RU46536U1 - PLASTIC PRESSURE SUPPORT SYSTEM - Google Patents

Abstract

The proposal relates to the oil industry, and in particular to systems for waterflooding and maintaining reservoir pressure during the development of oil fields, which allow the cleaning of water pipes, tubing and bottom-hole zone of the oil reservoir in injection wells when operating low-permeability formations or that have worsened their performance due to contamination of the wellbore zones. The essence of the utility model is that the pipe insert is made descending from the wellhead with an inclination of 10 ° -15 ° relative to the horizontal, and the outlet pipes are made below and above, respectively, for sludge and oil. The technical and economic efficiency of the proposed reservoir pressure maintenance system is achieved by reducing the additional costs of cleaning injection wells of various injections in a single hydrodynamic system from contamination carried out by the spout from the bottom-hole formation zone, reducing the cost of flushing the supply high-pressure water conduits, and increasing the efficiency of injection wells with intermittent nature water injection. The use of this proposal allows using the existing RPM system to reduce the loss of injectivity of the reservoirs, increase the time between overhauls of the bottom-hole zone of injection wells and, as a result, save material costs for maintaining reservoir pressure.

Description

The proposal relates to the oil industry, and in particular to systems for waterflooding and maintaining reservoir pressure during the development of oil fields, which allow the cleaning of water pipes, tubing and bottom-hole zone of the oil reservoir in injection wells when operating low-permeability formations or that have worsened their performance due to contamination of the wellbore zones.

A well-known system for maintaining reservoir pressure, containing water conduits, pumps, distributing water conduits, injection wells (see book: VA Eronin and others. The operation of the reservoir water flooding system. - M .: Nedra, 1964, p.142-146).

The system allows you to transport water to each of the injection rows and further to the reservoir to replenish its energy spent in oil production.

The disadvantage of the system is that the system does not protect the bottom-hole formation zone from contamination by oil and solid suspended particles contained in the injected water, the accumulation of which in the bottom-hole zone of the formation leads to a decrease in injectivity.

Closest to the proposed one is the "System for maintaining reservoir pressure (RPM)" in the reservoirs of various permeabilities (RF Patent No. 38195 E 21 B 43/20. Publ. May 27, 2004 BI No. 15), containing pumps, water conduits, injection wells, purification devices located on water conduits of wells with formations of various permeability.

The system allows you to transport the required amount of water to various injection wells (simultaneously or sequentially) for injection into the reservoir, while it is possible to connect additional wells to the supply conduit using branches and perform additional purification of the outflow water when the injection is stopped and the water is redistributed between low and high wells.

The disadvantage of the system is that the treatment devices, made in the form of an expanded diameter tubing insert and located horizontally in the mouth zone of the injection wells, capture contamination of the spout water in the form of oil particles and solid sediment, but when renewed injection into the wells, a significant part of the captured

contaminants are removed from them by an initially intense stream of injected water and re-clogs the pore space of the reservoir. In addition, the placement of cleaning devices of this type is impractical in the estuary zone of highly receptive injection wells, since the outflow from them occurs at a very low flow rate, which does not allow the outflow to reach velocities capable of bringing out the clogging material on the day surface.

The technical task of the proposed device (system) is to reduce the loss of injectivity of the reservoirs, increase the time between cleaning the bottom-hole zone of injection wells and, as a result, save material costs to maintain reservoir pressure by eliminating the capture of sludge at the time of resuming injection from the treatment device.

The stated technical problem is solved by the described system for maintaining reservoir pressure in formations of various permeabilities, including pumps, water conduits, injection wells, treatment devices in the form of an expanded diameter pipe insert with outlet pipes, located on water conduits of wells with low permeability formations at the exit from the wellhead.

New is that the pipe insert is made descending from the wellhead with an inclination of 10 ° -15 ° relative to the horizontal, and the outlet pipes are made below and above, respectively, for sludge and oil.

Figure 1 shows a diagram of the proposed system for maintaining reservoir pressure.

Figure 2 shows an enlarged diagram of the proposed system for maintaining reservoir pressure in the immediate vicinity of the injection well.

In this case, in FIGS. 1 and 2: I — water injection into the formation, II — water spout from low permeability to high permeability formation;

In this case, in Fig.2: III - removed by washing pollution.

The reservoir pressure maintenance system includes head treatment facilities 1 (FIG. 1), pumps 2 as part of a cluster pumping station, water conduit 3, injection wells 4, which have opened high permeability formations, injection wells 5, which have opened low-permeability formations, treatment devices 6, each of which are made in the form of a downward inclined 10 ° -15 ° relative to the horizontal pipe element of expanded diameter and equipped with outlet pipes 7 and 8 (Figure 2), tubing 9, placed in the wells and hydraulically associated with treatment devices 6. In this case, treatment devices 6 are installed on water conduits 3

low-pressure injection wells 5 at the exit of the mouth and mounted on supports 10.

The system operates as follows.

Water prepared at the head treatment plant 1 (Figure 1) is pumped 2 into the water conduit 3 and pumped into the injection well 3 to maintain reservoir pressure in the reservoir 11 (Figure 2). When water is pumped into the injection well, the treatment device 6 practically does not change the quality of the injected water I due to the low concentration of oil particles and solid suspended particles (of the order of 10 ... 20 mg / l) and the insignificance of their size - of the order of 2 ... 20 μm.

When the pumps 2 are stopped (FIG. 1), the second part of the injected water is poured out from a low-permeability reservoir through a low-permeability injection well 5 into a water conduit 3 and from a water conduit 3 into a highly permeable reservoir, opened by a high-permeability injection well 4. The outflowing liquid contains a significant the concentration of contaminants (250 ... 1200 mg / l, and in individual portions reaching tens and hundreds of g / l) carried out from the bottom-hole zone 12 of the formation 11 and consisting of large oil globules and solid suspended particles stits. Moving along the tubing 9 (Figure 2), oil globules with solid particles additionally coalesce and coarsen, reaching sizes 1 ... 20 mm at the wellhead, and in some cases forming larger inclusions and jets. When a contaminated spout passes through a cleaning device 6 installed directly at the mouth of the injection well, which is a pipe element of a diameter expanded with respect to the horizontal pipe 3 and descending with a slope of 10 ° -15 ° relative to the horizontal, a larger parts of oil particles, as well as the precipitation of large solid particles in the sediment. Due to the slope of the installation by 10 ° -15 ° with respect to the horizontal, localization occurs under the influence of gravity of oil caught in the upper part 13 by the cleaning device 6 and sediment from solid particles in the lower part 14. The caught III water pollution in the form of oil accumulations 13 and solid sludge (sludge) 14 as they accumulate is removed from the treatment device 6 through pipes 7 and 8 for disposal. After the treatment device b, the purified water of the spout enters the water conduit 3 and then is discharged into the tank or fed through a highly-responsive well 4 into highly permeable reservoirs in a single hydrodynamic system. Thus, the system provides water purification from contamination during the outflow from a low-well well, which occurs when there is a hydraulic connection between the wells that have opened formations of different permeability, preventing the ingress of spout

into a water conduit, into a highly-responsive well and re-contamination of the bottomhole formation zone of low-responsive injection wells. The spout can also be organized forcibly by draining water from a water conduit to a tank at a cluster pump station.

An example of a specific implementation.

There is a group of highly responsive injection wells 4 with an injectivity of 800 cubic meters. meters per day at wellhead pressure of 5 MPa and a group of low-pressure injection wells 5 having injectivity from 50 to 200 cubic meters. meters per day at wellhead pressure of 10 MPa, in a single hydraulic system.

Water I is pumped by a pump 2 of a cluster pumping station through water conduits 3 to high-pressure injection wells 4 and low-pressure injection wells 5 with a flow rate of 1400 cubic meters. meters per day and pressure on the pump outflow 2-11 MPa (stream I).

When the pumps 2 are stopped, for example, in accordance with the schedule of periodic (cyclic) injection, a depression of up to 5 MPa is created in the hydraulic system. Wellhead pressure on low-pressure injection wells 5 drops to 5 MPa, and from wells 5 with low-permeability reservoirs, fluid II flows into conduit 3 and from the conduit to reservoirs with highly permeable reservoirs through highly-permeable reservoirs 4 in the amount of about 10 ... 20 cubic meters. meters. When the fluid moves from low-pressure injection wells 5 into the water conduit 3, contaminants are removed from the bottom-hole zone of the formation 12, which consists mainly of solid and oil particles, which, when moving along tubing 9, become larger at the approach to the wellhead. The maximum size of finely dispersed contaminants in the spout is 60 microns, and large inclusions up to 20 mm. The concentration of suspended solids is up to 200 mg / l. The concentration of oil particles varies in the range from 250 to 1200 mg / l, reaching a peak value of 143,000 mg / l (field data). Water with contaminants carried out from the bottom-hole zone of low-permeability reservoirs is cleaned on a treatment device 6, trapping oil and solid suspended particles that precipitate. Due to the slope of the installation by 10 ° -15 ° with respect to the horizontal, localization occurs under the influence of gravity of the oil caught in the upper part 13 and the sediment (sludge) from the solid particles in the lower part 14. The water from which 70% was removed pollutants, with residual fine contaminants, enters the water conduit 3 and then merges into the tank or is fed through a highly-responsive well 4 into highly permeable reservoirs in a single hydrodynamic system. Captured pollution III of water in the form of accumulations of oil 13 and solid sediment

(sludge) 14 as they accumulate is removed from the treatment device b through the pipes 7 and 8 for disposal.

The technical and economic efficiency of the proposed reservoir pressure maintenance system is achieved by reducing the additional costs of cleaning injection wells of various injections in a single hydrodynamic system from contamination carried out by the spout from the bottom-hole formation zone, reducing the cost of flushing the supply high-pressure water conduits, and increasing the efficiency of injection wells with intermittent nature water injection.

The use of this proposal allows using the existing RPM system to reduce the loss of injectivity of the reservoirs, increase the time between overhauls of the bottom-hole zone of injection wells and, as a result, save material costs for maintaining reservoir pressure.

Claims (1)

A system for maintaining reservoir pressure in formations of various permeability, including pumps, water conduits, injection wells, treatment devices in the form of an expanded diameter pipe insert with outlet pipes, located on the water conduits of wells with low permeability formations at the exit from the wellhead, characterized in that the pipe insert is made descending from wellhead with a slope relative to the horizontal, and the outlet pipes are made below and above, respectively, for sludge and oil.