How to realize multi-layer water injection in oil field injection wells?
With the extension of the oilfield development time, the energy consumption of the oil layer, the pressure drop, and the oilfield production decline, the oilfield development enters the water injection stage, and the formation energy is supplemented by water injection.
The water injection process, especially the layered water injection technology, is an important measure for the multi-layer water injection to complete the layered allocation plan and improve the water injection development effect; water injection can maintain the pressure of the oil layer.
To increase oil recovery and enhance oil recovery, stratified water injection should be implemented.
The packer is an indispensable part of water injection in oilfield exploitation, and its sealing performance is directly related to the quality of water injection in oilfields.
The packers used in traditional oilfields use layer-by-layer water injection; the connection between the upper joint of the packer, the well-flushing piston, and the outer center pipe is all tubing threaded connections, and the accumulated axial error is large, which affects the assembly quality; well-flushing pistons It is sealed with the central pipe, and the two conical surfaces are in contact with each other.
The sealing effect is poor, and leakage is easy to occur during water injection; the seal between the upper joint and the well-flushing sleeve is at the outer circumference of the end face groove of the upper joint, and the well-flushing sleeve is the multi-step parts are difficult to process; the seal between the upper joint, the well flushing sleeve and the well flushing piston adopts a single-channel double sealing ring seal, which has poor sealing performance and is likely to cause seal failure.
In view of this situation, Sanjack company developed the water injection packer, it has a simple structure and easy to be manufactured and has reliable sealing performance.
It is especially suitable for multi-layer water injection and well washing, which solves this problem well.
The inner diameter of the center tube of the packer is 55-60mm.
The connection between the packer joint, the cleaning piston, and the outer center tube is a common thread.
The original seal is designed on the sealing cone surface of the well cleaning piston and the center tube.
Unthreaded hole seal is used between the well wash sleeves and upper connection, the well wash sleeve is straight cylindrical, and the upper joint, well wash sleeve, and well wash piston adopt a double-channel single seal structure.
The structure is as follows:
When the packer reaches the predetermined depth of the well, the injection line injects high-pressure water into the well.
The high-pressure water enters the inner cavity of the upper and lower pistons through the upper and lower water inlet holes of the piston joint, pushes the piston upward, and compresses the sealant downward through the steel sleeve.
The sealants are separated by a spacer ring. The sealant expands radially to block the annular space between the tubing and casing.
At the same time, the steel sleeve goes up and is locked on the lock sleeve to prevent the sealant from rebounding in the axial direction.
Unpacking, so as to achieve the packer seat seal; when the packer is unpacked, the center tube is lifted up, the unpacking sleeve moves upward, the toothed part of the compression lock sleeve shrinks, the steel sleeve is released, and the sealant shrinks radially.
The annular space of the tubing and casing is re-communicated, and the packer is unsealed; when water injection is required, the packer is in the sealing state, and the water injection flows down the oil pipe into the packer and enters the center pipe and The annular space of the well wash sleeve pushes the well washing piston downward.
The outer cone surface presses the sealing element of the inner cone surface of the outer center pipe to block the annular space between the center pipe and the outer center pipe.
The water injection flows down from the center pipe into the lower end of the packer.
The water distributor enters the formation below the rubber barrel of the packer through the water distribution nozzle.
Because the well washing piston blocks the annular space of the central tube and the outer central tube, water injection cannot enter the formation above the rubber tube, thereby achieving layered water injection;
When the packer is in the sealing state, the cleaning fluid injected into the ground enters the well washing sleeve along the groove at the lower part of the oil jacket, pushing the well washing piston upward, and the water descends along the annular space of the central tube and the outer central tube.
The sleeve enters the annular space between the oil pipes, enters the oil pipes through the water distributor, and returns upward to the ground, thereby achieving the purpose of washing the well.
The product is simple in structure and easy to manufacture.
It can realize multi-layer and graded water injection and has reliable sealing.
It can further improve the development effect of water injection and meet the requirements of fine water injection in oil fields.
Contradictions, reduce the cost of later development and meet the production needs of casing deformed wells in the later stage of oilfield development.
