Reservoir pressure maintenance system

FIELD: oil and gas industry.

SUBSTANCE: reservoir pressure maintenance system includes a water supply source, pumps, low-pressure water lines connecting the pump of the water supply source to booster pumps of injectors, which wellheads are equipped with shut-off and regulating valves. At that the low-pressure water lines are under maximum permissible pressure that exceeds the maximum permissible pressure at the input of the respective booster pump; the lines are equipped with pressure regulators. These pressure regulators ensure reduction of pressure at the input of the respective booster pump in the operation process up to a value lower that the maximum permissible pressure but not lower that the minimum permissible pressure for this pump. The pressure regulators are operating as downstream pressure controllers during limitation of the injection volume to one or several injectors or during their complete shut-down. The booster pump is designed for the input pressure as per the following formula.

EFFECT: improved reliability of the pumps operation and increase of their life between overhauls.

1 tbl, 1 dwg

 

The invention relates to the oil industry, in particular to the system of water injection into the reservoir for the purpose of oil displacement and reservoir pressure maintenance.

Known system of reservoir pressure maintenance (see tutorial Yu Seigman "Operation of systems for maintaining reservoir pressure at oil fields", Ufa: Publishing house of UGNTU, 2007. - Page 179-188), including pumps Bush pump station, manifold valves with flow meters and control valves, conduits connecting the collector of the manifold valves with separate injection wells of various injectivity and injection wells, grouped by conduits in accordance with the acceleration and pressure water injection.

The disadvantages of the known systems are a considerable length of high-pressure conduits and energy losses due to shut-off and control devices on the parts of the conduits or connected application at high-responsive injection wells because of the centrality of the regulation of water injection modes (pressure, flow) in the water lines, which set the flow rate of water through the conduits in General, control valves of manifold valves, the spray pump stations.

The closest in technical essence and achieved result of the discov�Oh is the system of reservoir pressure maintenance, described in downhole oil production (patent RF №2320861, E21B 43/20, publ. in bul. No. 9 dated 27.03.2008), including a network of low-pressure water lines, shut-off and control devices, injection wells, which are equipped on the mouths of booster pumps that allows you to set the water injection (pressure, flow rate) in each hole individually.

The disadvantage of this system is that in a network of low-pressure water conduits is necessary to maintain a pressure in the range from the minimum allowable, providing the pumping capacity of the pump, to the maximum, ensuring the solidity of its construction, at the entrance to each booster pump at the mouths of wells. However, large differences in the length of low-pressure conduits connecting both close and far remote in relation to the water source (Netlogon low-pressure water conduits) injection wells with booster pumps at their mouths can lead to an imbalance of pressure in the network of low-pressure conduits, namely to overcome the pressure losses in the network of conduits when water is supplied to the input of the booster pumps remote injection wells necessary to maintain the increased pressure at the entrance to a network of low-pressure water conduits, but at the entrance of booster pumps to injection wells close to a water source, due to the scarcity of pressure loss possible excess pressure values above the maximum allowed, ensuring their integrity and performance. A similar situation could occur when connecting to a network of low-pressure water mains wells with large differences of the elevations of the orifices, namely to overcome the hydraulic resistance of the liquid column in the network of conduits when water is supplied to the input of the booster pumps located high on the terrain profile of injection wells needed to maintain high pressure at the entrance to a network of low-pressure water conduits, but at the entrance of booster pumps to injection wells located at the same level or lower than the water source, due to the scarcity of pressure loss possible excess pressure values above the maximum allowed, ensuring their integrity and performance. When you change the mode of operation of a network of low-pressure conduits connected to the stop of the booster pumps at the mouth of one or several injection wells to accomplish the controlled cyclic exposure to water in developed areas of the reservoir, for conducting a planned or emergency works without stopping supplying the water to the low-pressure conduits, and the continuation of other booster pumps nagnetic�found wells of this system of reservoir pressure maintenance will require reconfiguring the mode of operation of the pump source of water supply to prevent excessive pressure build-up in the network of low-pressure conduits and accordingly the possible values exceeding the maximum allowable pressures at the entrances to the booster pumps at the mouths of wells. The operation of the pump under pressure exceeding maximum allowable may result in accelerated wear and breakage of the sealing elements of the pump casing, as well as overheating and failure of the electric drive motor, operating with higher load and consuming more electricity.

The technical task of the present invention are the protection of booster pumps at the mouth of the injection wells from the excess of actual pressure values in the low-pressure conduit at the inlet to the pump above the maximum allowable pressure values, ensuring their integrity and efficiency, increase the overhaul period of their operation.

The technical problem solved by the proposed system for maintaining reservoir pressure, comprising a water source, pumps, low-pressure conduits connecting the pump source water with booster pumps to injection wells, equipped with shut-off and regulating devices.

What is new is that the low-pressure conduits with the highest possible pressure exceeding the maximum allowable pressure at the inlet of the respective booster pump, is provided with an EGR�atrami pressure, reducing the inlet pressure booster pump below the maximum allowed, but not below the minimum allowed for this pump in operation.

The drawing is a flow diagram of the system of reservoir pressure maintenance.

The system for maintaining reservoir pressure comprises a source of water supply 1 to the pump 2, the water inlet on the low pressure conduits 3, 4, 5, 6, 7 to the inputs of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15, the mouth of which is equipped with shut-off valves 16, 17, 18, 19 respectively to control the flow of injection water. At the entrance to the booster pumps 8 and 10 injection wells 12 and 13 installed an additional pressure regulators 20 and 21, respectively.

The system of reservoir pressure maintenance works as follows.

From a water supply source 1 (e.g. treatment plant tanks, installation preliminary water discharge, water wells, river diversions, etc.) water pump 2 (usually dynamic centrifugal type) is served by low-pressure conduits 3, 4, 5, 6, 7 to the inputs of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15, the mouth of which is equipped with shut-off valves 16, 17, 18, 19 respectively to control the flow of injection water. Selection of the pump 2 water supply source 1, booster pumps 8, 9, 10, 11 about�swagat based on preliminary hydraulic analysis of the system of reservoir pressure maintenance based on the proposed modes of water injection into injection wells 12, 13, 14, 15 and low-pressure conduits 3, 4, 5, 6, 7, for example, programs for electronic computers "Software graphical construction of a network system maintain reservoir pressure" (certificate of the Russian Federation on registration No. 2010616781, registered. 12.10.2010 G., the Registry of the computer programs), "Programme of pumps selection and calculation of water distribution in the system of reservoir pressure maintenance" (certificate of the Russian Federation on registration No. 2010617037, registered. 21.10.2010, the Registry of the computer programs). According to the results of hydraulic calculations, which simulate various modes of operation of injection wells 12, 13, 14, 15, determine the ranges of variation of the pressure at the pump outlet 2 water supply source 1 and respectively at the inputs of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15, reveal injection wells, at the entrance of booster pumps where the pressure change will not go beyond the minimum and maximum permissible values according to the specifications of booster pumps 9 and 11 (in the drawing, for example, this injection well 13 as having the greatest altitude relative to the pump 2 water supply source 1 and respectively having the largest pressure loss at overcoming the difference of the elevations relative to the water supply source 1, and injection well 15 ka� the furthest from the water source 1 respectively having the largest pressure loss along the length of the conduit 7 from the water supply source 1). Also identify the injection wells 12 and 14, which in operation is possible overpressure at the entrance to their booster pumps 8 and 10, respectively, above the maximum allowable pressure according to the specifications data of booster pumps 8 and 10 (in the drawing, for example injection wells 12 and 14 because of their proximity to the water source and the lower elevation of the mouths). For this reason, to limit the maximum value of the inlet pressure booster pumps 8 and 10 injection wells 12 and 14 set the pressure regulators 20 and 21 on the low-pressure conduits 4 and 6 of the booster pumps 8 and 10. Pressure regulators 20 and 21 operate on the principle of "after you", i.e. limit the maximum pressure at the entrance to the booster pumps 8 and 10 respectively at no more than asked them in reference values of pressure (the pressure set in the pressure regulator as possible thereafter), and are configured so that when simultaneous injection wells 12, 13, 14, 15 do not produce the limiting pressure at the inputs of booster pumps 8 and 10 injection wells 12 and 14, since the pressure, coming to the pressure regulators 20 and 21, should be exhibited below them in the settings.

Production�capacity of the pump 2 water supply source 1 is chosen from the condition of ensuring the required water flow in low pressure conduits 3, 4, 5, 6, 7 in total costs of injection wells 12, 13, 14, 15, the pressure at the outlet of the pump 2 should provide a pressure not less than the minimum value at the input of the booster pump 11 injection well 15 as the most remote from the water supply source 1 and at the inlet of booster pump 9 injection well 13 as wells having the greatest altitude relative to the pump 2 water supply source 1. For booster pumps 8 and 10 injection wells 12 and 14, respectively, because of their proximity to the source of water supply (compared to the injection well 15) and the lower elevation of the orifices (compared to the injection well 13) the values of inlet pressure can be close to the maximum allowed values, ensuring their integrity and performance, but not to exceed them. In General, the dependence of the pressure at the inlet to the booster pump 8, 9, 10 or 11 injection wells 12, 13, 14 or 15 of the value of the pressure developed by the pump 2 water supply source 1, can be defined by the formula (1) when the condition (2):

where PI- the inlet pressure booster pump, MPa;

PYVES- the pressure at the pump outlet of a water supply, MPa;

P ST- loss of pressure to overcome the difference in elevation relative to the pump source of water (static pressure), MPa

PHYDR- pressure losses along the length of low-pressure water lines from the water source to the inlet of booster pump injection wells (hydraulic losses), MPa

PRD- pressure loss in the pressure regulator, MPa;

PMIN- the minimum pressure at the inlet to the booster pump, MPa;

PMAX- maximum allowable pressure at the inlet to the booster pump, MPa.

When you change the mode of the system for maintaining reservoir pressure caused by restriction of flow injection into one (for example, 13 or 15) or more injection wells (for example, 13 and 15) or full stop (for example, in accordance with the schedule of periodic (cyclic) injection either for repair or research on injection wells 13 and/or 15, etc.) decreases the total flow of injected water in operating injection wells, the pump 2 starts to operate in a mode with reduced performance and increased the pressure and consequently increases the pressure at the outlet and further into the low-pressure conduits 3, 4, 5, 6, 7 and the inputs of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15. For example, when about�the climate of the work of the booster pump 11 and disabling operation of injection wells 15 is an increase in pressure at the inputs of booster pumps 8, 9, 10 injection wells 12, 13, 14. Thus for booster pump 9 injection wells 13 the increase of pressure at its input will not exceed the maximum allowed value (the selection condition of the pump 2 water source 1 working with all injection wells is provided a pressure not less than the minimum value at the input of the booster pump 9 injection wells 13), and for booster pumps 8 and 10 injection wells 12 and 14, the pressure increase on their inputs does not occur due to the operation of the pressure regulators 20 and 21. When running a booster pump 11 injection wells 15 pressure values and costs back to its initial state.

Thus, the application of the proposed system maintain reservoir pressure allows the injection of water into injection wells 12, 13, 14, 15 booster pumps 8, 9, 10, 11 with the water flow from the water source 1 via the low-pressure conduits 3, 4, 5, 6, 7, and to protect the inputs of booster pumps 8 and 10 against excessive pressure exceeding maximum allowable values as defined by the technical characteristics of booster pumps, by setting before them the inputs of the pressure regulators 20 and 21, working on the principle "behind" while limiting the flow injection into one or more injection wells or a full stop.

When�EP specific performance

From the power supply 1 pump type 2 CNS 13-40-5 water with a total flow rate of 345 m3/day, and a pressure of 3.3 MPa is served by low-pressure conduits 3, 4, 5, 6, 7 to the inputs of booster pumps 8 and 11 type UNCW 80-1150 injection wells 12 and 15, and also to the inputs of booster pumps 9 and 10 type UNCW 125-900 injection wells 13 and 14 (initial state).

According to the results of hydraulic calculation (conventionally not provided), in which simulated various modes of operation of injection wells 12, 13, 14, 15, identified injection wells 13 and 15, at the entrance of booster pumps 9 and 11 the change in pressure will not go beyond the minimum and maximum permissible values according to the specifications of booster pumps 9 and 11 (in the drawing, for example, is injection well 13 as having the greatest altitude relative to the pump 2 water supply source 1 and respectively having the largest pressure loss at overcoming the difference of the elevations relative to the source of water supply 1, and injection well 15 as the furthest from the water source 1 respectively having the largest pressure loss along the length of the conduit 7 from the water supply source 1). Also identified injection wells 12 and 14, which in operation is possible exceedance of davleniya log into their booster pumps 8 and 10 above the maximum allowable pressure according to the specifications data of booster pumps 8 and 10 (in the drawing, for example - this injection well 12 and 14 because of their proximity to the water source and the lower elevation of the mouths). For this reason, to limit the maximum value of the inlet pressure booster pumps 8 and 10 injection wells 12 and 14 set the pressure regulators 20 and 21 (for example, low pressure regulators for use on waste water "rnds" or similar), working on the principle "behind" on the low-pressure conduits 4 and 6 of the booster pumps 8 and 10.

Taking into account the difference of the elevations of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15 relative to the pump 2 water supply source 1 and the pressure loss in the low-pressure conduits 3, 4, 5, 6, 7 inlet pressure booster pump 8 injection well 12 is 2.8 MPa with flow injection 90 m3/day. Similarly, the pressure at the inlet of booster pump 9 injection wells 13 is 0.5 MPa at a flow rate of pumping 75 m3/day, inlet pressure booster pump 10 of the injection well 14 is 2.8 MPa with flow injection 95 m3/day, inlet pressure booster pump 11 injection wells 15 is 1.3 MPa at a flow rate of pumping 85 m3/day. Minimum and maximum allowable pressure for booster pumps 8, 9, 10, 11 are 0.1 MPa and 5 MPa.�tively. Accordingly, the setpoint pressure in the pressure regulators 20 and 21 are exposed at the level of 2.9 MPa and the initial state of the system to maintain reservoir pressure does not produce limitation of pressure at the inputs of booster pumps 8 and 10 injection wells 12 and 14, since the pressure that comes on the pressure regulators 20 and 21, below, exhibited them in settings.

When disconnecting, for example, injection wells 15 schedule periodic (cyclic) injection in case of disconnection of pressure regulators 20 and 21, the total flow rate of the pump 2 is reduced to 300 m3per day, the outlet pressure increases to 3.7 MPa, while the input of booster pumps 8 and 10 injection wells 12 and 14, the pressure exceeds the maximum allowable of 0.3 MPa, and the flow rate of injection into injection well 12 is increased to 105 m3/day, injection well 13 is increased to 85 m3/day, injection well 14 is increased to 110 m3per day.

In the event of a power injection well 15, but when the pressure regulators 20 and 21 with the setpoint pressure limitation at the level of 2.9 MPa, the pressure at the inputs of booster pumps 8 and 10 injection wells 12 and 14 is 2.9 MPa (by operation of the pressure regulators 20 and 21, respectively), the inlet pressure booster pump 9 injection well 1 is 1.2 MPa. The consumption of water injection into injection wells 12 and 14 remains virtually unchanged because of the low (0.1 MPa) pressure at the entrance to the booster pumps 8 and 10, the flow rate of injection is increased to 90 m3/day only in injection well 13 because of an increased pressure at the inlet of booster pump 9.

The change in the cost of water injection and pressure at the discharge of the pump 2 water supply source 1 and the inputs of booster pumps 8, 9, 10, 11 injection wells 12, 13, 14, 15 are shown in the table.

As can be seen from the table, at the entrance of booster pump 9 injection wells 13 a pressure change within the minimum and maximum values of pressure and for injection wells 12 and 14 through the use of pressure regulators 20 and 21 installed on the inputs of booster pumps 8 and 10, it eliminates the excess of the actual pressure over the maximum allowable pressure value.

Thus, the proposed system maintain reservoir pressure allows to increase the duration of the turnaround time and service life of booster pumps 8, 10 injection wells 12, 14 to 25% and reduce costs for their repair up to 15% (field data).

Technical and economic efficiency of the proposed system of reservoir pressure maintenance is achieved through �of predotvrasenija overpressure at the inlet of booster pumps to injection wells in the course of their operation under variable operating modes, when the actual pressure in the low pressure conduits at the inlet of booster pumps may exceed the allowable limits defined by the technical characteristics of booster pumps.

Use this proposal allows for a small additional capital costs by using existing system maintain reservoir pressure to increase the overhaul period of operation of booster pumps through the installation of pressure regulators at the inlet of booster pumps, to reduce the cost of repairs booster pumps, injection wells, thereby to optimize the cost of water injection wells and, as a result, reduce material costs for the maintenance of reservoir pressure.

The system for maintaining reservoir pressure, comprising a water source, pumps, low-pressure conduits connecting the pump source water with booster pumps to injection wells, the mouth of which is equipped with shut-off and control devices, characterized in that the low-pressure conduits with the highest possible pressure exceeding the maximum allowable pressure at the inlet of the respective booster pump equipped with pressure regulators, providing the possibility of reducing the inlet pressure booster pump below the maximum allowed, but not any�e is the minimum acceptable for this pump in operation, with the principle of their work "behind" while limiting the flow injection into one or more injection wells or a full stop, and the booster pump is designed for inlet pressure according to the expression:
PI=PYVES-(PST+PHYDR+PRD),
where PI- the inlet pressure booster pump, MPa;
PYVES- the pressure at the pump outlet of a water supply, MPa;
PST- loss of pressure to overcome the difference in elevation relative to the pump source of water supply static pressure, MPa;
PHYDR- pressure losses along the length of low-pressure water lines from the water source to the inlet of booster pump injection wells - hydraulic losses, MPa;
PRD- pressure loss in the pressure regulator, MPa.



 

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2 cl, 2 dwg

FIELD: oil field development, particularly for ones with nonuniform reservoirs.

SUBSTANCE: method involves drilling injection and production wells; flooding oil reservoir and extracting oil out of well; defining more exactly geologic aspects on the base of drilling results; designing and drilling additional wells with horizontal bores or drilling horizontal bores from existent wells; determining location of reservoir drive zone boundaries; calculating volume of dead oil located near drive zones; drilling horizontal bores from existent wells located near drive zones and/or new wells with horizontal bores located in above zone, wherein horizontal bores are drilled in direction perpendicular to drive zone boundaries.

EFFECT: improved oil recovery.

2 dwg, 1 ex

FIELD: oil industry.

SUBSTANCE: method includes drilling vertical product and force wells, extracting oil from product wells, forcing working agent through force wells, making side horizontal shafts in force wells, forcing working agent through side horizontal shafts of force wells. Additionally, side horizontal shafts are made in extraction wells. Oil is taken through side horizontal shafts of extractive wells. With pressure in the well, decreased for 5-10% from hydrostatic pressure, all side horizontal shafts are made by washing away rock under pressure of fluid of around 15-20 mPa. Direction of all side horizontal shafts is set to be parallel to rows of wells.

EFFECT: higher oil yield.

1 ex, 1 dwg

FIELD: oil production industry, particularly enhanced recovery methods for obtaining hydrocarbons.

SUBSTANCE: method involves drilling production and injection wells and maintaining formation pressure; performing seismic works to determine volumetric routing of natural macrocrack system with lateral and depth routing; forming production and injection macrocracks of above system; drilling wells to corresponding macrocracks and forming producing well-macrocrack systems for oil production and injection well-macrocrack for formation flooding or production well-macrocrack for oil production and system including vertical and/or horizontal multibranch wells for formation flooding or injection well-macrocrack system for formation flooding and system including vertical and/or horizontal multibranch production wells for oil production or production well-macrocrack system, injection well-macrocrack system and system including vertical and/or horizontal multibranch production and injection wells.

EFFECT: increased efficiency, oil recovery and production well injectivity, as well as increased sweep efficiency and oil recovery ratio.

1 dwg

FIELD: oil production industry, particularly oil deposit development.

SUBSTANCE: method involves pumping working agent, namely water, in two stages. The first stage is performed with the use of power pumps. The second one is carried out by means of hydraulic measuring pumps, which are used to convert injection pressure created by power pumps. If it is necessary to increase pressure in water lines used to deliver water to separate injection wells pressure is regulated in accordance with necessary water volume to be injected in wells on the base of collecting properties of oil formations in bottomhole formation zones. This is performed by providing change in pump piston diameter and stroke ratios in the first and the second sections of hydraulic measuring pumps, which are selected on the base of hydraulic resistance variation depending on water flow velocity. Parameters characterizing injection system operation are simultaneously measured and efficiency of the method and equipment operation is detected from above characteristics.

EFFECT: increased efficiency of oil bed development due to energy-saving equipment and technique usage for formation pressure maintaining.

2 cl, 2 dwg

FIELD: enhanced recovery methods for obtaining hydrocarbons.

SUBSTANCE: method involves flooding production bed through injection wells with the use of pump units. In the case of terrigenous porous productive bed flooding acoustical sound resonators with resonance frequency setting are installed in injection line. This eliminates amplitude of alternating low-frequency liquid pulsation sound generated by pump units. Method also involves providing constant compression mode in productive beds and frontal oil drive from productive bed.

EFFECT: increased operational reliability.

1 ex, 3 dwg

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