RU2531011C1 - Formation cut-off procedure for work over without well kill operation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method includes a separate running in to the well of a pipe string with packer system, sensor units (when required) to control parameters of the well state, a pilot-controlled electrical or electromechanic valve and downhole wet contact unit connected and disconnected electrically and mechanically. The pilot-controlled electrical valve is intended for opening/closure for delivery of the formation fluid to overpacker area of the well. A separate running in is made for the pipe string in the lower part of the downhole wet contact unit connected and disconnected electrically and mechanically by an electrical line ensuring data transfer from monitoring sensors, supply and transfer of commands to the pilot-controlled electrical or electromechanic valve from the ground station or running in is made for the pipe string equipped with a deep well pump, electric submersion pump or a shank of any other type fixed in the lower part of the pump equipment, or a telemetry unit located under the pumping unit, the upper part of the downhole wet contact unit connected and disconnected electrically and mechanically. The electrical line may be connected at the wellhead by a separate cable line when submersible electric drive (sucker rod pump, free-flow production method, etc.) is not used in the downhole equipment or in composition with the fourth core of the submersible cable for electric pumps up to an electric drive of the pump equipment and then by a separate cable or from the zero point of the submersible motor or from telemetric system of the submersible motor. The shank may be equipped with emergency isolation device. Upon matching of the upper and lower part of the downhole wet contact unit connected and disconnected electrically and mechanically the electrical coupling between the ground station for the formation operational parameters and the pilot-controlled valve is set and in result there is a option to control and measure parameters of the well state and to cut off the formation fluid when maintenance and repair operations are performed for the pumping equipment.

EFFECT: option to perform lifting of the pumping equipment for maintenance and repair without well kill operations.

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Description

The invention relates to the oil industry and can be used in underground maintenance of wells equipped with electric centrifugal (or other types) pumps, in order to preserve the reservoir properties of the reservoir.

A known method of closing a shut-off valve when removing an electric centrifugal pump from a fountain well (analogue) and a device for its implementation. RF patent No. 2204695, E21B 34/06. Published May 20, 2003

The method of closing the shutoff valve when removing the electric centrifugal pump from the well is based on actuating the shutoff assembly, depressurizing the wellhead and lifting the pumping equipment. The locking unit of the shutoff valve is actuated when the wellhead and the tubing string are sealed at the command of the surface by creating pressure inside the tubing string to move the electric centrifugal pump upward. The lower part of the electric centrifugal pump is connected to the pusher of the shutoff valve. Using a power cylinder (hydraulic jack), the electric centrifugal pump is moved from the position that ensures the communication of the reservoir with the cavity of the well, to the position in which the reservoir is disconnected from the cavity of the well. The position of the hydraulic jack is fixed by a device controlled from the surface by a waste shut-off element. After shutting off the reservoir, the wellhead is depressurized and the submersible equipment is removed.

The disadvantages of the method of closing the shutoff valve when removing the electric centrifugal pump from the fountain well and a device for its implementation are: the need to pull off the electric centrifugal pump without lifting the tubing when closing the shutoff valve: additional loads on flange connections; the complexity of the work when lowering the electric centrifugal pump to ensure the reliability of opening the shutoff valve without sealing the wellhead.

Known controller-shutoff Sharifov (analogue), designed to disconnect the reservoir from the well. RF patent No. 2229586, E21B 34/06. Published May 27, 2004

The Sharifov controller-shutoff consists of a housing with one or more upper and lower throughput channels, external sealing elements and a latch. At least one regulating body in the form of a bellows or piston chamber with a rod and / or a shutter with a corresponding seat is located inside the latch. According to the invention, the valve is installed under and / or above the seat, and / or inside the seat, and / or between the seats, freely and / or spring-loaded, and / or rigidly connected to the stem of the bellows or piston chamber. The chamber is made without or with a unit for charging it with compressed gas and is placed in the housing from above and / or below, respectively, in the direction of its rod down and / or up, so that the chamber of the bellows or piston without the unit for charging can be hermetically isolated or hydraulically connected to the cavity of the body or space behind the housing, while a force-controlled spring element is installed in the chamber.

The disadvantages of the borehole shutoff valve are: work with the shutoff regulator is complicated by individual spring selection (spring compression ratio) to ensure reliable valve operation, as well as pressure calculations in the bellows chamber.

Known downhole shutoff valve (analogue), designed for tight shutoff of the wellbore during repair work. RF patent No. 2112863, E21B 34/06. Published on June 10, 1998

The downhole valve consists of two discs. They have coaxial holes and the ability to turn relative to each other to separate the holes. The locking unit also has a control mechanism. Grooves are made in the mating surfaces of the disks. They form a cavity hydraulically connected by a channel with a nadklapannym space. The operation of the borehole valve of the cutter is based on the principle of a revolving mechanism.

The disadvantages of the downhole shutoff valve are: the lack of a device for determining the position of the hole of the disk during rotation; for use in the arrangement with an electric centrifugal pump, it is necessary to modify the device to rotate the disk to the desired angle.

The closest in technical essence to the claimed (prototype) is a method of operating a well using an electrically and mechanically controlled downhole wet and dry plug and disconnect unit, including the descent and installation of a pipe string with a packer arrangement, sensor control units of formation parameters controlled by electric or electromechanical valves that regulate or cut off the flow of fluid from the formations into the well, while the valves are controlled through a docked block to "wet contact", and the communication line is a submersible pump motor power cable laid along the column or additional communication channel (RF patent №2500882, opub.10.12.2013).

This method of operating wells is applicable for simultaneous and separate operation of wells that open two or more layers and cannot be used for ongoing well repairs to replace downhole pumping equipment.

The present invention is aimed at maintaining reservoir productivity during routine well repair.

An object of the invention is to create a method that allows to eliminate the harmful effects of the killing solution on the reservoir due to the controlled shutdown of the reservoir’s reservoir and the unhindered change of pumping equipment in wells with abnormally low and high reservoir pressures.

The problem is solved in that in the method of cutting off the formation for underground repairs without killing the well using an electrically and mechanically controlled plug-and-play wet contact block, including the descent and installation of a pipe string with a packer arrangement, blocks of sensors for monitoring formation parameters, controlled electric or electromechanical valves, regulating or cutting off the flow of fluid from the reservoir into the well, while the valves are controlled through poked wet contact block, and the communication cable is the power cable of the electric motor of the submersible pump or an additional communication channel laid along the column, according to the invention, the packer assembly containing the packer, armature, electrical or electromechanical valve blocking the passage channel in the packer, the sensor unit and the lower block of the wet contact disconnectable electric block, an electric submersible pump, to the bottom of which or to the shank with the emergency disconnect device the upper block of the wet contact disconnectable electric block, connect the upper and lower wet contact blocks, open the electric or electromechanical valve by controlling through the wet contact block, operate the formation with a submersible pump until it becomes necessary to carry out underground repairs, and then produce closing an electric or electromechanical valve by controlling through a wet contact unit, an electric submersible pump, to the bottom of which or the shank with the emergency disconnecting device is fixed to the upper block of the wet contact disconnected electric unit, removed from the well and underground repair is carried out, after which the operation of lowering the electric submersible pump is repeated.

A wet contact type connection is used to provide a reliable electrical connection and disconnection in downhole conditions with an electric valve and a sensor unit located in a packer system. Power supply, control, information transmission of the electric valve and the sensor block through the wet contact connection can be carried out through the power cable of the submersible pump (from the “zero point” of the electric submersible motor) or through a cable separately laid along the tubing string and pump equipment (or as an extra braided cable with a power cable).

The invention is illustrated by drawings, where figure 1 and 2 schematically shows a schematic diagram of a method of cutting off a reservoir for underground repairs without killing a well for options for controlling an electric valve: through a power cable of a submersible pump 3 and through an additional channel 21.

Figures 1 and 2 show the layout diagrams after the descent of all parts of the equipment and the wet contact docking, supplemented by a borehole pump 5, a submersible motor 6 with a telemetry unit (TMS) 7, a power cable КРБК 3, or an additional channel from a geophysical cable 21 fixed on pipes 2 with fixing belts 4 or protectors 22.

A “wet” contact consists of two blocks - a block of the upper “wet” contact 8 and the lower “wet” contact 14, the connection of which in borehole conditions allows to obtain a reliable electrical contact. An example of a particular case in surface conditions is the plug-socket connection. In borehole conditions, this compound is complicated by the presence of an electrically conductive medium (borehole fluid), high pressure and temperature, and the presence of suspended solids that gradually settle on the bottom of the well.

The upper part of the wet contact block 8 is equipped with a contact group 10 and a docking unit 12 to provide mechanical and electrical connection and separation of the upper and lower parts of the wet contact to power an electric (or electromagnetic) valve 18.

Figure 3-7 shows the assembly processes of the layout, explaining the solution of the technical problem and the description of the method.

The run-down arrangement (Fig. 7) is an electric centrifugal pump 5 (or another type of pump) suspended on a tubing string, a submersible motor 6, as well as mechanically connected blocks of the upper 8 and lower 14 wet contacts. The lower wet contact block 14, as well as the eclectic valve 18, are located in the packer arrangement 17 with mechanical anchors 16 (Fig. 1). Anchors are designed to prevent axial displacement of the packer in case of high pressure drops over the packer and sub-packer zones.

In the case of descent of the packer equipment below the depth of descent of the pumping equipment, the upper wet contact block is mounted on the shank (pipe string or rods), which is directly fixed at the lower point of the electric motor of the electric centrifugal pump.

The control of the electrovalve 18 is carried out from the wellhead from the control station 1 by supplying power to the valve electric actuator.

In order to reduce the risk of locking the valve due to high back pressure in the sub-packer location of the electrovalve 18 is provided in such a way that the locking device is closed from top to bottom. Upon reaching the locking device of the valve seat 19, reliable formation isolation is achieved.

With the valve open, the flow of formation fluid through channels 15 in the packer arrangement is received at the pump intake and further at the wellhead.

Lowering of downhole equipment for ongoing underground well repair can be done in two ways.

The first method (Figure 3) involves the descent on the string of tubing 2 and a special disconnector 12 of the transport packer equipment 17 ′ with anchors 16 ′, comprising an electric or electromechanical valve 18 ′ in the closed state and the lower “wet” contact block .

The second method (Figure 4) involves the descent of the packer arrangement on the tubing string 2 together with the wet contact 8, 14, electrically and mechanically connected and disconnected by the unit. In this case, the geophysical cable 21 laid along the column can be fixed to the column with fastening belts 4. The cable is connected to the upper wet contact block through the cable geophysical tip 23. In this case, the packer assembly can be lowered with the electrovalve open 18. Dunn The second option, in addition to determining the tightness of the packer layout, will allow you to check the operability of the electrovalve, the reliability of the wet contact block connection.

The fluid flow in two ways occurs in the annular space between the packer layout and production casing.

Upon reaching the estimated deep descent (this may be the depth of the descent of the pump, the depth of the roof of the reservoir, etc.), the packer assembly 17 is planted, the pipe string is disconnected and lifted. The tightness check of the packer and valve assembly is carried out by crimping the production casing.

Next, the assembly is lowered from the submersible pumping equipment with the upper wet contact block 8 installed in the lower part (Fig. 6). After joining the upper and lower parts of the downhole electrically and mechanically connected and separable wet contact block, an electrical connection is established between the ground monitoring station 1 and the electrically or electromechanically controlled valve 18, as a result of which it becomes possible to control and measure the parameters of the well condition and cut off the flow of reservoir fluid with formation 20 in the case of preventive and repair work of pumping equipment.

If necessary, preventive and repair work of the pumping equipment (pump change), the pump is changed as follows.

On command from the mouth close valve 18 (Figure 4), as well as relieve pressure in the annulus. After that, the faceplate is disrupted, during which the wet and wet contact blocks 8 and 14 are mechanically disconnected. When lifting the submersible equipment, the volume of the extracted equipment is periodically replaced with water in order to maintain back pressure on the packer arrangement.

When replacing the pump with the pump being replaced, the upper wet contact block is installed. In order to prevent an impact on the lower part of the equipment, a guide funnel 11 and a locking device 13 are provided at a certain distance from the electrical contacts 10 in the lower wet contact block 14. When the stop element 9 of the upper wet contact 8 is reached, the weight of the entire column is unloaded, which will allow you to determine the position of the lower point of the draw and pick up fitting pipes for landing faceplates.

After assembling the fountain valves, at the command of the mouth, the electrovalve 18 is opened and the standard procedure for putting the well into operation is performed. When docking wet contact blocks, you can get information about the pressure in the sub-packer zone (downhole equipment may include the installation of sensors (pressure, temperature), as well as control the parameters of the well at the output.

The technological and economic effects of using the method of cutting off the reservoir for routine repairs without killing the well are achieved by preserving the productivity of the reservoir, reducing the cost of killing solutions and accelerating the maintenance and repair of pumping equipment.

Claims (1)

The method of cutting off the formation for underground repairs without killing the well using an electrically and mechanically controlled plug-and-play wet contact downhole block, including the descent and installation of a pipe string with a packer arrangement, blocks of sensors for monitoring the parameters of the reservoirs, controlled by electrical or electromechanical valves that control or cutting off the flow of fluid from the formations into the well, while the valves are controlled through the docked wet contact block, lin it is connected by a power cable of an electric motor of a submersible pump or an additional communication channel laid along a column, characterized in that a packer assembly containing a packer, an anchor, an electric or electromechanical valve blocking the passage channel in the packer, a sensor unit and a lower unit of a disconnected electric unit “Wet contact”, an electric submersible pump, to the lower part of which or to the shank with an emergency disconnecting device, the upper block of the disconnected electric wet contact block, connect the upper and lower wet contact blocks, open the electric or electromechanical valve by controlling through the wet contact block, operate the formation with a submersible pump until it becomes necessary to carry out underground repairs, after which the electric or of an electromechanical valve by means of control via a “wet contact” unit, an electric submersible pump, to the lower part of which or a shank with an emergency disconnect the device is fixed to the upper block of the wet contact disconnectable electric block, is removed from the well and underground repair is carried out, after which the operation of lowering the electric submersible pump is repeated.

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