RU2482265C2 - Setup method of oil well cluster, and device for oil collection and transport of oil well cluster - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: product of each individual oil well of the oil well cluster measured by means of group metering stations complete with a controller is supplied to an oil collecting header with a pump multiphase unit installed on it. At the outlet of the pump multiphase unit complete with an electric motor there performed in a real time mode is continuous monitoring of total product flow rate as per the oil well cluster in units of weight by means of a multiphase flow metre installed on the oil collecting header, between the outlet of the pump multiphase unit with an electric motor and a booster pump station and a controller in addition to it, as per a special programme built into it, there preformed is monitoring of differences of total component flow rates of the oil well cluster as a whole, and as per the deviation of difference beyond the limits of the set point specified in the controller, the operator takes this or that decision.

EFFECT: providing higher consumer properties of the site.

2 cl, 1 dwg

Description

The inventions relate to the oil industry and can be used in systems for collecting and transporting oil at exploited fields, as well as in measuring and monitoring the flow rate of wells at oil production facilities.

Oil fields, as a rule, are equipped as follows [1]. On the well pad there are several oil production wells equipped with downhole pumping equipment. All producing wells are connected to group metering units (GZU), providing periodic monitoring of the flow rate of each individual well.

The pressure in the oil collector at the well sites is selected so that it is sufficient for transporting oil to the booster pump station (BPS) or oil treatment unit (UPN), and, as a rule, varies from 0.4 MPa to 4.0 MPa Most of the oil collectors in Western Siberia operate at a pressure of 0.8 ... 2.2 MPa.

Well products from the well sites are supplied to the BPS, where a number of technological operations are performed, including partial separation of associated gas and (or) partial separation of produced water, followed by an increase in pressure for further transportation of oil to the oil treatment facility. Depending on the size of the field in the oilfield, there may be several CSNs or not a single one.

In the oil preparation point, the final preparation of the raw materials to the condition of goods is carried out with the subsequent delivery of oil to the Transneft trunk pipeline.

The distances from the well pads to the pumping station, the number of ponds, the pump station and their location are mainly determined by the number of wells and their location (drilling network), the distances from the bushes to the pump station and the pressure of the oil reservoir.

A known method [2] of a gravity-fed two-pipe collection of oil well products, in which gas is separated from oil, after which the separated gas is transported under its own pressure to the compressor station or to a gas processing plant (GPP), if the latter is nearby, and the liquid phase (oil with water) is sent to the second stage of separation. The oil-water mixture by gravity (due to the difference in leveling heights) enters the tanks of the local collection point, from where it is pumped to the tanks of the central collection point (CSP).

The method of gravity moving fluid reduces the energy consumption for its transportation. However, this method and device for its implementation have significant disadvantages:

- with an increase in the flow rate of wells or viscosity of the fluid (for example, due to an increase in water cut), the system requires reconstruction;

- to prevent the formation of gas accumulations in pipelines, deep degassing of oil is required;

- due to the low speeds of movement of products, waxing of pipelines is possible, leading to a decrease in their throughput;

- due to leaks in the tanks and difficulties with the use of gases of the 2nd separation stage, hydrocarbon losses with this collection system reach 2 ... 3% of the total oil production.

There is also known a method [3] of high-pressure single-tube production gathering of wells, in which it is transported over distances of several tens of kilometers due to high wellhead pressures (up to 6 ... 7 MPa). This method allows you to abandon the construction of precinct collection points and transfer oil separation operations to the central collection points.

The disadvantage of this method and device for its implementation is the fact that with a high gas content in the mixture (up to 90% by volume) in the oil collector, significant pressure pulsations of the mass flow rate of the liquid and gas occur. This, of course, violates the stability of pipelines, accelerates their destruction, and also adversely affects the operation of separators and instrumentation.

There is also a known method [4] of pressure single-pipe production of wells, which provides for single-pipe transport of oil and gas to local separation plants located at a distance of up to 7 kilometers from the wells, and transport of gas-saturated oils to the DSP.

Well production is first supplied to the site of the booster pump station (BPS), where at a pressure of 0.6 ... 0.8 MPa in the separators of the 1st stage, a part of the gas is separated, which is then transported to the GPP in an unpressor way. Further, oil with the remaining dissolved gas by centrifugal pumps is pumped to the site of the central collection point, where the final gas separation takes place in the separators of the 2nd stage. Then, after preparation, the gas is fed by compressors to the gas treatment plant, and the degassed oil by gravity (installation height of the 2nd stage separators 10 ... 12 m) enters the raw material tanks.

This method of collecting, transporting well products and its technical implementation is especially effective for oil fields in Western Siberia, where high rates of development of the oil industry have been achieved due to cluster drilling and construction [5].

We list the advantages of the pressure method for collecting wells and devices for its implementation:

- concentration on the DSP of the field equipment for the preparation of oil, gas and water for a group of fields located at considerable distances (up to 40 ... 100 km) from each other;

- reduction of capital investments and metal consumption of the collection system due to the refusal to build compressor stations and gas pipelines in the field for the transportation of low-pressure oil gas.

But this pressure method and the device for its practical implementation have a significant drawback that does not allow them to be applied (the method and device for its practical implementation) with greater efficiency in the exploited oil fields of Western Siberia. This disadvantage lies in the limited pressure in the oil collectors (0.8 ... 2.2 MPa) of fields in Western Siberia, which in turn limits the length of the reservoir from the well pads to the BPS or to the oil treatment plants (UPN).

Of the analogues, the closest technical solutions to the claimed method and device for its implementation are the method of arranging oil wells and a device for its implementation [6], which provide for an upgraded structure of the booster pump station with the so-called multiphase pumps. As the latter, twin-screw pumps are used, which can operate on a gas-liquid mixture with a free gas content at the pump intake of up to 50% ... 95%.

Domestic multi-phase pumps A3 2VV 63 / 25-50 / 25 and A5 2VV 63 / 25-50 / 25 (with shortened screws) have passed field tests and are used in the oil fields of OAO Tatneft, TNK-BP, LUKOIL and other

The multiphase pump type A3 2ВВ 63/25 provides for the transfer of oil-water emulsions with a gas content of up to 90%.

Such a method for arranging, for example, an oil well cluster, and a device for collecting and transporting oil in an oil well cluster can provide the following positive aspects:

- the ability to change (decrease) the working (excess) pressure on the well buffer, which in turn allows you to choose shut-off and control valves and other technological equipment for lower pressure;

- the choice of deep pumping equipment that develops less pressure at the wellhead, while maintaining the same productivity of the wells;

- reducing the pressure at the wellhead (back pressure on the formation) will increase the productivity of the wells - the return of the reservoir while maintaining a constant pressure in the system to maintain reservoir pressure;

- increasing the pressure in the oil collector (approximately from 0.6 ... 2.2 MPa to 3.0 ... 4.0 MPa) will reduce pressure losses during transportation of the oil and gas mixture by reducing the volume of free associated gas (part of the free associated gas will dissolve in oil ), which will lead to a decrease in the viscosity of the mixture and to a decrease in pressure pulsations in the pipeline;

- as a result of the installation of multiphase pumps in oil gathering reservoirs of the oil field, the number of pumping stations can be reduced or the need for their construction will disappear. In case of refusal from the pumping station, all the production of wells goes to the oil treatment facility, where all the necessary equipment for oil preparation is locally located, and the oil production facility can be placed closer to the oil delivery point;

- a decrease in the number of BPS will in turn lead to the abandonment of the construction of additional gas pipelines from the BPS, since the associated petroleum gas, together with the oil, enters the UPN, where the mixture is finally brought to a commercial product.

But this analogue, adopted as a prototype, has a significant drawback that does not allow the pressure method and device to be used to implement it with greater efficiency in the exploited oil fields of Western Siberia.

The fact is that currently in the oil industry of the Russian Federation there is a widespread implementation of the State Standards [7, 8], which, on the one hand, solves the problem of measuring the component flow rate (oil, gas, water) of well production using modern group metering units (GZU), on the other hand, does not give oil industry workers a tool for continuous monitoring of production volumes of both a single well and the well as a whole.

The drawback of all existing GZUs is that even after providing a periodic (according to a given program) reliable measurement of the production of each individual well for 4 ... 6 hours, oil workers do not receive real-time information about the operating modes of each well and a cluster of oil wells as a whole. The technical solution [6] adopted by us for the prototype does not solve this problem either.

The required technical result of the claimed industrial property is to provide well-known technical solutions with higher consumer properties by expanding their functionality.

The required technical result in terms of the arrangement of an oil well cluster, in which, according to the prototype method, all of its producing wells are connected to a group metering unit (complete with a controller) that provides periodic monitoring of the flow rate (for oil, gas and water) of each individual well and subsequent connection of the production of wells to the oil collector with a multiphase pump unit installed on it assembled with an electric motor, which supplies the products of the oil collector to the progress of the booster pump station is achieved by the fact that at the output of the pump multiphase unit with an electric motor, continuous monitoring (measurement) of total (over the well of oil wells) production rates (in oil, gas and water) in mass units using multiphase ( a non-separating) flow meter installed on the oil collector between the output of a multiphase pump unit with an electric motor and a booster pump station, and the controller using a special program built into it Amma monitors the differences in the total (over the well of oil wells) flow rates (for oil, gas and water), measured, respectively, by a group metering device (discrete measurement method) and a multiphase (non-separating) flow meter (continuous measurement method), and by the deviation of the flow rates difference beyond the limits specified in the controller settings (for oil, gas and water), the operator makes one or another decision.

The required technical result in terms of a device for collecting and transporting oil in an oil well cluster according to the prototype, comprising a group metering unit with a controller connected to an oil well cluster, the outlet of which is connected to an oil collector with a multiphase pump unit with an electric motor installed on it, and a booster pump station , achieved by the fact that on the oil collector, between the output of the pump multiphase unit with an electric motor and booster pump installed multiphase th (non-separating) flowmeter, the information output of which is electrically connected to the information input of the controller.

The required technical result is ensured by the presence of a combination of essential features (characterizing the proposed method for arranging an oil well cluster and a device for collecting and transporting oil in an oil well cluster) with undoubted applicability in industry, which suggests that the claimed objects meet the criteria of the invention.

The figure shows a device for collecting and transporting oil in an oil well cluster, which contains a group metering unit 1 with inputs for connecting oil wells in a cluster 2. From the output of a group metering unit, the integral flow rate for the oil collecting manifold 3 is fed to the input of the multiphase pump assembly assembled with an electric motor 4 . On the oil collector 3, between the output of the pump multiphase unit 4 and the input of the booster pump station 5, a multiphase (non-separation) flow meter 6 is installed, information the output of which is electrically connected to the information input of the controller (this connection is not shown in the figure).

The operation of the device for collecting and transporting oil in a cluster of oil wells is as follows.

Measured by separate flow rates (oil, gas, water) by group metering unit 1 in the cyclic survey mode, the production of each individual well (at the time of measuring the flow rate of a separate well, all other wells in the oil cluster 2 are connected to the oil collector 3) is supplied to the oil collector 3. The multiphase pump a unit with an electric motor 4 delivers under increased pressure the integral flow rate to the input of the booster pump station 5 through a multiphase (non-separation) flow meter 6, which produces continuous measurements (monitoring) the total consumption separately for oil, gas and water. We will take into account the fact that at the inlet of the multiphase (non-separating) flowmeter due to the increased pressure caused by the pump multiphase unit with an electric motor, the compressed product arrives (due to the increased compressibility and solubility of oil gas), which, firstly, creates the prerequisites for more accurate measurements made by a multiphase flow meter, and secondly, reduces hydraulic resistance in a sufficiently long oil collector. Known flow meters of multiphase flows (multiphase flow meters), designed specifically for oil companies [9, 10], which guarantee high technical, operational and metrological characteristics. Thus, for example, ROXAR type RFM MPFM-1900 flowmeters, with a decrease in volumetric gas content under operating conditions from 85 ... 97% to 0 ... 30%, reduce the relative error in measuring liquids (oil, gas) from 10% to 5%, and the absolute error in water - from 4% to 2%.

Thus, the calculations show that the presence of a multiphase pump on the wellbore capable of raising pressure from 0.25 ... 1.0 MPa to 4.0 MPa will allow the use of a multiphase (non-separation) flow meter operating in the continuous mode at the output of such a pump which provides more accurate measurements, and guaranteed by the manufacturers of flowmeters, measurement errors by mass ± 5%, free gas ± 10% and water cut ± 2-3% (absolute), are quite sufficient to control the total production rates of all oil well wells, and it is also determined I (to within ± 5%) deviation from the mode (stall feeding, stopping and the like) of the individual wells.

Our proposed device for collecting and transporting oil in an oil well cluster allows two methods to measure the same characteristics (flow rate) of the same object (oil well cluster) simultaneously, namely, discrete measurements (GDU) and continuous measurements (multiphase flow meter) . The presence of two consecutive measuring channels gives our device for collecting and transporting oil in an oil well cluster an additional function, namely, it allows monitoring differences in componentwise production rates for oil, gas and water, respectively, using two methods: discrete measurements (GDU) and continuous measurements (multiphase flow meter).

Let us consider this question in more detail from the point of view of the validity of this approach, when two time series are compared, one of them in the general case, a discrete series, or rather, continuously-discrete [11], and the second - continuous. According to the discrete-continuous readings obtained with the help of GZU, the daily component-by-unit production rates (for oil, gas and water) of each individual well in the oil well cluster and the total flow rate of the whole oil well cluster are extrapolated. Without addressing the issue of the accuracy of estimation (extrapolation) of daily production rates, it can be argued that, provided that the errors of the first method (GZU) and the second method (multiphase flow meter) are equal, the error of statistical estimates (for example, the arithmetic mean square deviation) of the daily production rate of a whole oil well cluster the second method will be much smaller and in the limit with an increase in the number of observations (which is feasible) will tend to zero [12].

Thus, monitoring the differences in the total component-wise flow rates (for oil, gas and water), measured by two methods (discrete and continuous) in the whole oil well cluster, will make it possible to track the dynamics of the processes of supply and measurement of production from wells to the booster pump station. For example, in the case of a deviation of the difference in one direction or another outside the specified settings, the operator will be able to decide whether to call the repair team to a particular bush, or give a command to shut off the bush or well.

In addition, the presence of two measuring channels on a wellbore of oil wells undoubtedly increases the reliability of the measurement as a whole.

Thus, in view of the foregoing, the claimed object is subject to protection as an industrial property object with the issuance of the relevant security document to the applicant.

INFORMATION SOURCES

1. Abramov G.S., Barychev A.V. Practical flow measurement in the oil industry. - M .: VNIIOENG OJSC, 2002. - 460 p. (p. 28, 29; 36 ... 40, 165 ... 171).

2. Korshak A.A., Shammazov A.M. Basics of oil and gas business. Textbook for high schools. Second edition, supplemented and corrected: - Ufa .: DesignPolygraphService LLC, 2002 - 544 p. (p. 193 ... 195).

3. In the same place (p. 195).

4. In the same place (p. 195 ... 196).

5. Pchelintsev Yu.V., Kuchumov P.P. Operation and modeling of frequently repaired directional wells. - M.: VNIIOENG OJSC, 2000. - 520 p. (P. 15).

6. Ivanovsky V.N., Darishchev V.I., Sabirov A.A., Kashtanov B.C., Beijing S.S. Equipment for oil and gas production: At 2 h. - M: State Unitary Enterprise Oil and Gas Publishing House of the Russian State University of Oil and Gas named after I.M. Gubkina, 2003 .-- Part 2. - 792 p. (P. 453 ... 462).

7. National standard of the Russian Federation. GOST R 8.615 - 2005. The state system for ensuring the uniformity of measurements. Measuring the amount of oil and gas extracted from the bowels of the earth. - M .: Standartinform, 2006 - 20 p.

8. The national standard of the Russian Federation. GOST R 8.647 - 2008 State system for ensuring the uniformity of measurements. Metrological support for determining the amount of oil and oil gas produced in the subsoil. - M .: Standartinform, 2009 - 12 p.

9. Description of the type of measuring instruments for the state registry. Multiphase Flow Meters MPFM 1900 VI and MPFM 1900 VI Non-Gamma. Registration No. 31090-06, 2006 - 4 s.

10. Description of the type of measuring instruments for the state registry. Multiphase flowmeters of the VX and FR models. Registration No. 21363-01.5 s.

11. Winshtein I.I., Abramov G.S., Mironov V.P. Development of methods and means of monitoring the process of pumping water into productive formations of oil fields in Western Siberia. - M.: VNIIOENG, 1978.- 47 p. (p. 33).

12. Burdun G.D., Markov B.N. Fundamentals of Metrology. Textbook for universities. Second edition, supplemented. - M .: Publishing house of standards, 1975 - 336 p. (145 ... 149).

Claims (2)

1. A method of arranging an oil well cluster, in which all of its producing wells are connected to a group metering unit (complete with a controller), which provides periodic monitoring of the flow rate (for oil, gas and water) of each individual well and subsequent connection of the well products to the oil collector with installed on it a multiphase pump assembly assembled with an electric motor, ensuring the supply of oil collector products to the input of the booster pump station, characterized in that at the pump outlet of a multiphase unit with an electric motor, real-time continuous monitoring (measurement) of total production rates (over a well of oil wells) of production rates (for oil, gas and water) in units of mass is carried out using a multiphase (non-separation) flow meter installed on the oil collector between the outlet multiphase pump unit with an electric motor and booster pump station, and the controller, according to the special program built into it, monitors the differences in total (for the bush oil wells) flow rates (for oil, gas and water), respectively measured by a group meter (discrete measurement method) and a multiphase (non-separating) flow meter (continuous measurement method), and by deviation of flow rates beyond the limits set in the controller (by oil, gas and water) the operator makes a decision. 2. A device for collecting and transporting oil in an oil well cluster, comprising a group metering unit with a controller connected to an oil well cluster, the outlet of which is connected to an oil recovery manifold with a multiphase pump unit with an electric motor installed on it, and a booster pump station, characterized in that on the oil collecting manifold, between the output of the pump multiphase unit with an electric motor and a booster pump station, a multiphase (non-separation) flow meter is installed, information the output of which is electrically connected to the information input of the controller.

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