RU2814516C1 - Method and device for flushing well, treating formation and completing a well in one tripping operation - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: group of inventions is related to the oil industry and can be used in the development of oil fields. When implementing the method, a device is lowered onto a tubing string that destroys bottomhole cakes with a jetting effect, mechanical rotation or with a combined jetting effect with rotation, along with a liner made of tubing or drill pipes, an emergency disconnector, a device that distributes flows, including sealing elements cuff or cup type, moved along the production string in the activated state and a cross-sectional unit, a flushing device, including a movable rod and inlet circulation holes for supply and return of flushing fluid, a jet pump. The unit is configured to transfer the fluid flow supplied from the annulus above the sealing elements to the pipe space and back from the annulus below the sealing elements to the pipe space. The liquid is supplied into the annulus with its flow to the device that destroys the bottomhole cakes, with a combination of direct and reverse flushing, the ball is through which the rod is moved and the inlet circulation holes are closed for the supply and return of the flushing fluid is discharged, chemical reagents are pumped into the formation via the tubular space of the tubing. After the chemical reaction is carried out, the jet pump insert with fittings is released, the circulation holes of the jet pump are opened, liquid is supplied through the annulus and inflow from the well through the pipe space is caused.

EFFECT: time costs are reduced, the efficiency of technological work is increased, the number of tripping operations and the impact of killing fluids and flushing fluid on the formation are reduced, and the turnaround period is increased.

2 cl, 1 dwg

Description

A method and device for flushing a well, treating a formation and completing a well in one tripping operation.

Technical field

The group of inventions relates to the oil industry and can be used in the development of oil fields, in particular for carrying out well flushing operations, performing formation treatments under pressure and well development.

State of the art

Carrying out flushing of the well with subsequent treatment of the bottom-hole zone of the formation under pressure and with further development of the well can significantly reduce the number of tripping operations, significantly reducing the costs of well maintenance and increasing oil production.

The known method and device for flushing wells RU 2405914 C1, which is the closest method and is adopted as a prototype. A method of cleaning a well, which consists of lowering a liner with a device on a tubing string (tubing) or drill pipes (DP) and installing it at a given interval. At the lower end of the shank, a hydraulic jet nozzle or downhole motor is installed, and at the upper end - a washing device with drain holes and radial channels, including a movable hollow rod, a mechanism for switching the device to the working and transport position, a flow separator with inlet and outlet channels, and a sealing element ( GE). On the tubing or BT, the device is lowered into the well with open drain holes, placed at a level above the upper holes of the perforation interval of the upper (first) productive horizon or absorption (leaks) interval, at a distance not less than the distance from the jet nozzle or downhole motor to the artificial bottom of the well . Liquid is supplied into the device cavity through the tubing or BT, acting on a hollow movable rod with a ball valve, which, moving, closes the drain channels and compresses the GE through the pusher of the switching mechanism, closing the gap between the well wall and the device.

Then liquid is supplied into the annular space between the production string and the tubing or BT, which, through radial channels in the device body, acts on the internal cavity of the GE, providing a more reliable seal due to the difference in the flow area of the radial channels of the device and the outlet channels of the flow separator, then through the outlet channels and a liner with a jet nozzle or a downhole motor destroys and washes out sand plugs or other types of deposits, and carries slurry through the inlet channels of the flow separator along the internal channel of the device and tubing or BT to the surface, and the flow area of the output channels of the flow separator is less than the area of the flow separator cross sections of input channels. After the completion of the flushing operation by supplying liquid to the tubing or BT, the device is switched to the transport position, while the GE is unclenched, at the same time the channels for draining the liquid when lifting the device are opened, and the device is raised to the surface.

A device for flushing a well with drain and radial channels contains a movable hollow rod with a ball valve and a spring, a hollow cylindrical GE with profiled ends located on the outer side of the housing, a mechanism for switching the device to the working and transport position interacting with the rod, and a flow separator, which has input and output channels, with the input channels connecting the annular cavity under the device with the cavity of the movable hollow rod, and the output channels connecting the annular cavity above the device with the cavity of the shank with a jet nozzle or downhole motor. In the flow separator, the flow area of the output channels is less than the flow area of the radial channels in the device body and less than or equal to the flow area of the input channels. Due to the difference in the areas of the input and output channels, a working pressure difference is created across the internal cavity of the GE, which ensures more reliable sealing of the annular space above and below the GE when the device is operating in a well. The hollow rod is made movable, the upper collar of the rod is the seat of the ball valve, and a bushing is attached to it to block the drain channels of the device in the operating position. A spring rests against the bushing, providing reciprocating movement of the rod. There is a groove in the lower part of the rod that interacts with the mechanism for switching the device to the transport or working position. The switching mechanism consists of a pusher, a stopper, a latch, and a profile rotary sleeve. The upper end of the pusher interacts with the rotating profile bushing, and the lower profiled end is engaged with the GE using a collet. The upper end of the GE is movable, and the lower end is fixedly fixed using a mating profiled bushing with a collet hook to the device. The GE, through the pusher and switching mechanism, has the ability to be compressed in the working position and extended in the transport position.

This method does not allow subsequent treatment of the formation under pressure without transferring excess pressure to the production string above the device. At the same time, in the case of acid treatment of the formation, it is impossible to bring an aggressive acid composition to the formation without contact with the production string above or below the device. At the same time, this method and device do not allow the development of a reservoir under depression.

The invention SU1583593A1 E21B43/25 is known related to the oil and gas industry, namely to methods for processing the bottom-hole zone of heterogeneous formations. The purpose of the invention is to expand the functionality by providing simultaneous treatment of formations with various chemical reagents and increasing the efficiency of well flushing. Using tubing, the device is lowered into a well that exploits two productive intervals, one of which (upper) must be processed in order to intensify the flow of oil, the other (lower) - in order to isolate water inflows. The well is flushed by pumping flushing fluid into the annular space of the well with a pumping unit, while the liquid from the annular space enters through channels 6 into the body 1 of the device and then through channels 4 and jet nozzles 8 enters the wellbore below the sealing element, picks up sediment particles and through channels 1 and pipe 5 enter the tubing and are brought to the surface from the well. When flushing a well, the device is moved in the production casing by extending the tubing. After flushing the well, the injection of reagents intended for treatment begins. Initially, a reagent intended for treating the upper formation (acid solution) is pumped into the tubing and then a separating buffer with a volume greater than the internal volume of the device body, including the volume of pipe 5, and a reagent for treating the lower formation (viscoelastic composition based on polyacrylamide). Next, with the annular space open, reagents are pumped in such a way that the acid solution, having passed the pipe 5, enters the annular space of the well under the sealing element, then through the axial channels 4 enters the device body and, bypassing the radial channels 6, fills the annular space of the well above the sealing element . After this, the annular valve is closed and the reagents are forced into the productive formations by simultaneously pumping the displacement fluid into the tubing and the annular space by two pumping units. After allowing the reactants to react by pumping the flushing fluid into the annular space and moving the device in the production casing, the well is flushed from the reaction products of the acid solution with the formation rock and the remains of the viscoelastic composition in the wellbore.

This method does not allow subsequent treatment of the formation under pressure without transferring excess pressure to the production string above the device. At the same time, in the case of acid treatment of the formation, it is impossible to bring an aggressive acid composition to the formation without contact with the production string above or below the device. At the same time, this method and device do not allow the development of a reservoir under depression.

The technical problem to which the stated group of inventions is aimed is to reduce costs and increase the efficiency of technological work on the well, due to flushing using the combined effect of forward and reverse flushing, carrying out formation treatments under pressure, without the impact of excess pressure on the production string above device and subsequent development of a well under depression using a jet pump in one tripping operation (TLO). By reducing the number of tripping events, there is a reduction in the amount of time spent on well repairs, a decrease in the “harmful” impact of the kill fluid and flushing fluid on the formation, a reduction in the time it takes to bring the well into operation, and an increase in the turnaround period.

Revealing the essence

The technical result of the claimed group of inventions is to reduce costs and increase the efficiency of technological work on a well, reduce the number of tripping events, reduce the “harmful” impact of killing fluid and flushing fluid on the formation, reduce the time to bring the well to a certain operating mode, and increase the turnaround period.

The specified technical result is realized through the following techniques and design features of the device.

A method of carrying out well flushing, formation treatment and well development in one tripping operation, in which a device is lowered onto a tubing string that destroys bottomhole cakes with a jetting effect, mechanical rotation or a combined jetting effect with rotation. At the same time, a liner is lowered from the tubing or drill pipes, an emergency disconnector, a device that distributes flows, including sealing elements of the lip or cup type, moved along the production string in the activated state. And also a cross-sectional unit, configured to transfer the fluid flow supplied from the annulus above the sealing elements to the pipe space and back from the annulus below the sealing elements to the pipe space. In addition to the above, a flushing device is used, which includes a movable rod and inlet circulation holes for supply and return of flushing liquid, and a jet pump. In this case, liquid is supplied into the annulus with its flow to a device that destroys bottomhole cakes, with a combination of forward and reverse flushing, the ball is discharged, through which the rod is moved and the inlet circulation holes are closed for the supply and return of flushing fluid, chemical reagents are pumped into formation under pressure along the tubular space of the tubing, after a chemical reaction, the jet pump insert with fittings is released, opening the circulation holes of the jet pump, liquid is supplied through the annulus and causes inflow from the well through the tubular space.

A device for implementing a method for carrying out well flushing, formation treatment and well development in one tripping operation, having sealing elements of a lip or cup type installed on the device body, designed to hermetically separate the production string, and configured to move along the production string in an activated state without losing its tightness. In this case, the device contains a flow distribution unit, configured to redirect the flow from the annulus above the sealing elements into the pipe space under the device and back from the annulus below the sealing elements into the pipe space above the device. In addition, the device has inlet and outlet circulation holes; jet pump; a movable rod, made with the ability, after manipulation, to close the side circulation holes for supply and return of flushing liquid, while opening the flow of liquid up and down the central channel of the device.

The group of inventions is illustrated by drawings

Fig. 1 Diagram of the flushing device at the stages of flushing, processing the formation under pressure and developing a well under pressure in one trip (a - flushing stage, b - stage of processing the formation under pressure, c - development stage).

1 - Jet pump; 2 – inlet circulation hole of the jet pump; 3 – jet pump insert; 4 - a device that distributes flows with packing elements (lip or cup type) capable of moving along the production string in the activated state; 5 – inlet circulation hole of the flushing device for supplying flushing liquid; 6 - sealing elements; 7 – flushing device rod; 8 – unit that distributes the flow of the flushing device; 9 – inlet circulation hole of the flushing device for returning the flushing liquid.

Figure 2 Composition of the equipment layout for the method of flushing, processing the formation under pressure and completing a well under depression in one trip:

1 - Jet pump; 4 - Device that distributes flows with packing elements; 10 - Emergency disconnector; 11 – Liner of estimated length consisting of tubing pipes or drill pipes; 12 - A device that destroys bottomhole cakes with a hydromonitor effect, mechanical rotation or combined (hydromonic effect + rotation).

Carrying out the invention

A device is lowered onto the tubing string that destroys bottomhole cakes using a hydraulic jet effect, mechanical rotation, or a combination. In this case, a device is used to implement the method for carrying out well flushing, formation treatment and well development in one tripping operation, which has sealing elements of the cuff or cup type installed on the device body, configured to hermetically separate the production string, and configured to move along the production string in an activated state, without losing its tightness. In addition, the device contains a flow distribution unit configured to redirect the flow from the annulus above the sealing elements into the pipe space under the device and back from the annulus below the sealing elements into the pipe space above the device. In addition, the device has inlet and outlet circulation holes; jet pump; a movable rod, made with the ability, after manipulation, to close the side circulation holes for supply and return of flushing liquid, while opening the flow of liquid up and down the central channel of the device. The hydraulic monitor effect of the device is ensured by blocking the large passage channel and directing the flow through a narrowing hole when unloading the device onto the bottom-hole cake with a certain force, pre-set before the work. In this case, in the process of unloading the weight of the tubing onto the equipment and switching to the hydraulic monitor mode, the tip with specially sharpened knives rotates, which additionally destroys the bottomhole cake by mechanical rotation. A liner consisting of tubing pipes or drill pipes is lowered. Then the emergency disconnect switch is lowered. A device is lowered that distributes flows and includes sealing elements of the cuff or cup type, designed in such a way that it is capable of moving along the production string in the activated state and hermetically separates the annulus space above and below the device. In this case, the device has in its design a cross-section unit that allows the fluid flow supplied from the annulus above the sealing elements to the pipe space under the device and back from the annulus below the sealing elements to the pipe space above the device. At the same time, the device allows you to close the side holes and open a direct passage in the central channel, allowing fluid to flow in both directions. A jet pump is lowered, capable of, after dropping the insert with fittings, opening the circulation hole and causing inflow from the well through the pipe space, using the created ejection effect, when supplying liquid through the annulus.

At the same time, at the stage of lowering the assembly and flushing the well, the inlet circulation holes of the flushing device for supplying and returning flushing fluid are in the open state. The inlet circulation hole of the jet pump is in a closed state. Flushing is carried out by supplying liquid into the annulus. Through hole 5 and the unit that distributes the flows, the flushing fluid enters the internal cavity of the tubing under the flushing device and subsequently enters the lower equipment - a device that destroys bottomhole cakes with a jetting effect, mechanical rotation, or a combined jetting effect with rotation. After the crust is destroyed, the flushing liquid, together with suspended particles from the destroyed crust, rises through the annulus along the liner to the flushing device and through the inlet circulation hole of the flushing device enters the tubing and is carried to the surface. The combination of reverse and forward flushing due to the redistribution of flows in the flushing device makes it possible to destroy cakes with greater efficiency, since liquid from a larger volume of the annulus enters the tubing space, thereby increasing the flow rate for destruction of the cake. The reverse flow from a large volume of the annulus entering the tubing space allows suspended particles to be carried to the surface at a higher speed. The device moves down the string by extending tubing pipes. After each increase, it is necessary to replace the calculated volume of liquid for the complete release of suspended particles to the surface. The extension of the tubing and flushing of the bottom of the well is repeated until the target bottom of the well is reached. At the stage of processing the formation under pressure, the ball is released, through which the rod of the flushing device moves and the inlet circulation holes of the flushing device are closed for supply and return of flushing fluid. After which it becomes possible to pump chemical reagents into the formation under pressure through the tubing space. Bringing the chemical reagent into circulation is ensured by the estimated time for releasing the ball and supplying the reagent. After the chemical reaction, the jet pump insert is reset. During the mastering phase, the jet pump insert opens the inlet circulation port of the jet pump. After which, by supplying liquid through the annulus, the well is developed using a jet pump. The use of deep autonomous pressure gauges in the layout will allow geophysical research based on the pressure recovery curve.

Thus, the proposed inventions solve the problem of reducing the amount of time spent on well repairs, reducing the “harmful” impact of kill fluid and flushing fluid on the formation, reducing the time to bring the well into operation, increasing the turnaround period by reducing the number of trips to clean the well and treat the formation and well development in one tripping operation.

Claims (2)

1. A method of carrying out well flushing, formation treatment and well development in one tripping operation, in which a device is lowered onto a tubing string that destroys bottomhole cakes with a jetting effect, mechanical rotation or a combined jetting effect with rotation, a liner made of tubing or drill pipes, an emergency disconnector, a device that distributes flows, including sealing elements of the lip or cup type, moved along the production string in the activated state, and a cross-sectional unit configured to transfer the fluid flow supplied from the annulus above the sealing elements into the pipe space and back from the annulus below the sealing elements into the pipe space, a flushing device, including a movable rod and inlet circulation holes for supply and return of flushing fluid, a jet pump, supplies liquid into the annulus with its flow to the device that destroys bottomhole cakes, with a combination of direct and reverse flushing, the ball is reset, through which the rod is moved and the inlet circulation holes for the supply and return of the flushing fluid are closed, chemical reagents are pumped into the formation under pressure through the tubing space, after the chemical reaction the jet pump insert is reset with fittings that open the circulation holes of the jet pump, supply liquid through the annulus and cause inflow from the well through the pipe space. 2. A device for carrying out well flushing, formation treatment and well development in one tripping operation, having sealing elements of the cuff or cup type installed on the device body, designed to hermetically separate the production string, and configured to move along the production string in activated state, without losing tightness; a flow distributing unit configured to redirect the flow from the annulus above the sealing elements into the pipe space under the device and back from the annulus below the sealing elements into the pipe space above the device, inlet and outlet circulation holes, a jet pump, a movable rod configured to after manipulations, close the side circulation holes for the supply and return of the flushing liquid, while opening the flow of liquid up and down the central channel of the device.