the pump power diagram from the bottom dead center C to the traveler valve opening point D. For ease of representation and calculation, points are selected sequentially from C to D, i = 1, 2, 3, ..., k, ..., that is, i = 1 is closer to the wellhead, and so on downwards, i = k is closer to the bottom of the well; Z1 is the pump gas compressibility factor at point 1 inside the traveler valve opening point D on the pump power diagram; Z2 is the pump gas compressibility factor at point m inside the traveler valve opening point D on the pump power diagram; Z k The pump gas compressibility factor at different plunger displacements during unloading, for example, the pump gas compressibility factor from dead center C on the pump dynamometer card to point k inside the moving valve opening point D; u1 is the displacement from dead center C on the pump dynamometer card to point 1 inside the moving valve opening point D, in meters; u2 is the displacement from dead center C on the pump dynamometer card to point 2 inside the moving valve opening point D, in meters; u k The value m represents the different displacements of the plunger during the unloading process, such as the different displacements from the dead point C on the pump power diagram to the inner point k of the floating valve opening point D.

[0106] Solving the equations yields the effective liquid production stroke, the molar amount of free gas, and the temperature at the pump. To improve the accuracy of the numerical calculations, when the number of points k is greater than 3, the least squares method can be used to calculate the above set of equations.

[0107] 5) Determine the wellhead fluid production rate

[0108] The production rate, taking into account the influence of gas, is calculated using a decomposition method. Specifically, in one embodiment, the production rate calculation model for the pumping unit well can be:

[0109] Q l =1440η l η B A p S l n (8)

[0110] Among them, Q l η represents the fluid production of the pumping unit well. l η is the leakage coefficient representing the impact of pump leakage on pump efficiency. BA is the volume factor of degassed crude oil at the surface. p S is the cross-sectional area of ​​the plunger. l The effective liquid production stroke is defined as n, where n is the molar amount of free gas.

[0111] As can be seen from the above, in one embodiment, such as Figure 3 As shown, the above-mentioned method for digital metering of oil wells under gas-affected conditions can also include pre-establishing a production volume model for pumping unit wells according to the following method:

[0112] Step 201: Perform a force analysis on the plunger of the oil pump to obtain the pump internal pressure model for the preset process segment of the downstroke (which can be the above formula (1));

[0113] Step 202: Based on the pump load model when the traveling valve opens after the downstroke load is unloaded (which can be the above formula (2)), obtain the pump outlet pressure model (which can be the above formula (3));

[0114] Step 203: Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, obtain the pump internal pressure model when the traveling valve is open (which can be the above formula (4));

[0115] Step 204: Obtain the pump pressure model at different displacements of the plunger during the downstroke load unloading process based on the gas state equation (which can be the above formula (5));

[0116] Step 205: Based on the pump pressure model when the traveling valve is open and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, obtain the model for solving the molar amount of free gas at the pump (which can be the above formula (6));

[0117] Step 206: Based on the model for solving the molar amount of free gas at the pump, obtain the model for calculating the production volume of the pumping well (which can be the above formula (8)).

[0118] Secondly, the steps for digital metering of oil wells under gas-affected conditions are introduced using the established pumping unit well production volume model.

[0119] In step 101 above, in one embodiment, such as Figure 4 As shown, determining the molar amount of free gas in the pump corresponding to each pumping indicator diagram can include:

[0120] Step 1011: Randomly select multiple data points (k points) on the preset process segment curve of the downstroke on each pump dynamometer card;

[0121] Step 1012: Based on each data point and the pre-established model for solving the molar amount of free gas at the pump, construct a set of equations for solving the molar amount of free gas at the pump (which can be the above formula (7));

[0122] Step 1013: Solve the set of equations to obtain the molar amount of free gas in the oil pump corresponding to each pumping indicator diagram.

[0123] In practice, the above-mentioned method of determining the molar amount of free gas in the pump corresponding to each pumping indicator diagram further improves the accuracy of digital metering of oil wells under gas-affected conditions.

[0124] As can be seen from the above, in one embodiment, solving the equation set to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram can include: when the number of data points is greater than 3, using the least squares method to solve the equation set to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram, thereby improving the accuracy of obtaining the molar amount of free gas, and further improving the accuracy of digital metering of oil wells under gas-affected conditions.

[0125] For a detailed description of the implementation of step 101 above, please refer to the section “4) Solving for the molar amount of free gas at the pump and the effective liquid production stroke” above.

[0126] For a detailed description of the implementation of step 102 above, please refer to the section “5) Solving for the wellhead fluid production” above.

[0127] In step 103 above, the real-time production volume of the pumping unit well can be obtained at any time period according to the user's actual needs, such as measuring the production volume of the pumping unit well in real time for 24 hours.

[0128] In a further preferred embodiment, the above-mentioned method for digital metering of oil wells under gas-affected conditions may further include:

[0129] Based on the wellhead production rate corresponding to each pumping indicator diagram of the pumping unit, the change curve of the pumping unit well production rate is obtained.

[0130] The production dynamics of the pumping well are analyzed based on the change curve of the pumping well's fluid production.

[0131] In practical implementation, the embodiments of the present invention can not only accurately calculate the cumulative fluid production of oil wells every day or within a specified time period, but also dynamically analyze the changing patterns of oil well production, analyze the production dynamics of oil wells, and guide the development and production of oil and gas.

[0132] This invention takes a well in the Changqing Oilfield as an example. The basic data of this well are as follows: wellhead pressure 0.2 MPa, wellhead temperature 40℃, plunger pump diameter 32 mm, stroke 1.5 m, sucker rod diameter 19 mm, pump depth 850 m, and dissolved gas-liquid ratio at the pump 5 m. 3 / m 3 At the same time, a measured surface dynamometer is required, and the downhole pump dynamometer is solved by applying the three-dimensional wave equation to the surface dynamometer.

[0133] For the downhole pump dynamometer, two sets of data points are arbitrarily selected during the load unloading process (C→D) to obtain the corresponding load and displacement. To improve the accuracy of the calculation, K data points (K greater than 3) are selected between points C and D on the pump dynamometer according to the method in Section 4. The effective production stroke of the pump is solved using equation (7), and the production rate considering the gas effect is calculated using equation (8). The figure below shows the dynamometer at different time points within a certain period of the well, as well as the production rate curve at the wellhead calculated by the above method.

[0134] In addition, the method for digital metering of oil wells under gas-affected conditions proposed in this embodiment of the invention is more applicable to pumping wells where the gas-liquid ratio is greater than the dissolved gas-liquid ratio at the pump. The dynamometer card should have certain gas-affected graphic characteristics (preset gas-affected graphic characteristics), and generally the gas production is large (gas production is greater than the preset value).

[0135] The main features of the digital metering method for oil wells under gas-affected conditions proposed in this invention are as follows:

[0136] 1) A low-cost method for determining digital metering of oil wells under gas-affected conditions is proposed.

[0137] 2) This method is based on the dynamometer diagram of the pumping unit well. The dynamometer diagram can be a measured surface dynamometer diagram or a dynamometer diagram converted from electrical parameters.

[0138] 3) This method is based on the characteristics of the work diagram and the gas law.

[0139] 4) The calculation process of the molar amount of free gas inside the oil pump is given.

[0140] 5) This method corrects the calculation method of pumping well production under gas influence conditions and improves the accuracy of production calculation by dynamometer card.

[0141] 6) An edge computing device with the above method (the method of digital metering of oil wells under gas-affected conditions) has been formed. It can be installed at the oil well site to calculate the production volume corresponding to each pumping indicator in real time, thereby calculating the cumulative production volume at the pumping unit wellhead.

[0142] In summary, the advantages of this invention are: This invention proposes a method for digital metering of oil wells under gas-affected conditions. For dynamometer cards affected by gas, it quantitatively considers the degree of gas influence, improving the accuracy of production calculation from the dynamometer card. The results of this invention facilitate the elimination of metering rooms, reduces frontline labor, transforms traditional production management methods, and truly transforms oilfield workers from blue-collar to white-collar workers. Based on this invention, 24-hour real-time measurement of pumping unit well production can be achieved. It can not only accurately calculate the cumulative production of oil wells daily or over a specified time period, but also dynamically analyze the changing patterns of oil well production, enabling analysis of the oil well's production dynamics.

[0143] This invention also provides a device for digital metering of oil wells under gas-affected conditions, as described in the following embodiments. Since the principle behind this device is similar to the method for digital metering of oil wells under gas-affected conditions, its implementation can refer to the implementation of a method for digital metering of oil wells under gas-affected conditions; therefore, repeated details will not be elaborated further.

[0144] Figure 5 This is a schematic diagram of the structure of the digital metering device for oil wells under gas-affected conditions in an embodiment of the present invention, as shown below. Figure 5 As shown, the device includes:

[0145] Gas molar quantity determination unit 01 is used to determine the molar quantity of free gas in the oil pump corresponding to each pumping indicator diagram.

[0146] Prediction unit 02 is used to determine the production volume of the pumping unit well corresponding to each pumping indicator diagram based on the molar amount of free gas in the pumping unit corresponding to each pumping indicator diagram and the pre-established production volume model of the pumping unit well; the production volume model of the pumping unit well is a pre-established production volume model of the pumping unit well that takes into account the influence of gas on the production volume.

[0147] The final production volume determination unit 03 is used to accumulate the wellhead production volume corresponding to each pumping indicator to obtain the cumulative production volume of the pumping unit wellhead.

[0148] In one embodiment, the device for digital metering of oil wells under gas-affected conditions may further include: a modeling unit for pre-establishing a production volume model for a pumping unit well according to the following method:

[0149] Force analysis was performed on the plunger of the oil pump to obtain the internal pressure model of the pump during the preset process segment of the downstroke.

[0150] Based on the pump load model when the traveling valve opens after the downstroke load is unloaded, the pump outlet pressure model is obtained.

[0151] Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, the pump internal pressure model when the traveling valve is open is obtained.

[0152] Based on the gas state equation, the pump pressure model at different displacements of the plunger during the downstroke load unloading process is obtained.

[0153] Based on the pump pressure model when the traveling valve is open, and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, a model for solving the molar amount of free gas at the pump is obtained.

[0154] Based on the model for solving the molar amount of free gas at the pump, the model for calculating the production volume of the pumping unit well is obtained.

[0155] In one embodiment, the pump pressure during the preset downstroke phase can be the pump pressure obtained by ignoring the weight of the plunger itself and the friction between the plunger and the working cylinder wall.

[0156] In one embodiment, the pump outlet pressure can be the pump outlet pressure obtained by ignoring the resistance of the fluid passing through the traveling valve.

[0157] In one embodiment, the gas molar quantity determination unit is specifically used for:

[0158] Take multiple data points on the preset process segment curve of the downstroke on each pump dynamometer diagram;

[0159] Based on each data point and the pre-established model for solving the molar amount of free gas at the pump, a set of equations for solving the molar amount of free gas at the pump is constructed.

[0160] Solving the system of equations yields the molar amount of free gas in the oil pump corresponding to each pumping indicator diagram.

[0161] In one embodiment, the model for solving the molar amount of free gas at the pump can be:

[0162]

[0163] Among them, F TV Pump load when the traveling valve is open; A p A is the cross-sectional area of ​​the plunger; r The cross-sectional area of ​​the tie rod connected to the pump; n is the number of moles of gas; Z is the compressibility factor; R is the gas constant; T is the pump internal temperature; s l The effective liquid production stroke is given by F; u is the displacement of any point during unloading. d This represents the piston load during the downstroke.

[0164] In one embodiment, the gas molar quantity determination unit can also be used to: solve the equation set to obtain the effective liquid production stroke corresponding to each pumping diagram;

[0165] Based on the molar amount of free gas in the pump corresponding to each dynamometer card and the pre-established pumping unit well production rate model, the production rate of the pumping unit well corresponding to each dynamometer card is determined, including:

[0166] Based on the molar amount of free gas in the pump corresponding to each dynamometer diagram, the effective production stroke corresponding to each dynamometer diagram, and the pre-established production model of the pumping unit well, the production of the pumping unit well corresponding to each dynamometer diagram is determined.

[0167] In one embodiment, solving the system of equations to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram may include: when the number of data points is greater than 3, solving the system of equations using the least squares method to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram.

[0168] In one embodiment, the production rate model for the pumping unit well can be:

[0169] Q l =1440η l η B A p S l n;

[0170] Among them, Q l η represents the fluid production of the pumping unit well. l η is the leakage coefficient representing the impact of pump leakage on pump efficiency. B A is the volume factor of degassed crude oil at the surface. p S is the cross-sectional area of ​​the plunger. l The effective liquid production stroke is defined as n, where n is the molar amount of free gas.

[0171] In a further preferred embodiment, the above-mentioned device for digital metering of oil wells under gas-affected conditions may further include:

[0172] The change determination unit is used to obtain the change curve of the pumping unit well production based on the wellhead production corresponding to each pumping indicator diagram of the pumping unit.

[0173] The dynamic analysis unit is used to analyze the production dynamics of the pumping well based on the change curve of the pumping well's fluid production.

[0174] Based on the aforementioned inventive concept, such as Figure 6 As shown, the present invention also proposes a computer device 500, including a memory 510, a processor 520, and a computer program 530 stored in the memory 510 and executable on the processor 520. When the processor 520 executes the computer program 530, it realizes the aforementioned method for digital metering of oil wells under gas-affected conditions.

[0175] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for digital metering of oil wells under gas-affected conditions.

[0176] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-mentioned method for digital metering of oil wells under gas-affected conditions.

[0177] In this embodiment of the invention, the scheme for digital metering of oil wells under gas-affected conditions involves: determining the molar amount of free gas in the pump corresponding to each dynamometer card; determining the production volume of the pumping unit well corresponding to each dynamometer card based on the molar amount of free gas in the pump corresponding to each dynamometer card and a pre-established production volume model for the pumping unit well; wherein the production volume model for the pumping unit well is a pre-established production volume model for the pumping unit well that considers the influence of gas on the production volume; and accumulating the wellhead production volume corresponding to each dynamometer card to obtain the cumulative production volume at the pumping unit wellhead. This scheme quantitatively considers the degree of gas influence, corrects the production volume of the pumping unit well under gas-affected conditions, and improves the accuracy of production volume determined by dynamometer cards.

[0178] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0179] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0180] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0181] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0182] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for digital metering of oil wells in gas effecting conditions, characterized in that, include: The method comprises the following steps: selecting multiple data points on a preset process curve of a lower stroke of each pumping diagram; constructing an equation group for solving the free gas molar quantity at the pump according to each data point and a model for solving the free gas molar quantity at the pump; and solving the equation group to obtain the free gas molar quantity in the oil pump corresponding to each pumping diagram. ; wherein, is the pump load when the traveling valve is opened; is the cross-sectional area of the plunger; is the cross-sectional area of the pull rod connected to the pump; n is the molar quantity of the gas; Z is the compression factor; R is the gas constant; and T is the temperature in the pump; is the effective liquid production stroke; u is the displacement of an arbitrary point in the unloading process; F d is the plunger load when the lower stroke is performed. According to the free gas molar quantity in the oil pump corresponding to each pumping diagram, and a pre-established pumping unit liquid production model, the liquid production of the pumping unit corresponding to each pumping diagram is determined; the pumping unit liquid production model is a pumping unit liquid production model pre-established by considering the influence of gas on the liquid production; the pumping unit liquid production model is: ; wherein, is the liquid production of the pumping unit, is a leakage coefficient of the influence of pump leakage on pump efficiency, is a volume coefficient of the degassed crude oil on the ground, is a cross-sectional area of the plunger, is an effective liquid production stroke, is a free gas molar quantity; The cumulative wellhead fluid production corresponding to each pumping indicator diagram is accumulated to obtain the cumulative wellhead fluid production of the pumping unit.

2. The method for digital metering of oil wells in gas effecting operating conditions according to claim 1, characterized in that, This also includes pre-establishing a production model for pumping wells using the following method: Force analysis was performed on the plunger of the oil pump to obtain the internal pressure model of the pump during the preset process segment of the downstroke. Based on the pump load model when the traveling valve opens after the downstroke load is unloaded, the pump outlet pressure model is obtained. Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, the pump internal pressure model when the traveling valve is open is obtained. Based on the gas state equation, the pump pressure model at different displacements of the plunger during the downstroke load unloading process is obtained. Based on the pump pressure model when the traveling valve is open, and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, a model for solving the molar amount of free gas at the pump is obtained. Based on the model for solving the molar amount of free gas at the pump, the model for calculating the production volume of the pumping unit well is obtained.

3. The method for digital metering of oil wells in gas effecting operating conditions according to claim 2, characterized in that, The pump pressure during the preset downstroke process is the pump pressure obtained by ignoring the weight of the plunger itself and the friction between the plunger and the working cylinder wall.

4. The method for digital metering of oil wells in gas effecting operating conditions according to claim 2, characterized in that, The pump outlet pressure is the pump outlet pressure obtained by ignoring the resistance of the fluid passing through the traveling valve.

5. The method for digital metering of oil wells in gas effecting operating conditions according to claim 1, characterized in that, It also includes: solving the system of equations to obtain the effective liquid production stroke corresponding to each pumping indicator diagram; Based on the molar amount of free gas in the pump corresponding to each dynamometer card and the pre-established pumping unit well production rate model, the production rate of the pumping unit well corresponding to each dynamometer card is determined, including: Based on the molar amount of free gas in the pump corresponding to each dynamometer diagram, the effective production stroke corresponding to each dynamometer diagram, and the pre-established production model of the pumping unit well, the production of the pumping unit well corresponding to each dynamometer diagram is determined.

6. The method for digital metering of oil wells in gas effecting operating conditions according to claim 1, characterized in that, Solving the system of equations yields the molar amount of free gas in the pump corresponding to each pumping indicator diagram. This includes solving the system of equations using the least squares method when the number of data points is greater than 3, to obtain the molar amount of free gas in the pump corresponding to each pumping indicator diagram.

7. A device for digital metering of oil wells in gas effecting mode, characterized in that, include: The gas mole quantity determining unit is used for determining the free gas mole quantity in the oil pump corresponding to each pumping work graph, and comprises the following steps: selecting multiple data points on the preset process segment curve of the lower stroke of each pumping work graph; constructing an equation group for solving the free gas mole quantity at the pump according to each data point and a model for solving the free gas mole quantity at the pump which is established in advance; and solving the equation group to obtain the free gas mole quantity in the oil pump corresponding to each pumping work graph. The model for solving the free gas mole quantity at the pump is as follows: ; wherein, is the pump load when the traveling valve is opened; is the cross-sectional area of the plunger; is the cross-sectional area of the pull rod connected with the pump; n is the mole number of the gas; Z is the compression factor; R is the gas constant; and T is the temperature in the pump; is the effective liquid production stroke, u is the displacement of an arbitrary point in the unloading process; F d is the plunger load when the lower stroke is performed. The prediction unit is configured to determine the liquid production of the pumping unit corresponding to each pumping diagram according to the free gas molar quantity in the pumping unit corresponding to each pumping diagram and a pre-established pumping unit liquid production model. ; wherein, is the liquid production of the pumping unit, is a leakage coefficient of the influence of pump leakage on pump efficiency, is a surface degassing crude oil volume coefficient, is a cross-sectional area of the plunger, is an effective liquid production stroke, is the free gas molar quantity. The final production volume determination unit is used to accumulate the wellhead production volume corresponding to each pumping indicator to obtain the cumulative production volume of the pumping unit wellhead.

8. The device for digital metering of oil wells in gas effecting mode of operation according to claim 7, characterized in that, It also includes: a setup unit for pre-establishing a production model for pumping wells according to the following method: Force analysis was performed on the plunger of the oil pump to obtain the internal pressure model of the pump during the preset process segment of the downstroke. Based on the pump load model when the traveling valve opens after the downstroke load is unloaded, the pump outlet pressure model is obtained. Based on the pump internal pressure model and pump outlet pressure model of the preset process segment of the downstroke, the pump internal pressure model when the traveling valve is open is obtained. Based on the gas state equation, the pump pressure model at different displacements of the plunger during the downstroke load unloading process is obtained. Based on the pump pressure model when the traveling valve is open, and the pump pressure model at different displacements of the plunger during the downstroke load unloading process, a model for solving the molar amount of free gas at the pump is obtained. Based on the model for solving the molar amount of free gas at the pump, the model for calculating the production volume of the pumping unit well is obtained.

9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the method in any one of claims 1-6 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program, when executed by a processor, implements the method in any one of claims 1-6.

11. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program, when executed by a processor, implements the method in any one of claims 1-6.

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