RU2278248C2 - Method and device to control formation pressure keeping system - Google Patents

Abstract

FIELD: oil production industry, particularly to increase oil recovery by secondary method.

SUBSTANCE: method for pressure keeping in cyclic regime with the use of main high-capacity pump station and additional low-capacity pump station involves connecting the pump stations to delivery line through remote-controlled equipment of injection wells for a certain time necessary for fulfill pumping operation without flow throttling; supplying working agent of main pump station into all injection wells during common pumping cycle; stopping working agent injection in injection wells having high injectivity and disconnecting main pump station from delivery line; linking additional pump station to delivery line and completing working agent pumping in injection wells having lesser injectivity; regulating pumping operation performed by additional pump station with taking into consideration necessary working agent volume to be injected in each injection well to operate additional pump station at maximal performance factor; disconnecting injection wells after pumping operation termination from delivery line in injectivity decreasing order. The additional low-capacity pump station is displacement pump. Device for above method realization comprises supply pipeline, main high-capacity pump station and additional low-capacity pump station of displacement type connected to supply pipeline through shutoff fittings and to water-distribution unit through supply water pipe. Water-distribution unit is connected to shutoff and regulation fittings of injection wells by means of delivery line through shutoff means. Pressure and liquid volume sensors are installed at each injection well head. The sensors are linked with common controller via data transmission channel. Controller outputs are connected to voltage frequency converter input and to input of shutoff and regulation fitting control unit. Outputs of the control unit are connected with control inputs of shutoff and regulation fittings and shutoff fittings. Voltage frequency converter output is linked to additional pump station inlet.

EFFECT: decreased water content of oil deposit and reduced power inputs.

3 cl, 3 dwg

Description

The invention relates to the oil and gas industry and can be used to control the reservoir pressure maintenance system (RPM) in the development and operation of the oil and gas field.

A known method of managing the PPD system [1], which includes injecting a working agent in a cyclic mode through injection wells and taking oil through production wells, combining low-sensitivity wells into one group, injecting a working agent with a high-capacity pump into all injection wells during the first half-cycle of a cyclic regime, the termination of the injection of the working agent with a high-capacity pump and the pumping of the working agent with a low-capacity pump into the group of low-receiving injection squels in of the second half-cycle period in the zone prior to injection wells malopriemistyh reservoir pressure reaching equal current reservoir pressure at the site of development.

In the known invention, the disadvantage is that criteria are not defined for matching the hydrodynamic characteristics of injection wells, the characteristics of the pressure network and switchable pumps to ensure an energy-saving mode when managing the RPM system.

Closest to the set of features to the claimed method is a method of managing the RPM system [2], including the distribution of flows across injection wells and matching network characteristics with the characteristics of a cluster injection station (SPS), the introduction of remote-controlled shut-off devices on injection wells, the introduction of data collection and processing programs at the control room, maintaining reservoir pressure in a cyclic mode of operation, connecting each well to the pressure network for the time necessary for you completing her injection task during a given cycle without throttling the flow, coordinating the characteristics of the network and SPS by distributing the work of wells in the cycle. This method is adopted as a prototype.

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that the method does not optimize the operating modes of the SPS by determining the area of effective coordination of the hydrodynamic characteristics of injection wells and a pressure network, which leads to energy losses. The method does not provide the opportunity to optimize the management of the PPD system, since there is no regulation of the performance of the SPS in a wide range. The method does not provide a noticeable reduction in water cut, since the use of two pumping stations in the on and off modes inevitably leads to excessive injection volumes in some wells.

Known RPM system as part of a complex for oil production [3], including injection wells, oil wells, water distribution comb, control system, telemetric communication channel.

In the known invention, the SPS has a narrow control range, the efficiency of the SPS is significantly reduced when it is operating in modes other than nominal. The invention does not provide energy-saving modes of operation of the PPD system.

A well-known automated system for pumping a working agent and individual accounting of injection volumes into an injection well [4], including injection wells, a supply conduit connected to the common collector by the shortest distance in a straight line, pumping stations, telemechanics system equipment, liquid volume meters mounted at the mouth of each injection wells. This system is adopted as a prototype device.

The reasons that impede the achievement of the technical result indicated below include the fact that this invention does not provide optimal control of the PPD system. There is no SPS performance control unit and elements that can significantly reduce its energy consumption.

The essence of the method lies in the fact that they maintain reservoir pressure in a cyclic mode with the help of a high-capacity primary pumping station and an additional low-capacity pumping station, ensure that the characteristics of the discharge network are consistent with the characteristics of the primary and secondary pumping stations without flow throttling, and distribute the operation of the primary and secondary pumping stations and injection wells during the injection cycle, connect using remote control equipment production wells to the pressure network for the time necessary for them to complete the injection task, ensure that the main pumping station supplies the working agent to all injection wells during the joint period of the injection cycle, stops the main pumping station from pumping the working agent into the injection wells with greater injectivity, disconnect from the main pumping station, connect an additional pumping station to the pressure network, provide additional pumping of the working agent by the additional pumping station into injection wells with lower injectivity, regulate the supply of an additional pump station taking into account the necessary volumes of additional pumping of a working agent into each injection well, ensure the operation of the additional pump station in the region of maximum efficiency, sequentially, in order to reduce injectivity, disconnect the injection wells from the pressure network with performed by the injection task, as an additional pumping station of low productivity, use a volume pump ipa.

The essence of the device lies in the fact that in a device containing a supply network, a main pump station and an additional low-capacity pumping station of a volume type, connected by shut-off valves to the supply network and, through a supply pipe, to a water distribution unit connected via a pressure-reducing network through shut-off valves devices with shut-off and regulating equipment for injection wells, equipped with pressure sensors and the volume of injected fluid installed on the mouth of each injection important, a cluster controller with a channel for transmitting information from sensors to a cluster controller, a voltage frequency converter is additionally introduced, the input of which is connected to the output of the cluster controller, the second output of which is connected to the input of the control unit of locking and regulating equipment, connected to its outputs with the control inputs of locking and regulating equipment and valves, the output of the voltage frequency converter is connected to the input of a variable displacement low-capacity pumping station.

During the development and operation of deposits to maintain the required reservoir pressure, a certain amount of working agent must be continuously or cyclically supplied to the reservoir. At the same time, requirements are set not only for the total amount of agent injected into the formation, but also for the amount of agent injected through a certain group of wells, through individual wells or at different intervals of the formation of the same well. In connection with the change in hydraulic resistances on the way from the SPS to the reservoir and the magnitude of the required reservoir pressure in the injection zone, the pressure on the SPS varies over time. Therefore, along with measures to reduce hydraulic resistance in the injection network, the reliability of ensuring the required fluid flow into production wells, and the efficiency of the energy efficiency of the RPM system, depends on the change in the efficiency of the oil pump in the entire range of productivity control.

Achievable technical result - reduction of energy consumption by the RPM system, ensuring the possibility of its optimal automated control, reduction of water cut in the field.

In the proposed method of managing the PPD system:

1) maintain reservoir pressure in a cyclic mode using the main pumping station of high productivity and additional pumping station of low productivity;

2) coordinate the characteristics of the discharge network with the characteristics of the primary and secondary pumping stations without throttling the flows;

3) distribute the work of the primary and secondary pumping stations and injection wells during the injection cycle;

4) connect, with the help of telecontrolled equipment, injection wells to the pressure network for the time necessary for them to complete the injection task;

5) supply a working agent to all injection wells during the joint period of the injection cycle by the main pumping station;

6) stop the pumping of the working agent by the main pumping station into the injection wells with greater injectivity;

7) disconnect the main pumping station from the pressure network;

8) connect an additional pumping station to the pressure network;

9) carry out additional pumping of the working agent into injection wells with less injectivity by an additional pumping station;

10) regulate the supply of an additional pumping station, taking into account the necessary volumes of additional pumping of a working agent into each injection well and ensuring the operation of the additional pumping station in the region of maximum efficiency;

11) disconnect the injection wells from the pressure network with the task being performed on the individual volume of additional injection in series, in order of decreasing injectivity;

12) as an additional pumping station of low productivity use a volumetric pump.

Paragraphs 10-12 are new distinguishing features that determine the technical result achieved.

In the device, the technical result is achieved by introducing a voltage frequency converter, the input of which is connected to the output of the bush controller, the second output of which is connected to the input of the control unit of the shut-off and control equipment, connected to its outputs with the control inputs of the shut-off-control equipment and stop valves, the output of the converter voltage frequency is connected to the input of an adjustable low-capacity pumping station of volumetric type.

Figure 1 presents the structural diagram of a device for implementing the method of controlling the RPM system; figure 2 shows graphs of the characteristics of the pumping unit and diagrams of injection volumes when implementing the method of controlling the RPM system; figure 3 is a diagram of the costs of the working agent obtained by modeling and experimental studies.

The PPD system (Fig. 1) contains a power network 1, a main pumping station 2 with high capacity, an additional pumping station 3 with low capacity, volumetric type, shut-off valves 4, inlet conduit 5, water distribution unit 6, pressure network 7, shut-off devices 8, shut-off devices control equipment 9, pressure sensors 10, sensors 11 for the volumetric flow rate of the injected fluid installed at the mouth of each injection well 12, the cluster controller 13, the channel 14 for transmitting information from sensors 10, 11 to the cluster controller 13, pr voltage frequency generator 15, control unit 16 for locking and regulating equipment 9.

The source of the working agent is a supply network 1 connected to a water treatment plant (not shown in FIG. 1), supplying water to a high-capacity main pumping station 2 and an additional volumetric type low-capacity pumping station 3. Shut-off valves 4 allows you to connect and disconnect pump stations 2 and 3 to the inlet conduit 5 and the water distribution unit 6, which through the shut-off devices 8 supplies water to the pressure network 7. At the mouth of each injection well 12, shut-off and control equipment 9 is installed, which allows automatic operation connect the injection wells 12 to the pressure network 7, pressure sensors 10 and sensors 11 of the volumetric flow rate of the injected fluid. The output signals of the sensors 10 and 11 through the information transfer channel 14 are supplied to the cluster controller 13, which controls, using the control unit 16, the shut-off and control equipment 9, as well as using the voltage frequency converter 15 with an additional pump station 3.

The method of controlling the reservoir pressure maintenance system using the device is as follows.

First, the cycle time and the volume of the working agent pumped into injection wells 12 during the cycle are calculated from the parameters of the reservoir and production.

The signal from the first output of the cluster controller 13 switches the electrically operated shutoff valves 4 ("open-close") and connects to the mains supply network 1 of the main pumping station 2. The signal from the second output of the cluster controller 13 in the control unit 16 generates control signals for connecting electrically operated locking and control equipment 9 to the pressure network 7. The main pumping station 2 pumps the working agent through the water distribution unit 6 into all injection wells 12 during the joint th period of the injection cycle without throttling. Information about the volume of the injected working agent and the pressure at the mouth of the injection wells 12 from the outputs of the sensors 10, 11 through the information transfer channel 14 is supplied to the cluster controller 13.

When performing tasks on the volume of injection in each of the group of injection wells 12 with a higher injectivity (one well with the highest injectivity) Q ₁ from the second output of the controller 13 through the control unit 16 to the shut-off-control apparatus 9 (throttles or valves), a closing and shutdown signal of these injection wells from the pressure network 7. At the signal from the first output of the controller 13, the shutoff valves 4 are switched off, the main pump station 2 is disconnected from the supply network 1 and connected to the supply network 1 noy pumping station 3 the volumetric type, the choice of which is due to the need to separate the pump capacity control station 3 and the pressure at its output.

Preliminarily determine the required volume V _d re-injection of the working agent

V _d = V _P -V _C ,

where V _P - the planned volume of injection carried out for the entire cycle;

V _C is the injection volume in the joint period of the cycle.

and pace q of re-injection

where t _c is the cycle time;

t _with - time of the joint period of the cycle.

Using an additional pumping station 3, the working agent is additionally pumped into injection wells 12 with lower injectivity.

The supply of the additional pumping station is controlled taking into account the rate of re-injection of the working agent q, ensuring the maximum possible efficiency (efficiency) of the additional pumping station 3 for a given volume of re-injection.

Figure 2 shows the real characteristics of the additional pumping station 3 in terms of power consumption P, efficiency η, as well as the predetermined (solid lines) and adjusted (dotted lines) charts for re-injection into injection wells 12 with lower injectivity.

- объемы дозакачки в 1-ую скважину скважин 12 с меньшей приемистостью заданный и скорректированный соответственно; V₂ и

- объемы дозакачки во 2-ую скважину скважин 12 с меньшей приемистостью заданный и скорректированный; V₂ и

- объемы дозакачки в 3-ю скважину скважин 12 с меньшей приемистостью; Δη₁, Δη₂, Δη₃ - увеличение КПД дополнительной насосной станции 3.Moreover, V ₁ and

- volumes of additional injection into the first well of wells 12 with a lower injectivity given and adjusted, respectively; V ₂ and

- volumes of additional injection into the 2nd well of wells 12 with a lower injectivity given and adjusted; V ₂ and

- volumes of additional injection into the 3rd well of wells 12 with lower injectivity; Δη ₁ , Δη ₂ , Δη ₃ - increase in efficiency of the additional pumping station 3.

You can clearly see the reduction in energy costs by re-pumping the working agent into the wells 12 with less injectivity. At the same time, the required capacity (refueling volume per unit time) is not related to the load pressure (at the wellhead 12) due to the use of a volumetric pump. This makes it possible to increase the coverage factor, the degree of impact on the pore structures of the bottom-hole zone of the injection wells 12 with less injectivity and a general increase in the effectiveness of the impact on the formation.

When performing an individual task for injection into injection wells 12 with less injectivity, they are disconnected from the pressure network 7. Disconnection is carried out sequentially in order to reduce injectivity and, as a result, increase the hydraulic resistance of the "additional pump station - pressure network - injection well" system. An additional pumping station 3 maintains increased pressure at the mouth of the injection wells 12 with less throttle response.

Figure 3 is a flow chart of a working agent, showing an example of modeling and implementing the method and device using, as an additional pumping station 3, a volumetric type of an adjustable block-cluster pump station BKNS 160 × 400/20 with a three-plunger pump NTP-160 × 20.

The period of joint injection was 3.75 days, the volumetric flow rate was 1205 m ³ / day. The well with the highest throttle response is well No. 302. After shutting off the valve 9 at the wellhead No. 302, shutting off the pumping station and connecting the BKNS 400/160 to the water conduit 5, and replenishing the working agent into the remaining wells 12 for 7.05 days, the volumetric flow rate was 565 m ³ / day. Then well No. 105 was turned off and the flow rate was 365 m ³ / day, etc. The injection cycle was 27.75 days.

Using the method and device provides a reduction in energy costs of at least 25-30% due to the rejection of inefficient operating modes of the main pumping station 2 and optimization of the operating modes of the additional workstation 3, as well as reducing water cut in the field due to the individual approach to each injection well 12.

In addition, the invention provides optimal automated control of the PPD system and provides the following features:

- measurement of flow rates q _i and pressures p _i at the entrance to the injection wells with calculation of injection volumes w _i at the field or at the control point;

- construction and maintenance of the characteristics of injection wells p _i (q _i ) - adjustment, dynamics of changes;

- building and maintaining a set of network characteristics (injection wells, pressure network, water pipes, supply network) in coordinates P (Q) with the number of connected (open) wells from n to 1;

- the same in terms of the characteristics of the main pumping station 2 and the additional pumping station 3 in the coordinates P (Q) for both separate and parallel operation;

- combined characteristics of pumping stations 2 and 3 and the network, determining the operating point of the network.

Information sources

1. Pat. 2164591 RU, IPC E 21 V 43/20. A method of developing an oil deposit / G.F. Kandaurova, R.S. Nurmukhametov, R.X. Galimov, V.F. Fedin, S.V. Kandaurov (RU). - 2000123801/03; Claim 09/19/2000; Published March 27, 2001.

2. Pat. 2186954 RU, IPC E 21 V 43/20. The method of controlling the system for maintaining reservoir pressure / V.A. Gorbatikov, A.P. Palyanov (RU). - 200119331/03; Claim 07/19/2000; Publ. 10.08.2002.

3. Pat. 2165015 RU, IPC E 21 V 43/40, F 17 D 1/00. Complex for oil production / Yu.N. Makarkin, A.G. Gusev (RU). - 99113970/06; Claim 06/25/1999; Publ. 10.04.2001.

4. Paul. Maud. 22176 RU, IPC E 21 V 43/12. Automated system for injecting a working agent and individual accounting of injection volumes into an injection well / G.G. Ganiev, 3.N. Ziyakaev, V.A. Leader, V.R.Salikhov (RU). - 2001122967/20; Claim 08/16/2001; Publ. 10.03.2002.

Claims (3)

1. A method for controlling a reservoir pressure maintenance system, including maintaining reservoir pressure in a cyclic mode using a high-capacity primary pumping station and an additional low-capacity pumping station, matching the characteristics of the injection network with the characteristics of the primary and secondary pumping stations without throttling the flows, distribution of the main and additional pumping stations and injection wells during the injection cycle, connection using a teleoperator the installed equipment of injection wells to the pressure network for the time necessary for them to complete the injection task, the main pumping station supplying the working agent to all injection wells during the joint period of the injection cycle, stopping the main pumping station from pumping the working agent into the injection wells with higher injectivity, shutting down from the pressure network of the main pump station, connection to the pressure network of the additional pump station, additional pumping of the working agent by the additional pump station injection wells with lower injectivity, characterized in that the supply of the additional pumping station is regulated taking into account the necessary volumes of additional pumping of the working agent into each injection well and ensuring the operation of the additional pumping station in the region of maximum efficiency, sequentially, in order of decreasing injectivity, the injectors are disconnected from the pressure network wells with completed injection task. 2. The method according to claim 1, characterized in that as an additional pumping station of low productivity use a volumetric type pump. 3. The device for implementing the method according to claim 1 or 2, comprising a supply network, a main pumping station and an additional low-capacity pumping station of a volume type, connected by shut-off valves to the supply network and through a supply pipe to a water distribution unit connected via a pressure network shut-off devices with shut-off and control equipment for injection wells equipped with pressure and volume sensors of the injected fluid installed at the mouth of each injection well , a cluster controller with a channel for transmitting information from sensors to a cluster controller, characterized in that the device further comprises a voltage frequency converter, the input of which is connected to the output of the cluster controller, the second output of which is connected to the input of the control unit of shut-off and control equipment connected to its outputs with control inputs of shut-off and control equipment and valves, the output of the voltage frequency converter is connected to the input of the additional pump station.

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