A method for calculating oil-water two-phase fluid velocity in horizontal wells based on array turbines

Abstract

This invention discloses a method for calculating the velocity of oil-water two-phase fluid in horizontal wells based on an array turbine. The method comprises: preprocessing turbine data from a single-arm array imaging instrument; fitting the fluid velocity in the vertical direction; fitting the fluid velocity in the horizontal direction; and calculating the average velocity. In this method, when calculating the wellbore fluid velocity, not only is the velocity of the array turbine rotor projected onto the center vertical line of the wellbore cross-section to fit a polynomial relationship, but fitting is also performed in the horizontal direction, considering the characteristics of the fluid velocity in both directions, thereby improving the accuracy of the velocity calculation.

Description

Technical Field

[0001] The present invention relates to the field of dynamic monitoring in petroleum development, and mainly relates to a method for calculating the velocity of oil-water two-phase fluid in a horizontal well based on an array turbine. Background Art

[0002] Fluid velocity is a key parameter for calculating fluid flow within a wellbore. Stratified flow is common in the oil-water two-phase system of horizontal wells. In this scenario, fluid flow within the wellbore exhibits low velocities at the wellbore edges and high velocities at the wellbore center. Due to factors such as the density of the oil and water phases and well deviation, the flow velocities of the oil and water phases differ, resulting in the highest velocity not occurring at the wellbore center. However, stratified flow is observed in both pure oil and pure water layers. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for calculating the oil-water two-phase fluid velocity in horizontal wells based on array turbines. It mainly uses array turbines to perform oil-water two-phase measurements in horizontal wells and calculates the wellbore fluid velocity based on the turbine speed.

[0004] The object of the present invention is achieved by the following technical solution: A method for calculating the velocity of oil-water two-phase fluid in a horizontal well based on an array turbine, comprising the following steps:

[0005] Step S1, pre-processing the turbine data of the single-arm array imager, dividing the wellbore into grids, and calculating the local flow velocity of each turbine;

[0006] Step S2, fitting the fluid flow velocity in the vertical direction to calculate the flow velocity at any height on the Y axis;

[0007] Step S3, fitting the fluid flow velocity in the horizontal direction, and calculating the flow velocity on the straight line on the Y axis parallel to the X axis;

[0008] Step S4, fitting velocity curves in both horizontal and vertical directions and assigning values ​​to each grid, and calculating the average velocity of the wellbore section based on the velocity values ​​of the grid;

[0009] In step S2, the flow velocity of the fluid at the well wall is set to 0, and the local flow velocity of each turbine is projected onto the Y axis. A fourth-order polynomial curve is generated by the projected local flow velocity of each turbine and the two points at the well wall. The curve is fitted using a programming language, and the coefficients of the fourth-order polynomial are stored in the coeff array, that is:

[0010] V(y)=coeff[0]*y 4 +coeff[1]*y 3 +coeff[2]*y 2 +coeff[3]*y+coeff[4]

[0011] Then the flow rate step at any height can be obtained by this fourth-order polynomial.

[0012] In step S3, when the Y-axis value corresponding to a point P on the wellbore cross section is known, the calculation formula for the X-coordinate of a straight line passing through point P and parallel to the X-axis at the wellbore wall is:

[0013]

[0014]

[0015] Where CAL is the wellbore diameter, and y is the Y-axis corresponding value of point P;

[0016] At y, the velocity at the center of the wellbore is V(y), and the velocity at the wellbore wall is considered to be 0. The three point data are stored in obs, and a quadratic polynomial function is used to fit a curve using a programming language. The resulting quadratic polynomial function is:

[0017] V(x)=coeff′[0]*x 2 +coeff′[1]*x+coeff′[2]

[0018] This polynomial is the flow velocity calculation formula on the straight line parallel to the X-axis when the Y-axis value is y. Similarly, in the Y-axis range from 0 to CAL, a flow velocity calculation formula on a straight line parallel to the X-axis is calculated every 1 mm, and all grids in the entire wellbore cross section are assigned values.

[0019] Furthermore, in step S1, the turbine data preprocessing of the single-arm array imager includes:

[0020] Step S11: The horizontal pipe wellbore cross section is divided into sections, where each side of a single grid is 1 mm long and the cross-section diameter is the wellbore diameter; a two-dimensional coordinate system is established, with the vertical direction being the Y axis and the direction perpendicular to the Y axis and the fluid flow velocity being the X axis; the Y-axis height of the turbine projection after the imager rotates is calculated as follows:

[0021]

[0022] Where i is 1, 2, 3, 4, or 5; y′ i is the height of the i-th turbine after rotation, CAL is the well diameter, y i The default height of the i-th probe when the imager leaves the factory, ROT i is the rotation angle of the i-th probe;

[0023] Step S12: Input the starting speed V of each turbine calibrated in pure oil and pure water. t, response slope K;

[0024] Step S13, calculate the local flow velocity of each turbine, the formula is as follows:

[0025]

[0026] Where V i is the local velocity of the fluid near the i-th turbine, SP i is the measured response value of turbine No. i, K i is the response slope of the i-th turbine, V ti is the starting speed of the i-th turbine, V sPEED The speed at which the pull is measured is the cable speed.

[0027] Furthermore, in step S4, the average flow velocity of the cross section is calculated using the fluid velocity value of the wellbore cross section grid. The calculation formula is as follows:

[0028]

[0029] Where i is the grid number in the X-axis direction, j is the grid number in the Y-axis direction, and the following conditions are met: The grid can participate in the calculation when V m is the average flow velocity in the wellbore cross section, V i,j is the flow velocity value of the grid in row i and column j, S i,j is the area of ​​the i-th row and j-th column.

[0030] The beneficial effects of the present invention are as follows: in the present invention, the wellbore is first divided into grids, and then according to the characteristics of the stratified flow of the oil-water two-phase flow in the horizontal well, the flow velocity curve is fitted in the horizontal and vertical directions and a value is assigned to each grid, and finally the average flow velocity of the wellbore cross section is calculated according to the flow velocity value of the grid, thereby improving the calculation accuracy of the flow velocity in the oil-water two-phase flow in the horizontal well.

[0031] In the present invention, when calculating the wellbore fluid flow rate, not only is the flow rate of the array turbine rotor projected onto the central vertical line of the wellbore cross section to fit a polynomial relationship, but fitting processing is also performed in the horizontal direction, considering the characteristics of the fluid flow rate from two directions, thereby improving the accuracy of the flow rate calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the turbine distribution of the present invention;

[0033] Figure 2 is the velocity fitting curve under two-dimensional coordinates of the present invention;

[0034] Figure 3 Schematic diagram of the corresponding point of point P at the well wall of the present invention;

[0035] Figure 4 is a schematic diagram of three-dimensional flow velocity in a wellbore cross section of the present invention;

[0036] Figure 5 Schematic diagram comparing average flow velocity curves of example wells of the present invention. DETAILED DESCRIPTION

[0037] To help those skilled in the art better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with the accompanying drawings and specific examples. However, it should be understood that the drawings are for illustrative purposes only and are not to be construed as limiting the present invention. To better illustrate the present embodiments, certain components in the drawings may be omitted, enlarged, or reduced, and do not represent the dimensions of actual products. It is understandable that certain well-known structures and their descriptions may be omitted from the drawings. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present invention.

[0038] This invention discloses a method for calculating the velocity of oil-water two-phase fluid in horizontal wells based on an array turbine. The method uses a single-arm array imaging instrument with five micro-turbine rotors for well logging. The method uses the measured rotational speed data of each turbine rotor to calculate the local fluid velocity at each turbine location. This method then combines the flow characteristics of oil and water in a horizontal pipeline to calculate the average flow velocity of the mixed fluid. The method specifically includes the following steps:

[0039] Step S1, pre-processing the turbine data of the single-arm array imager, dividing the wellbore into grids, and calculating the local flow velocity of each turbine;

[0040] S11 divides the horizontal pipe wellbore cross section into 1mm squares per grid. The cross-section diameter is the wellbore diameter. A two-dimensional coordinate system is established, with the vertical direction as the Y axis and the direction perpendicular to the Y axis and the fluid flow velocity as the X axis. The projection of an array turbine on this two-dimensional coordinate system is shown as follows: Figure 1 As shown. The formula for calculating the height of the turbine projection on the Y axis after the instrument rotates is:

[0041]

[0042] Where i is 1, 2, 3, 4, or 5. i is the height of the i-th turbine after rotation. CAL is the well diameter, in mm. i The default height of the i-th probe when the instrument leaves the factory, in mm. i is the rotation angle of the i-th probe, in degrees.

[0043] S12 inputs the starting speed V of each turbine calibrated in pure oil and pure water t , response slope K.

[0044] S13 calculates the local flow velocity of each turbine using the following formula:

[0045]

[0046] Where V i is the local velocity of the fluid near the i-th turbine, in m / min; SP i is the measured response value of turbine No. i, in rps; K i is the response slope of the i-th turbine; V ti is the starting speed of turbine No. i, in m / min; V SPEED The speed of the pulling measurement, that is, the cable speed, is usually recorded as negative when measuring upward and positive when measuring downward, and the unit is m / min.

[0047] Step S2, fitting the fluid flow velocity in the vertical direction to calculate the flow velocity at any height on the Y axis;

[0048] In the vertical fluid velocity fitting step, based on multiphase pipe flow theory, the fluid velocity at the wellbore wall is set to 0. The local velocity of each turbine is projected onto the Y-axis. A fourth-order polynomial curve is generated from the local velocity of each turbine, the Y-axis value of 0, and the two points at CAL. The curve fitting is implemented using a programming language. The fitting code is as follows:

[0049] PolynomialCurveFitter fitter=PolynomialCurveFitter.create(4);

[0050] double[]coeff=fitter.fit(obs.toList());

[0051] obs.toList() is (0,0), (CAL, 0) and (y′ i ,V i ) The data of several points, the coefficients of the quartic polynomial are saved in the coeff array, that is:

[0052] V(y)=coeff[0]*y 4 +coeff[1]*y 3 +coeff[2]*y 2 +coeff[3]*y+coeff[4]

[0053] The flow velocity at any height can be obtained by the fourth-order polynomial. The fitted fourth-order polynomial curve is as follows: Figure 2 shown.

[0054] On the constructed wellbore cross section, at the same height, that is, when the Y-axis value is the same, the flow velocity is considered to be the same at this time, and this method is used to assign values ​​to the grid.

[0055] Step S3, fitting the fluid flow velocity in the horizontal direction, and calculating the flow velocity on the straight line on the Y axis parallel to the X axis;

[0056] In the step of fitting the fluid velocity in the horizontal direction, when the Y-axis value corresponding to a point P on the wellbore cross section is known, the calculation formula for the X-coordinate of the straight line passing through point P and parallel to the X-axis at the wellbore wall is: Figure 3 :

[0057]

[0058] Where CAL is the wellbore diameter in mm. y is the Y-axis value of point P.

[0059] At point P, the velocity at the center of the wellbore is V(y). The velocity at the wellbore wall is considered to be 0. The three point data are stored in obs, and a quadratic polynomial function is used to fit a curve using programming language:

[0060] PolynomialCurveFitter fitter=PolynomialCurveFitter.create(2);

[0061] double[]coeff=fitter.fit(obs.toList());

[0062] The resulting quadratic polynomial function is:

[0063] V(x)=coeff′[0]*x 2 +coeff′[1]*x+coeff′[2]

[0064] This polynomial is the flow velocity calculation formula on the straight line parallel to the X axis when the Y axis value is y. Similarly, in the Y axis range from 0 to CAL, the flow velocity calculation formula on a straight line parallel to the X axis is calculated every 1 mm, and all grids of the entire wellbore cross section are assigned values. The flow velocity of one wellbore cross section is as follows: Figure 4 As shown, the Y axis corresponds to Figure 1 The Y axis in the X axis corresponds to Figure 1 The X-axis and V-axis are the directions of fluid flow.

[0065] Step S4: Fitting velocity curves in both horizontal and vertical directions and assigning values ​​to each grid, and calculating the average velocity of the wellbore section based on the velocity values ​​of the grids.

[0066] In the step of calculating the average flow velocity, the fluid velocity value of the wellbore cross-section grid is used to calculate the average flow velocity of the cross section. The calculation formula is as follows:

[0067]

[0068] Where i is the grid number in the X-axis direction, j is the grid number in the Y-axis direction, and the following conditions are met: Only when the grid is V can it participate in the calculation. m V is the average flow velocity in the wellbore cross section, m / min. i,j is the flow velocity value of the grid in row i and column j, m / min. S i,j is the area of ​​row i and column j, m 2 .

[0069] In this example well, the comparison between the generated average velocity curve and the average velocity curve calculated by third-party software is shown in the figure below. Figure 5 As shown in the figure, it can be seen that the average flow rate calculated by the present invention has a good coincidence with the calculation result of the third party.

[0070] It is understandable that for those skilled in the art, any equivalent replacement or change to the technical solution and inventive concept of the present invention should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for calculating the velocity of oil-water two-phase fluid in a horizontal well based on an array turbine, characterized by: The following steps are involved: Step S1, pre-processing the turbine data of the single-arm array imager, dividing the wellbore into grids, and calculating the local flow velocity of each turbine; Step S2, fitting the fluid flow velocity in the vertical direction to calculate the flow velocity at any height on the Y axis; Step S3, fitting the fluid flow velocity in the horizontal direction, and calculating the flow velocity on the straight line on the Y axis parallel to the X axis; Step S4, fitting velocity curves in both horizontal and vertical directions and assigning values ​​to each grid, and calculating the average velocity of the wellbore section based on the velocity values ​​of the grid; In step S2, the flow velocity of the fluid at the well wall is set to 0, and the local flow velocity of each turbine is projected onto the Y axis. A fourth-order polynomial curve is generated by the projected local flow velocity of each turbine and the two points at the well wall. The curve is fitted using a programming language, and the coefficients of the fourth-order polynomial are stored in the coeff array, that is: V(y)=coeff[0]*y 4 +coeff[1]*y 3 +coeff[2]*y 2 +coeff[3]*and+coeff[4] Then the flow rate step at any height can be obtained by the fourth-order polynomial; In step S3, when the Y-axis value corresponding to a point P on the wellbore cross section is known, the calculation formula for the X-coordinate of a straight line passing through point P and parallel to the X-axis at the wellbore wall is: Where CAL is the wellbore diameter, and y is the Y-axis corresponding value of point P; At y, the velocity at the center of the wellbore is V(y), and the velocity at the wellbore wall is considered to be 0. ) The three point data are stored in obs, and a quadratic polynomial function is used to fit a curve using a programming language. The resulting quadratic polynomial function is: V(x)=coeff′[0]*x 2 +coeff′[1]*x+coeff′[2] This polynomial is the flow velocity calculation formula on the straight line parallel to the X-axis when the Y-axis value is y. Similarly, in the Y-axis range from 0 to CAL, a flow velocity calculation formula on a straight line parallel to the X-axis is calculated every 1 mm, and all grids in the entire wellbore cross section are assigned values.

2. The method for calculating the velocity of oil-water two-phase fluid in a horizontal well based on an array turbine according to claim 1, characterized in that: In step S1, the turbine data preprocessing of the single-arm array imager includes: Step S11: The horizontal pipe wellbore cross section is divided into sections, where each side of a single grid is 1 mm long and the cross-section diameter is the wellbore diameter; a two-dimensional coordinate system is established, with the vertical direction being the Y axis and the direction perpendicular to the Y axis and the fluid flow velocity being the X axis; the Y-axis height of the turbine projection after the imager rotates is calculated as follows: Where i is 1, 2, 3, 4, or 5; y′ i is the height of the i-th turbine after rotation, CAL is the well diameter, y i The default height of the i-th probe when the imager leaves the factory, ROT i is the rotation angle of the i-th probe; Step S12: Input the starting speed V of each turbine calibrated in pure oil and pure water. t , response slope K; Step S13, calculate the local flow velocity of each turbine, the formula is as follows: Where V i is the local velocity of the fluid near the i-th turbine, SP i is the measured response value of turbine i, K i is the response slope of the i-th turbine, V ti is the starting speed of the i-th turbine, V SPEED The speed at which the pull is measured is the cable speed.

3. The method for calculating the velocity of oil-water two-phase fluid in a horizontal well based on an array turbine according to claim 2, characterized in that: In step S4, the average flow velocity of the cross section is calculated using the fluid velocity value of the wellbore cross section grid. The calculation formula is as follows: Where i is the grid number in the X-axis direction, j is the grid number in the Y-axis direction, and the following conditions are met: The grid can participate in the calculation when V m is the average flow velocity in the wellbore cross section, V i,j is the flow velocity value of the grid in row i and column j, S i,j is the area of ​​the i-th row and j-th column.

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