RU2394978C1 - Procedure for completion and operation of well - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: there is installed packer with by-pass facility underneath. Further, a deep-well pump is lowered on a flow string and well fluid is lifted via the flow string when the pump is alternately turned on and off. The by-pass facility is installed between the packer and the deep-well pump; the facility operates in "open" or "close" positions. When the by-pass facility is in the "close" position, the well is completed with the deep-well pump to a complete or partial replacement of water or sealing fluid under the packer. The deep-well pump is turned off; the by-pass facility is set from the position "close" to the "open" position; annular gas with reservoir fluid is bypassed through the facility via the flow string from under the packer space into cavity of the flow string; the well is put into flowing well operation. ^ EFFECT: raised efficiency of procedure for intensification of completion and operation of well with high gas factor, increased period of well flowing operation. ^ 9 cl, 2 dwg

Description

The invention relates to the oil and gas industry, in particular for the development and operation of production wells.

There is a method of simultaneous separate operation of two gas reservoirs, including separation of the reservoirs by a packer, gas extraction from the lower reservoir along the column of lifting pipes and gas extraction from the upper reservoir along the annulus, in which the annular over-packer space is purged periodically by blocking the column of lifting pipes with subsequent gas bypass from the column of lifting pipes to the annulus / SU 1406346 A1, IPC4 E21B 43/00, publ. 06/30/1988 /.

The disadvantage of this method is that its implementation requires periodic gas purging to remove fluid from the overpacker space, which is not always possible for geological and technological reasons to perform, in particular to remove fluid from the subpacker space of the well. In addition, this method generally does not provide for the exploitation by wells of oil and condensate deposits with a high gas factor, often more than 200-1000 m ³ / m ³ . The production of oil and condensate from these deposits is complicated due to the lack of in-depth pumping equipment that allows for long-term operation of wells with a very high gas factor, and flowing in them on a continuous basis does not occur due to the need to remove periodically accumulating water from the bottom of the well that drowns it.

There is a known gas-lift method for oil production in a well equipped with a packer and gas-lift valves, which control the pressure of the gas-liquid mixture, and after lowering and installing gas-lift valves in the well chambers, gas is injected into the annulus and the well development process starts / SU 1696676 A1, IPC5 E21B 34 / 06, publ. 12/07/91 /.

A disadvantage of the known method is that for its implementation, a forced supply of gas from the surface to the over-packer region is necessary for its passage through a valve located in the borehole chamber into the tubing to bubble fluid and facilitate the lifting of the gas-liquid mixture. It is not possible to supply gas from the wellhead under the packer.

The problem to which the claimed technical solution is directed is to develop a method for the continuous extraction of oil and condensate based on a combination and combination of the use of pumping and fountain production modes.

When implementing a technical solution, the task is solved by achieving a technical result, which consists in increasing the efficiency of well development and operation.

The specified technical result is achieved by the fact that in the method of development and operation of wells equipped with an in-depth pump and a packer, under which a bypass device is installed, configured to operate in the closed and / or open position, the downhole pump is lowered on the tubing and carry out the lifting of water and kill fluid through tubing by periodically turning on and off the downhole pump. The well is developed by a downhole pump until it is completely or partially replaced under the packer with water and kill fluid when the bypass device is in the closed position. The depth pump is turned off and the transfer device is switched from the “closed” position to the “open” position and annular gas is passed through the tubing from the subpacker into the tubing cavity together with the formation fluid and the well is brought to a fountain operation mode.

According to the claimed technical solution, it becomes possible to operate condensate and oil wells with a high gas factor of the reservoir by combining two operating modes: at the initial stage when starting and developing the well, it is supposed to be developed by a deep pump to extract the kill fluids, and then the subsequent transfer of the well to a fountain mode of operation , i.e. application of a combination of pumping and flowing production methods.

Killing fluids are divided into tenogenic killing fluids, such as fluids and killing fluids used in well repair, and natural killing fluids, such as saline and condensed wellbore water, which are part of the reservoir fluids. The formation fluid may consist of oil, condensate, gas, water and is multiphase.

The use of a submersible pump is short-lived. Its use is necessary for the extraction of kill fluids in order to bring the well to a fountain mode of operation after repair of cattle. Pumping out the kill fluids also causes a decrease in back pressure on the formation and, accordingly, creates conditions for its gushing.

During the well’s flowing operation, formation fluids with killing fluid and with a high water content (sometimes highly mineralized) are also suitable from time to time from the formation into the well, which, due to the insufficient speed of movement along the well’s lift, slowly settles along the tubing walls and accumulates on the bottom of the well, rising above the perforation interval. The accumulation of jamming fluid leads to a heavier column in the elevator of the well and subsequently to a complete cessation of flowing of the well.

To resume flowing, a downhole pump is periodically put into operation to extract the kill fluid that drowns out the flowing of the well. To do this, the bypass device is put into the “closed” state, for example, a blind plug or check valve is installed in the planting element or the hole in the regulator is remotely closed. The landing element is made, for example, in the form of a borehole chamber.

The bypass device is made in the form of a stationary or removable controller, as well as in the form of a valve or controller with remote electric or hydraulic control. After the transfer device is switched from the “open” state to the “closed” state, the pump is put into operation and the kill fluid is removed, which drowned out the fountain flow. Then the deep pump is stopped and the transfer device is switched from the “closed” state to the “open” state and the well is continued to be operated through the transfer device through the tubing string in the flowing mode.

The operation of the deep pump under the packer allows you to quickly work out and raise the killing fluid to the surface to reduce their negative impact on the well flowing. In this case, the submersible pump needs to work out only sub-packer kill fluid. The use of a packer that separates the annulus significantly reduces the volume of exhaust fluid killing due to the cutting and isolation of the overpack fluid killing.

The proposed method of well development and operation allows the additional use of free gas released into the free phase and accumulated in the sub-packer zone for transfer into the tubing inside to facilitate the produced formation fluid and enhance the process of its flowing. In addition, due to bubbling and lifting of the well fluid with gas, a low-density gas-liquid mixture is formed from the formation fluid, accompanied by a decrease in back pressure on the formation. This has a positive effect on the magnitude of the depression and, accordingly, on the inflow of formation fluid to the well, prolonging the flowing period.

Short-term operation of the downhole pump involves a forced selection mode, which leads to an additional decrease in the pressure on the formation to 0.7-0.8 of the saturation pressure, is also a positive factor. An increase in depression on the formation enhances the flow of formation fluid to the bottom of the well. In addition, lowering the pressure below the saturation pressure increases gas accumulation in the sub-packer region, which is used to enhance the effect of gas on bubbling and lifting of the well fluid in the tubing when opening the bypass device and bypassing the increased gas volume.

In contrast to the known solutions, instead of purging, a short-term operation of the deep pump is used to extract the kill fluid, and the gas evolved along with the product is passed through a bypass device into the tubing for bubbling and elevator lifting in order to intensify the transfer of the well to flowing production.

The invention is illustrated by drawings, which schematically shows a device for implementing the inventive method.

Figure 1 and figure 2 shows a well equipped with a downhole pump 1, for example, an electric centrifugal pump run on tubing 2 with cables 3, 4, a packer 5 and transfer devices, for example, in the form of an autonomous valve 6 in the well camera 7 and / or remotely controlled controller 8.

The method works as follows.

In the production casing 9 with a perforation interval 10, filled with a silencing liquid, a downhole pump 1 with a power cable 3 and, if necessary, umbilical 4, is lowered sequentially on a tubing string 2 to control a remotely controlled regulator 8.

Next, a borehole chamber 7 with a bypass device in the form of a check valve 6 or plug 11 and a regulator 8 in the packer is installed above the deep pump 1 under the packer 5, and then a packer 5 is installed in which the cables 3, 4 are sealed in a known manner, for example, according to patent No. 2305748.

The pump 1 is lowered to a predetermined depth, the packer 5 is packaged. A blind plug 11 is installed in the borehole chamber 7, and the bypass device, for example, in the form of a remote hydraulic regulator 8, is put into the “closed” state and the deep pump 1 is started up.

They begin to develop the well by working out the kill fluid. After working off and extracting the silencing fluid, the downhole pump 1 is turned off. The transfer device in the form of a regulator is turned into the “open” state, and using a wireline technique, the dead plug 11 is removed and the well is put into flowing operation partially in natural gas lift mode due to accumulated gas under the packer 5.

As gushing occurs, there is a gradual accumulation of kill fluid at the bottom, since condensate and oil from the reservoir always enter the well with a small percentage of water. The accumulation of water in the well as a kill fluid leads to a decrease in the flow rate of the well until it stops completely.

Then, after stopping the flowing of the well, the valve 6 is changed using a rope technique to a blank plug 11 and / or the regulator 8 is put into the “closed” state. If the bypass device is made in the form of a check valve 6 with the possibility of self-closing the passage hole at the time of starting the pump, then changing it to a plug is not required. The downhole pump 1 is launched into operation to lift the accumulated kill fluid in the form of water from the perforation interval 10 and from the bottom 12 of the well.

During the operation of the deep pump 1, the released gas accumulates under the packer 5. After the water has been drained from the bottom 12, the pump 1 is forcibly turned off or the pump 1 itself shuts off due to a supply interruption, for example, due to “underload” due to gas. Instead of the plug 11, a valve 6 is installed, for example, with the help of cable technology and / or with the help of the remote controller 8, it is put into the "open" state. Or, when the pressure of the sub-packer zone is higher than the pressure in the tubing, the check valve opens spontaneously, through the opening of which gas is released from the sub-packer zone into the tubing 2, causing the gas lift start and the well to flow into operation.

The downhole pump 1 may be equipped with a suction screen and / or filter to prevent mechanical impurities from entering the pump. In addition, additional equipment can be used, for example, clamps, centralizers and protectors for protecting and securing cables 3, 4, telescopic connections, disconnecting devices and technological well chambers to facilitate jamming and emergency operations.

In addition, to facilitate underground repairs, additionally, in the wells, a check or knock valve is installed above the packer in the tubing or in the well chamber with the aim of killing the well through it or eliminating ARPD, paraffin and hydrate plugs by various thermochemical leaching. This is necessary for the possibility of creating a circulation of the annular tube when killing the well before ORS or KRS or for hot flushing the well in case of contamination of the paraffin deposits (when needed).

To study the well, jet pumps and measuring instruments (cable or stand-alone) installed in the well chamber 7 or on the tubing 2 and on the centralizers can be used. Hose cable 4 or hydraulic tube may have an electrically conductive wire. The regulator 8 can be installed in the packer 5 or at a predetermined distance from the bottom of the packer 5. As valves, bellows regulators with a non-return valve can be used.

The downhole pump 1 can be a rod, centrifugal, multiphase, diaphragm, etc.

The downhole pump 1 is used mainly for well development and extraction of killing fluid. It is installed in the well in the absence of a sump in the perforation interval of 10 or above the perforation interval, and with a large sump and small values of mechanical impurities or in their absence, the pump is installed below the perforation interval 10, for example, at the bottom of the bottom 12 of the well. The technical characteristics of the deep pump 1 should ensure its high inter-period period (MCI). At the same time, the deep pump 1 is selected so that for a minimum time interval, for example, in an operating mode of 1-3 hours, the pump can fully master the well after repair work using killing fluids or stopping the flowing of the well and take away (raise to the surface) water and liquid jamming without overheating of a submersible motor.

Claims (9)

1. A method of developing and operating wells, including installing a packer, under which a bypass device is installed, lowering a downhole pump on tubing - tubing, lifting the wellbore fluid along the tubing by periodically turning the pump on and off, characterized in that between the packer and at least one bypass device and / or at least one landing element with a blind plug are installed by a depth pump, then when the bypass device is in the “closed” position, prevent the well from pumping up to fully or partially extract the water and the kill fluid, then turn off the downhole pump and transfer the transfer device from the closed position to the open position and / or change the blind plug to the transfer device and transfer it through the tubing from the subpacker annular gas into the pipe cavity together with the formation fluid and bring the well to a fountain mode of operation. 2. The method of development and operation of wells according to claim 1, characterized in that the bypass device is located in the packer and / or in the planting element, for example, in the form of a borehole chamber. 3. The method of development and operation of wells according to claim 1, characterized in that the bypass device is made in the form of a replaceable autonomous valve or a remotely controlled regulator. 4. The method of development and operation of wells according to claim 1, characterized in that the bypass device is remotely adjustable from hydraulic pressure or an electrical signal. 5. The method of development and operation of wells according to claim 1, characterized in that the transfer device is made in a fixed design in the form of an autonomous valve or a remote-controlled controller. 6. The method of developing and operating wells according to claim 1, characterized in that the downhole pump is run on the tubing in the perforation interval or lower in the sump. 7. The method of developing and operating wells according to claim 1, characterized in that the switching of the transfer device from the open and closed position is carried out electrically and / or hydraulically. 8. The method of development and operation of wells according to claim 1, characterized in that the development of the well by the pump and operation of the fountain through the bypass device periodically with a periodic change in the bypass device of the positions “closed” to “open” are periodically repeated. 9. The method of developing and operating wells according to claim 1, characterized in that a check and / or knock-off valve or a well chamber with a check valve is installed above the packer.

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