RU2212534C1 - Adaptive method of measurement and control of production rate of group of oil wells and device for method embodiment - Google Patents

Abstract

FIELD: well operation. SUBSTANCE: method consists in alternate measurement according to preset program of each well fluid quantity passed through well production meter for fixed interval of time with recalculation into daily output. Novelty consists in that in measuring of production rate of one of wells of group, measured in remaining well, of group are individual hydraulic power of deep-well pump and power consumed by electric drive. In this case, should their ratio vary by valve ΔK≥0,1K, where K is preliminarily determined numerical value for each well, well with such deviation of ratio K is taken for out of order measurement of its production rate. Device has vertical measuring vessel with side branch pipe for supply of well production to vessel, with upper branch pipe for withdrawal of liberated associated gas, and lower branch pipe for fluid discharge into gathering main of oil field, production supply pipeline, associated gas withdrawal pipeline, and pipeline of fluid discharge. Device also has electric transducers for monitoring the parameters in measuring vessel, and controller with multichannel (according to number of transducers) input for introduction of electric information signals of these transducers and controlling outputs, electrically controlled by controller well switch and three-way cock whose inlets are communicated with pipelines of associated gas and fluid discharge, and its outlet is communicated via check valve to gathering main of oil field. Device is provided with unit of active power meters whose inputs are connected with supplying busbars of deep-well pump electric drives of controlled oil wells, and outputs are connected to controller information inputs. EFFECT: provided estimation of technical conditions of electric drive-deep-well pump system in course of oil recovery. 2 cl, 1 dwg

Description

 The invention relates to the field of measuring and controlling the flow rate of oil wells and can be used in information measuring systems of production facilities, vehicles for the preparation of oil, gas and water.

 The known method [1] measuring the productivity of wells by measuring the average value of the flow rate for an adequately selected time, in which, in order to increase the accuracy of the measurement by establishing the control time during the measurement process, average flow rates and their mean square deviations at discretely increasing time intervals are determined, each the subsequent value with the previous one and complete the measurement after reaching the difference of two adjacent mean square deviations of the given set point.

Полученное значение σ_i сравнивается с заданным значением среднего квадратического отклонения результирующего среднего арифметического σ_y. При σ_y≥σ₁ измерение по скважине прекращается и подается сигнал на подключение очередной скважины. При σ_y<σ₁ увеличивается время измерения и вновь вычисляется среднее арифметическое измеряемой величины

и его математическое ожидание σ₂. Далее, после достаточно сложных процедур, вычисляется разность средних квадратических отклонений, вырабатывается новый критерий (здесь не приводится), и система снова имеет два исхода: или измерение заканчивается, или добавляется (увеличивается) время измерения. При увеличении времени измерения определяются новые значения

, и только при

где n - общее количество интервалов Δt_n измерения, входящих в заданную продолжительность измерения, равную t_n = Δt+nΔt_n, выдается полученное значение x_n.With this method, the optimal time for measuring the flow rate of each well from a group of wells is achieved using iterations (the method of successive approximations), starting the measurement of the flow rate with a known minimum time. According to the results of a number of measurements, the average value of the measured value and its mean square deviation are calculated

The obtained value of σ _{i is} compared with a given value of the mean square deviation of the resulting arithmetic mean σ _y . When σ _y ≥σ ₁ , the well measurement ceases and a signal is sent to connect another well. When σ _y <σ ₁ , the measurement time increases and the arithmetic mean of the measured quantity is again calculated

and its mathematical expectation σ ₂ . Further, after quite complicated procedures, the difference between the mean square deviations is calculated, a new criterion is developed (not given here), and the system again has two outcomes: either the measurement ends, or the measurement time is added (increases). With increasing measurement time, new values are determined

, and only at

where n is the total number of measurement intervals Δt _n included in a given measurement duration equal to t _n = Δt + nΔt _n , the resulting value x _{n is} output.

 A well-known device for measuring productivity of wells that implements the method [1], comprising a hydraulic switch, a flow meter, an information transmission unit, a total flow rate calculation unit for a given measurement time, an average flow rate calculation unit for a given measurement time, a reliable average flow rate output unit, a time generator unit intervals, the unit for forming the duration of the current test, the unit for calculating the mean square deviation of the arithmetic mean of the flow rate, the storage unit for the previous its standard deviation values and calculating the difference of adjacent values of standard deviations, the control unit measuring mode setting unit of the standard deviation of the difference arithmetic.

The complexity of this method and measurement device is obvious, and the selected criterion will be effective with a sufficiently large number of measurements at each iteration step. With a significant number of wells connected for alternately measuring the flow rate of the i-th well, this method causes an unreasonably long time to measure the flow rate of a group of wells. And if we take into account that to obtain true x _i, a number of measurements will be required to determine the daily production rate of each well, then the application of this method is hardly necessary.

 A known method of measuring well production, implemented in the operation of the device [2, 3], which consists in measuring the weight of a sealed cylindrical measuring tank suspended through a force sensor, periodically filled with products of alternately connected wells, and an indirect method for controlling the flow rate of wells by the electric drive power consumption is realized device [4].

 The most significant drawback of the method implemented by the device [2, 3] is a strict well survey program for measuring their production rate.

 The disadvantage of the device [2, 3] is its instrumental oversaturation and the complexity of the design.

 The closest technical solutions (prototypes) to the claimed method and device are the device and its method [5] for measuring the flow rate of oil wells. The known prototype device contains a vertical cylindrical separation tank with a preliminary gas sampling unit on the well production line, a three-way electric valve, three liquid level indicators, a check valve, an electric temperature sensor, an electric pressure sensor, a controller and a switch for wells.

 The method implemented by the prototype device [5] consists in alternately filling the measuring tank according to a given program with the separated oil well products and measuring the mass flow rate according to the known tank filling time, measured tank volume and the pressure drop of the liquid column between the lower and upper levels cut off by level sensors .

The disadvantages of the known technical solutions (method and device) for measuring and controlling the flow rate of a group of oil wells are:
the program is strictly defined by the sequence and duration (time) of the survey when measuring the production rate of each of the group of wells, not taking into account the dynamics of the flow rate for each well in the intervals between unit measurement cycles.

 Thus, the purpose of the claimed objects (otherwise, the required technical result) is to provide well-known technical solutions with higher consumer properties by providing adaptability while also ensuring the possibility of assessing the technical condition of the "electric drive - deep well pump" system.

 The required technical result in the inventive method, according to the prototype method, which consists in alternately, according to a given program, measuring the amount of fluid of each well passing through the meter for a fixed time interval, calculated in daily output, by the fact that when measuring the flow rate of one of the wells groups for the remaining wells individually measure the hydraulic power of the downhole pump and the power consumption of the electric drive, while if their ratio K changes I by ΔK ≥ 0.1K (where the initial K is predetermined and individually for each specific well), then a well with such a deviation in the power ratio is connected to an extraordinary measurement of its flow rate.

 As shown by bench and industrial tests of the inventive device and operating experience of the prototype device, the required technical result is achieved by the fact that the device for measuring the flow rate of oil wells, according to the prototype, contains a vertical measuring tank with a lateral branch pipe for supplying well products to it, with an upper branch pipe for discharge associated gas and a lower nozzle for draining the liquid, a temperature sensor in the measuring tank, sensors, respectively, the maximum and minimum allowable level of liquid spans in it, a hydrostatic pressure difference sensor in this tank, an overpressure sensor at the top of the tank cavity, and a controller with a multichannel, by the number of sensors, input for introducing electric information signals of these sensors into it and control outputs, product supply pipeline, pipeline associated gas discharge and fluid drain pipe, respectively, electrically controlled by the controller, a well switch and a three-way valve, the inputs of which are connected to the pipelines gas and liquid drain, respectively, and its outlet is intended to be connected, through a non-return valve, to the prefabricated oilfield manifold, is additionally equipped with a block of active power meters, the inputs of which are connected to the supply buses of the electric drives of the deep pumps of controlled oil wells, and the outputs are connected to the information inputs of the controller .

 The required technical result is ensured by the presence of a combination of essential features (characterizing the proposed method and a device implementing it for measuring and controlling oil production rates) of the above distinguishing features, and the non-detection of equivalent technical solutions with the same properties in patent and technical information sources implies that the claimed objects meet the criteria inventions.

 The drawing shows a schematic diagram of a device that implements an adaptive method of measuring and controlling the flow rate of a group of oil wells.

 The device consists of a vertical measuring tank 1 with a supply pipe 2 and, respectively, the gas and liquid discharge pipes 3 and 4; it also contains a temperature sensor 5, sensors 6 and 7 of the minimum and maximum allowable liquid level in the tank, a sensor 8 of the difference in hydrostatic pressure in the measured part of the tank, that is, the pressure difference along its height H filled with liquid to the maximum allowable level, gauge 9 at the upper point of the reservoir cavity, as well as a controller 10 with a multi-channel input 11 and outputs 12 and 13, pipelines 14, 15 and 16 for supplying products to the tank, removing gas and draining the liquid, respectively, are electrically controlled MODULES switch 17 wells and three-way valve 18. In addition, the device is provided with a supply of active power meters 19, 20 whose inputs are connected to the feeder buses electric pump controlled depth of oil wells are connected to data inputs of the controller.

 The device operates as follows. By means of the controller, that is, through the switch of the wells, by software, the oil wells are alternately connected to measure the flow rate.

 The production of one of the wells through the switch 17 and the product supply pipe 14 (which may be equipped with a gas pre-sampling unit; this unit is not shown in the drawing) enters the metering tank 1, where liquid and associated gas are separated. Three-way electrically operated valve 18 is in a position in which associated gas under excess pressure in the metering tank 1 is sent to the collection manifold, and the liquid fills the cavity of the metering tank.

Upon reaching the level of Y _{min the} controller, by the signal of the sensor 6, fixes the value of the hydrostatic pressure P ₁ of the liquid column in the tank by the current value I ₁ of the differential pressure sensor, and the measurement time t ₁ begins.

Upon reaching the liquid level U _{max the} controller, by the signal of the sensor 7, fixes the measurement time and hydrostatic pressure of the liquid column P ₂ according to the value of the output current I ₂ .

After the filling process of the cavity of the measuring tank from the level of U _min to the level of _{Max max, the} three-way electrically operated valve 18 switches to the "drain" position on the command from the controller, and the liquid begins to be displaced from the measuring tank by the compressed gas available in its measured part. In this case, the well from the measuring tank is cut off by a switch on the controller’s command.

 Recalculations of parameters fixed by the controller in the measuring tank into the flow rate are carried out according to well-known dependencies.

 In the case of installing between the lower and upper level sensors intermediate (not shown) level sensors, it is possible to change the volume of the measured tank, taking into account the different productivity of the measured wells.

где К - коэффициент, учитывающий кпд электропривода насоса, глубинного скважинного насоса и гидравлический кпд насоса;
N_гидр - гидравлическая мощность, развиваемая глубинным насосом;
N_потр - потребляемая электрическая активная мощность;
P_н (или Н) - перепад давления на насосе (в единицах давления или в метрах столба жидкости соответственно);
Q - расход прокачиваемой жидкости, кг/м³;
g - ускорение свободного падения, м/с.Simultaneously with the process of interrogating and measuring the production rate of wells in the controller, the current value of the power ratio K for each measured well is continuously calculated, determined by the formula

where K is a coefficient taking into account the efficiency of the electric drive of the pump, the downhole well pump and the hydraulic efficiency of the pump;
N _hydr - hydraulic power developed by a submersible pump;
N _consumption - consumed electrical active power;
P _n (or N) is the pressure drop across the pump (in units of pressure or in meters of liquid column, respectively);
Q is the flow rate of the pumped liquid, kg / m ³ ;
g - acceleration of gravity, m / s.

 During the survey of wells, the current value of K is compared with its numerical value of K (for each well) determined and stored in the controller memory at the time the well was put into operation. Based on the result of an extraordinary (control) measurement of the flow rate of a particular well and the result of parallel measurement of the power consumed by the electric drive, the controller adjusts the cumulative account of the produced products and provides, in addition, the possibility of timely detection of deviations in the operation of the pump unit as a whole.

 Thus, the proposed method and the device implementing it combine the principle of adaptive measurement of the production rate of wells and control of the technical condition of the electric drive-pump system.

 The set of essential features (including distinguishing ones) of the proposed adaptive method for measuring and controlling the flow rate of a group of oil wells and a device for its implementation ensures the achievement of the required technical result, meets the criteria of the "invention" and is subject to protection by a title of protection of the Russian Federation in accordance with the request of the applicant .

SOURCES OF INFORMATION USED IN THE DRAWING UP OF THE DESCRIPTION OF THE PROPOSED INVENTIONS
1. USSR, A.S. 751977, cl. E 21 B 47/10, 1976.

2. RF patent 2059067, M.cl. ⁶ E 21 B 47/10, 1993.

 3. Installation mass measuring transportable "ASMA-T-03-180-300A", 40100.00.00.000TO. Interregional Joint-Stock Company Nefteavtomatika (Ufa), Serafimovsky Experimental Plant of Automation and Telemechanics, 2000.

 4. Krichke V. O. The analyzer flow rate of a deep-well pump ADS-1 "Automation and telemechanization of the oil industry", M, VNIIOENG, 1978, 10. S. 14.

 5. Abramov G. S. et al. Automated measuring devices for measuring the flow rate of oil wells. NTZH "Automation, telemechanization and communication in the oil industry", 1-2, 2001, p.16-18, prototype.

Claims (2)

 1. An adaptive method for measuring and controlling the flow rate of a group of oil wells, which consists in measuring the amount of fluid of each well, which has passed through the meter in a fixed time interval, in turn according to a given program, recalculated into daily output, characterized in that when measuring the flow rate of one of the wells in the group, the remaining wells carry out an individual measurement of the hydraulic power of the downhole pump and the power consumption of the electric drive, while if their ratio changes by well ΔK ≥0.1K (where K is a predetermined numerical value for each well), then a well with such a deviation of the coefficient K is connected to an extraordinary measurement of its flow rate.  2. A device for measuring and controlling the flow rate of oil wells, containing a vertical measuring tank with a side pipe for supplying it with the production of a particular well, with an upper pipe for the discharge of associated gas and a lower pipe for draining the liquid (into the collection reservoir of the oil field), electrical sensors to control the temperature, maximum and minimum allowable levels of liquid in the measuring tank, the difference in hydrostatic pressure in this tank filled with liquid to the maximum permissible level, an overpressure sensor at the upper point of the reservoir cavity, as well as a controller with an input multi-channel for the number of sensors for introducing electrical information signals of these sensors into it and control outputs, a product supply pipeline, a gas outlet pipe and a liquid drain pipe, respectively, electrically controlled by a controller switch wells and a three-way valve, the inputs of which are connected to the pipelines of associated gas and fluid drain, respectively, and its output Erez return valve is connected to a collection manifold oilfield, characterized in that it is provided with a unit of active power measurers whose inputs are connected to the feeder buses electric pump controlled depth of oil wells, and the outputs are connected to data inputs of the controller.