A testing method, testing device and testing system for the production and production capacity of an electric pump well in an offshore oilfield

Abstract

The present invention relates to a method, a testing device and a testing system for testing the production and production capacity of an electrical submersible pump well in an offshore oilfield. Aiming at the power supply mode of the offshore power grid, the method uses a wired downhole testing device to measure parameters such as the inlet and outlet pressures of the electrical submersible pump, as well as the motor temperature, vibration, etc., designs and installs a monitoring system for the production and production capacity of the electrical submersible pump well, calculates the liquid supply capacity of the oil reservoir by using the pump inlet pressure value and the static parameters of the oil reservoir, calculates the pressure value before the choke by using the outlet pressure and the calculation result of the pump efficiency, corrects it through the choke throttling model, and finally obtains a high-precision oil well test flow rate through the initial calculation of the oil well production in the offshore oilfield and the mutual calibration and correction of the production.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore oilfield oil well production testing, and in particular to a method, a testing device and a testing system for the production and productivity of an offshore oilfield electric pump well. Background Art

[0002] The development environment of offshore oil fields is harsh and costly, and the safety and automation requirements of the mining process are high. In addition, there are many factors that affect the production and productivity of a well, and the influencing factors are complex. Formation porosity and permeability, bottom hole pressure and oil supply boundary, wellbore size and completion method, rock anisotropy, fluid properties and seepage form, etc., will affect the production and productivity. At present, the method of obtaining oil well production data is mostly artificial separation measurement and installation of wellhead flowmeters. To obtain oil well productivity parameters, the current method is to conduct oil well productivity testing, that is, to conduct separate tracer method and other productivity testing construction after the construction of measures or when necessary. A single productivity test has the limitation of time validity, and analytical calculation and numerical simulation rely heavily on manual labor. In addition, due to the dispersed geographical location at sea, the high cost of platform operation, the cost of measurement and testing construction is expensive, and the time-sharing single test cannot meet the requirements of offshore digitalization and intelligent development. A method that can test the production and productivity of oil wells in real time is needed to facilitate timely understanding of reservoir conditions and make more accurate development adjustments.

[0003] In the prior art, there is a patent application with application number 200610164812.5 and titled "A method and system for measuring the production of oil wells, analyzing and optimizing the working conditions", which discloses a method and system for measuring the production of oil wells, analyzing and optimizing the working conditions. The method includes the steps of obtaining working condition data transmitted by a sensor arranged on an oil well pumping unit, and transmitting the working condition data to a working condition acquisition and monitoring unit through a wireless communication network, the working condition acquisition and monitoring unit receiving the working condition data, and transmitting the working condition data to a production measurement unit, and monitoring the operating state of the oil well, and after receiving the working condition data, the production measurement unit calculates the production of liquid according to the working condition data and the basic data of the oil well stored in the database. The specific method is to obtain active power by applying an energy consumption model, calculate the discharge pressure of the pump by applying a multiphase flow nozzle throttling model, and then calculate the production of liquid according to the relationship between mass flow rate and the active power and discharge pressure. Its signal transmission method is not suitable for the current development status of Shengli offshore, and since there is no downhole pressure testing equipment, the pressure used in the calculation is the converted pressure, so the error is bound to be large and its calculation method is different from this solution.

[0004] Therefore, further improvements were made to form the present invention. Summary of the invention

[0005] In view of this, on the one hand, the purpose of the embodiment of the present invention is to provide a method, a testing device and a testing system for testing the production and production capacity of an electric pump well in an offshore oilfield. This method is aimed at the power supply mode of the offshore power grid. By using a wired downhole testing device, parameters such as the inlet and outlet pressures of the electric pump, as well as the motor temperature and vibration, are measured. An electric pump well production and production capacity testing system is designed and installed. The liquid supply capacity of the reservoir is calculated by using the pump inlet pressure value and the static reservoir parameters. The pressure value before the choke is calculated by using the outlet pressure and the calculation result of the pump efficiency. After correction by the choke throttling model, through the way of initial calculation of the oil well production in the offshore oilfield and mutual calibration and correction of the production, finally, a high-precision oil well test flow rate is obtained. The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for testing the production and production capacity of an electric pump well in an offshore oilfield, comprising the following steps:

[0007] Obtain the steady-state data of the average fluid density ρ, the reservoir thickness h0, the height h1 of the electric pump from the bottom of the reservoir, the pump inlet pressure P2 of the electric pump unit, the pump outlet pressure P3, and the bottom hole pressure P1 and the reservoir pressure P0 under the zero-production condition before the first production is established after the installation of the electric pump unit is completed;

[0008] Obtain the static reservoir data, and calculate the initial test flow rate q by using empirical formulas and reservoir formulas wo ;

[0009] Calculate the pressure P4 before the choke by using the empirical formula derived from the Bernoulli equation, and calculate the final test flow rate q according to the choke throttling model o ;

[0010] Carry out production calibration by using the production calibration principle formula.

[0011] As a preferred technical solution of the embodiment of the present invention, the bottom hole pressure P1 and the reservoir pressure P0 are calculated by the formulas P1 = P2 + ρg(h1 - h0) and P0 = P2 + ρgh1.

[0012] As a preferred technical solution of the embodiment of the present invention, before obtaining the static reservoir data, it is judged whether the electric pump well reaches a stable state. The standard for reaching a stable state is that the fluctuation of the pump outlet pressure P3 and the wellhead oil pressure P5 is not more than 0.1 MPa within 1 hour, and the fluctuation of the flow rate q is not more than 5% within 1 hour.

[0013] As a preferred technical solution of the embodiment of the present invention, the static reservoir data, the empirical formulas and the reservoir formulas are specifically: calculating the reservoir pressure conductivity Oil storage energy value Reservoir formula The calculated initial test flow rate q wo, where μ is the fluid viscosity, K is the permeability, E i is the power integral function, f is the effective porosity, C is the comprehensive elastic coefficient, i2 is the slope of the pressure buildup curve without well shut-in, G is a constant between 6 and 7, r is the reservoir radius, and t is the production time.

[0014] As a preferred technical solution of an embodiment of the present invention, the empirical formula derived from the Bernoulli equation is Calculate the pressure P4 before the choke, and calculate the initial final test flow rate q according to the choke throttling model o , where γ = ρg, h2 is the height of the electric pump outlet from the wellhead, R is the gas-oil ratio, D is the choke diameter, and W is the water cut.

[0015] As a preferred technical solution of an embodiment of the present invention, before the production rate calibration, the production rate is revised and the parameters are updated. The method is as follows: If the absolute value of q o -q wo is less than 0.1×q o , then take the current q o as the oil production rate, and the calculation process ends; if the absolute value of q o -q wo is greater than 0.1×q o , then increase or decrease C by 0.1 times until the absolute value of q o -q wo is less than 0.1×q o , and the calculation process ends; after the first parameter value is taken, and in the continuous production process, the initial test flow rate q wo and the final test flow rate q o are calculated repeatedly.

[0016] As a preferred technical solution of an embodiment of the present invention, the method for production rate calibration includes the following steps:

[0017] S11. According to the set production rate calibration principle formula: |calibrated production rate - calculated production rate| < 0.3×calibrated production rate, where the calibrated production rate is calculated and determined according to the current relatively accurate artificial glass tube oil measurement method;

[0018] S12. If |calibrated production rate - calculated production rate| < 0.3×calibrated production rate, change the water cut W and the gas-oil ratio R in turn according to the weight until the calibrated production rate = calculated production rate, and the calibration process ends;

[0019] S13. If |calibrated production - calculated production| > 0.3 × calibrated production, change the comprehensive elastic coefficient C, effective porosity f, and permeability K in sequence according to the weights until |calibrated production - calculated production| = 0.3 × calibrated production. Then change the water cut W and oil-gas ratio R in sequence according to the weights until the calibrated production = calculated production, and the calibration process terminates.

[0020] An embodiment of the present invention also discloses a testing device for the production of an electrical submersible pump well in an offshore oilfield, which is installed in a string with a motor and an electrical submersible pump, and includes:

[0021] A wired downhole testing device, installed below the motor, for obtaining the corresponding data information in the above testing method;

[0022] A pressure transmission short joint, installed above the electrical submersible pump, and the wired downhole testing device is electrically connected to the pressure transmission short joint through a pressure transmission pipeline;

[0023] A wellhead oil pressure gauge, used to test the wellhead oil pressure at the outlet of the electrical submersible pump well;

[0024] A single-well flow metering device, used to test the flow rate at the outlet of the electrical submersible pump well.

[0025] In addition, an embodiment of the present invention further discloses a testing system for the production of an electrical submersible pump well in an offshore oilfield, which includes: a PLC main board;

[0026] A data processing unit is electrically connected to the PLC main board, has an automatic analysis ability, and can execute instructions to perform the above testing method;

[0027] A data storage unit is electrically connected to the PLC main board and the data processing unit respectively, for storing the corresponding data information in the above testing method, and can store according to different data acquisition frequencies. When there is a large deviation in the calculated data, it can automatically increase the data acquisition frequency to detect and correct the data in time;

[0028] An artificial input port is electrically connected to the PLC main board and the data processing unit respectively, and the artificial input port can input parameter values in an artificial input manner for forcibly correcting the values in the formula.

[0029] As a preferred technical solution of an embodiment of the present invention, the above testing system further includes a data display unit electrically connected to the data processing unit, which can transmit the data display result to the ground control center or the communication terminal of the operator in time.

[0030] The beneficial effects of the present invention are:

[0031] 1. This calculation method combines the analysis of unstable flow states with that of stable flow states. That is, it takes into account both the influence of the liquid supply capacity of the reservoir formation on the flow rate and the influence of the wellbore lifting process on the production rate, and realizes the combination and consideration of the two processes in the algorithm.

[0032] 2. This method establishes a calculation method with appropriate empirical formulas for wellhead and reservoir nodes. When applied, according to different blocks and production conditions, the correction method is simple. Under certain conditions, iterative method calculations can also be carried out to increase the calculation accuracy.

[0033] 3. This method gives an orifice throttling model suitable for offshore applications. When a pressure gauge is installed in front of the orifice, the test flow rate can be directly obtained, and the calculation is simple.

[0034] 4. This calculation method introduces the parameter of hydraulic diffusivity that characterizes the liquid supply capacity of the reservoir. At the same time, it gives empirical formulas and iterative calculation methods. Combining with the test data of a sensitive downhole wireline pump testing device, during the time when the reservoir pressure recovers after the electric pump stops power supply and stops operating, the hydraulic diffusivity is recalculated for use in the calculation of liquid production rate.

[0035] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, provides detailed descriptions as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is the initial calculation flow chart for the production testing of an offshore oilfield in an embodiment of the present invention.

[0038] Figure 2 It is the calibration calculation flow chart for the production testing of an offshore oilfield in an embodiment of the present invention.

[0039] Figure 3 It is the schematic diagram of the testing device for the production of an offshore oilfield electric pump well in an embodiment of the present invention.

[0040] Figure 4 It is the schematic structural diagram of the testing system for the production of an offshore oilfield electric pump well in an embodiment of the present invention.

[0041] In the figure: 1. Downhole wireline pump testing device; 2. Motor; 3. Electric pump; 4. Pressure transfer sub; 5. Pressure transfer pipeline; 6. Wellhead oil pressure gauge; 7. Single well flow rate measurement device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0044] The specific steps of the test method of the embodiment of the present invention are described as follows:

[0045] I. Calculation of the initial test flow rate q wo Calculation

[0046] S1. First, install a wireline downhole test device at the lower end of the electric pump unit. Through the wireline downhole test device, the pump inlet pressure P2 and the pump outlet pressure P3 can be monitored in a timely manner. At the same time, before the first production is established after installation, keep the well shut-in for 3 hours to obtain the steady-state data of the bottom hole pressure P1 and the reservoir pressure P0 under zero production conditions. The formulas are P1 = P2 + ρg(h1 - h0) and P0 = P2 + ρgh1, where ρ is the average fluid density, h0 is the reservoir thickness, and h1 is the height of the electric pump from the bottom of the reservoir.

[0047] S2. In the normal production state, judge whether the pump outlet pressure P3, the wellhead oil pressure P5, and the flow rate q reach a new stable state. The judgment criteria are that the pump outlet pressure P3 and the wellhead oil pressure P5 fluctuate no more than 0.1 MPa within 1 hour, and the flow rate q fluctuates no more than 5% within 1 hour. If the test conditions are met, it means that the stable state is reached, and proceed to the next step;

[0048] S3. When the stable state is reached, with a stable time of more than 4 days as the preferred solution, combined with the static reservoir data, use the empirical formula to calculate the reservoir pressure coefficient Reservoir oil storage energy value And the initial test flow rate q calculated by the reservoir formula , where μ is the fluid viscosity, K is the permeability, E wo , iis the power integral function, f is the effective porosity, C is the comprehensive elastic coefficient, i2 is the slope of the pressure buildup curve without well shut-in, G is a constant between 6 and 7, r is the reservoir radius, and t is the production time.

[0049] S4. Calculate the pressure P4 in front of the choke according to the empirical formula derived from the outlet pressure value P3 of the electric pump and the Bernoulli equation ; Calculate the initial final test flow rate q according to the choke throttling model where γ = ρg, h2 is the height from the outlet of the electric pump to the wellhead, q o is the oil production rate, R is the gas-oil ratio, D is the choke diameter, and W is the water cut. o

[0050] S5. If the absolute value of q o - q wo is less than 0.1×q o , then take the current q o as the oil production rate and terminate the calculation process; if the absolute value of q o - q wo is greater than 0.1×q o , then increase or decrease C by 0.1 times until the absolute value of q o - q wo is less than 0.1×q o , and terminate the calculation process. After completing the first parameter selection, repeat steps S3 and S4 during the continuous production process to revise the production rate and update the parameters, and give a prompt when the reservoir parameters are less than the production critical value.

[0051] II. Process of production rate calibration

[0052] Perform production rate calibration according to the principle of minimum change and the principle of strong primary update. The specific steps are as follows:

[0053] S11. According to the set production rate calibration principle formula: |calibrated production rate - calculated production rate| < 0.3×calibrated production rate, where the calibrated production rate is calculated and determined according to the current relatively accurate artificial glass tube oil measurement method;

[0054] S12. If |calibrated production rate - calculated production rate| < 0.3×calibrated production rate, change the water cut W and gas-oil ratio R in turn according to the weight until the calibrated production rate = calculated production rate, and terminate the calibration process;

[0055] S13. If |calibrated production rate - calculated production rate| > 0.3×calibrated production rate, change the comprehensive elastic coefficient C, effective porosity f, and permeability K in turn according to the weight until |calibrated production rate - calculated production rate| = 0.3×calibrated production rate, and then change the water cut W and gas-oil ratio R in turn according to the weight until the calibrated production rate = calculated production rate, and terminate the calibration process.

[0056] In this embodiment, a testing device for the production of an offshore oilfield electric pump well is also disclosed. It is installed in a string having a motor 2 and an electric pump 3, and includes: a downhole wireline testing device 1, a pressure transmission sub - section 4, a wellhead oil pressure gauge 6, and a single - well flow measurement device 7. Among them, the downhole wireline testing device 1 is installed below the motor 2 and is used to obtain the corresponding data information in the above - mentioned testing method. The pressure transmission sub - section 4 is installed above the electric pump. The downhole wireline testing device is electrically connected to the pressure transmission sub - section 4 through a pressure transmission pipeline 5 to achieve data transmission. The wellhead oil pressure gauge 6 is used to measure the wellhead oil pressure at the outlet of the electric pump well and is generally installed at the wellhead. The single - well flow measurement device 7 is used to measure the flow rate at the outlet of the electric pump well and is generally installed at the wellhead.

[0057] In addition, an embodiment of the present invention further discloses a testing system for the production of an offshore oilfield electric pump well, which includes: a PLC main board, a data processing unit, a data storage unit, an artificial input port, and a data display unit. Among them, the data processing unit is electrically connected to the PLC main board, has an automatic analysis ability, and can execute instructions to perform the above - mentioned testing method. The data storage unit is electrically connected to the PLC main board and the data processing unit respectively, and is used to store the corresponding data information in the above - mentioned testing method, and can store data according to different data acquisition frequencies. When there are large deviations in the calculated data, it can automatically increase the data acquisition frequency to timely detect and correct the data. The artificial input port is electrically connected to the PLC main board and the data processing unit respectively. The artificial input port can input parameter values in an artificial input manner and is used to forcibly correct the values in the formula. The data display unit is electrically connected to the data processing unit and can transmit the data display result to the ground control center or the communication terminal of the operator in a timely manner.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A testing method for the production and productivity of an electrical submersible pump well in an offshore oilfield, characterized in that, It includes the following steps: Obtain the steady-state data of the average fluid density ρ, reservoir thickness h0, height h1 of the electric pump from the bottom of the reservoir, pump inlet pressure P2 of the electric pump unit, pump outlet pressure P3, and bottom-hole pressure P1 and reservoir pressure P0 under zero production before the first establishment of production after the installation of the electric pump unit is completed; Obtain the static reservoir data and calculate the initial test flow rate q using empirical formulas and reservoir formulas wo ; The pressure P4 before the choke nozzle is calculated using the empirical formula derived from the Bernoulli equation, and the final test flow rate q is calculated according to the choke nozzle throttling model o ; Carry out production calibration using the production calibration principle formula; The bottom-hole pressure P1 and the reservoir pressure P0 are calculated through the formulas P1 = P2 + ρg(h1 - h0) and P0 = P2 + ρgh1; Before obtaining the static reservoir data, determine whether the electric pump well has reached a stable state. The standard for reaching a stable state is that the fluctuations of the tested electric pump outlet pressure P3 and wellhead oil pressure P5 do not exceed 0.1 MPa within 1 hour, and the fluctuation of the flow rate q does not exceed 5% within 1 hour; The static reservoir data, empirical formula, and reservoir formula are specifically as follows: calculating the reservoir pressure conductivity Oil storage energy value Reservoir formula Calculated initial test flow rate q wo , where μ is the fluid viscosity, K is the permeability, E i is the power integral function, f is the effective porosity, C is the comprehensive elastic coefficient, i2 is the slope of the pressure build-up curve without shut-in, G is a constant between 6 and 7, r is the reservoir radius, and t is the production time; The empirical formula derived from the Bernoulli equation is Calculate the pressure P4 before the choke nozzle. According to the choke nozzle throttling model Calculate the initial final test flow rate q o , where γ = ρg, h2 is the height from the outlet of the electric pump to the wellhead, R is the gas-oil ratio, D is the choke nozzle diameter, and W is the water cut; Before the production calibration, revise the production and update the parameters. The method is as follows: If the absolute value of q o -q wo is less than 0.1×q o , then take the q at this time o as the oil production, and the calculation process terminates; if the absolute value of q o -q wo is greater than 0.1×q o , then increase or decrease C by 0.1 times until the absolute value of q o -q wo is less than 0.1×q o , and the calculation process terminates; after the first parameter value is taken, repeat the calculation of the initial test flow rate q wo and the calculation of the final test flow rate q o during the continuous production process; The method for production calibration includes the following steps: S11. According to the set production calibration principle formula: |calibrated production - calculated production| < 0.3 × calibrated production, where the calibrated production is determined by calculating according to the current relatively accurate artificial glass tube oil measurement method; S12. If |calibrated production - calculated production| < 0.3 × calibrated production, change the water cut W and gas-oil ratio R in sequence according to the weight until the calibrated production = calculated production, and the calibration process terminates; S13. If |calibrated production - calculated production| > 0.3 × calibrated production, change the comprehensive elastic coefficient C, effective porosity f, and permeability K in sequence according to the weight until |calibrated production - calculated production| = 0.3 × calibrated production, and then change the water cut W and gas-oil ratio R in sequence according to the weight until the calibrated production = calculated production, and the calibration process terminates.

2. A test device for the production of an electric pump well in an offshore oilfield, installed in a string with an electric motor and an electric pump, characterized in that, It includes: A wired downhole pump testing device, installed below the motor, for obtaining the corresponding data information in the testing method as described in claim 1; A pressure transmission sub-joint, installed above the electric pump, and electrically connected between the wired downhole pump testing device and the pressure transmission sub-joint through a pressure transmission pipeline; A wellhead oil pressure gauge, for testing the wellhead oil pressure at the outlet of the electric pump well; A single-well flow measurement device, for testing the flow rate at the outlet of the electric pump well.

3. A test system for the production of an electrical submersible pump well in an offshore oilfield, characterized in that, It includes: A PLC main board; A data processing unit is electrically connected to the PLC main board, has an automatic analysis ability, and can execute instructions to perform the testing method as described in claim 1; A data storage unit is electrically connected to the PLC main board and the data processing unit respectively, for storing the corresponding data information in the testing method as described in claim 1, and can store according to different data acquisition frequencies. When there are large deviations in the calculated data, it can automatically increase the data acquisition frequency to detect and correct the data in time; An artificial input port is electrically connected to the PLC main board and the data processing unit respectively. The artificial input port can input parameter values in an artificial input manner for forcibly correcting the values in the formula.

4. The test system according to claim 3, characterized in that, It further includes a data display unit electrically connected to the data processing unit, which can transmit the data display result to the ground control center or the communication terminal of the operator in time.

Images