RU2737805C1 - Production method of oil with high gas factor - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, for development and operation of production wells on oil fields with high gas factor. According to the method, the packer is lowered to the vertical borehole and the packer is installed above the productive formation. Pump is lowered on pipe string with inlet located above packer with communicated parallel connection pipe. Outlet of branch pipe is located above pump inlet, and inlet is interconnected with sub-packer space of well. Degassed production of the formation is selected by the pump by the pipe string, and the gas - from the annular space. At the same time geophysical investigations are used to determine saturation pressure of formation product, as well as critical pressure of formation, at which formation reservoir properties are disturbed, and corresponding liquid levels. Before lowering, packer is rigidly connected to hollow branch pipe, which is connected to pump string by communicator made in form of parallel armature. This is done so that outlet of branch pipe after descent on pipe string and installation of packer is located above critical level, but lower than that of saturation pressure level. During descent the pump inlet is located below the critical level. Fluid level in well is controlled by pressure sensors or wellhead level meter, technologically connected to pump control unit. Pump operation is controlled by means of this unit to ensure fluid level in space above packer between pump inlet level and saturation pressure level.

EFFECT: higher efficiency.

4 cl, 1 dwg

Description

The invention relates to the oil and gas industry, in particular for the development and operation of production wells in oil fields with a high gas ratio.

The known method of development and operation of wells (patent RU No. 2394978, IPC Е21В 43/00, publ. 20.07.2010 Bull. No. 20), including the installation of a packer, under which a bypass device is installed, lowering a deep pump on tubing - tubing, lifting the well fluid along the tubing by periodically turning on and off the pump, and between the packer and the deep pump is installed at least one bypass device and / or at least one landing element with a blind plug, then when the bypass device is in in the "closed" position, the well is developed with a pump until the complete or partial extraction of water and kill fluid, then the submersible pump is turned off and the bypass device is moved from the "closed" position to the "open" position and / or the blind plug is changed to the bypass device and passed through it along the tubing from the subpacker, annular gas into the tubular cavity together with the formation fluid and bring the well to fountain mode of operation.

The disadvantages of this method are the complexity of implementation due to the need for constant monitoring of the dynamic level of the liquid, the need for constant synchronous switching on / off of the pump and the closing and opening of the bypass valve, which reduces the reliability directly related to the number of transient processes during switching.

There is also known a method of pumping oil with a high gas-oil ratio (patent RU No. 2627797, IPC Е21В 43/00, publ. 08/11/2017 Bull. No. 23), including drilling a sidetrack below the dynamic fluid level in the main wellbore, cementing the bottom of the main wellbore and lowering equipment into it, moreover, a liner is lowered into the main bore below the sidetrack inset, the deep pump is positioned above the sidetrack inset, the annular space of the well is connected to the upper part of the pressure tank and a discharge manifold located at the wellhead, and the lower part of the pressure vessel is connected with a pump, the receiving part of which communicates with the supply tank for the working fluid, and the pumping out of the accumulating gas from the annular space is performed periodically using a pump that is switched on to supply the working fluid to the injection tank with gas in the cycle of its injection into the flow manifold, and is disconnected to drain the working liquid from the injection tank to the supply tank in cycle le the gas flow from the annular space into the injection tank.

The disadvantages of this method are the complexity of implementation, high material costs associated with the construction of a sidetrack, and the impossibility of operation with a decrease in reservoir pressure below the tie-in (taking into account that the tie-in angle is 2º - 4º, and the minimum radius of curvature is about 60 m, the tie-in should to be carried out above the top of the productive formation at least 40 m, that is, the operable reservoir pressure limit should be at least ≈ 0.4 MPa, and taking into account the decrease in the hydrodynamic level by the pump - 0.5 - 0.6 MPa, in order to exclude the stall of the fluid flow by pump inlet).

The closest in technical essence is a downhole pumping unit (patent RU No. 2586349, IPC Е21В 43/00, Е21В 43/38, publ. 10.06.2016 Bull. No. 16), including a sucker rod pump, a liner pipe with a check valve installed on the packer, moreover, that the switch, mounted on the stops of the liner pipe, hydraulically connects the said liner pipe through the check valve installed at its upper end with the candle pipe, the length of which exceeds the distance from the dynamic level to the pump suspension depth, while the pipe - a liner with a pipe-candle form a hydraulic channel for communication of the bottomhole with the annular space, parallel to the pipe-candle, a sucker rod pump is installed on the upper coupling half of the said switch, while the lower end of the switch is made in the form of a truncated cone with a base directed downwards, and is equipped with centralizers.

This device implements a method of oil production with a high gas-oil ratio, including running on process pipes into a vertical well and installing a packer with a liner pipe equipped above the packer with a check valve and external stops, removing process pipes, running on a pipe string with a communicator pump, bottom end which is made in the form of a truncated cone with a base directed downwards, and is equipped with centralizers along the outer diameter, with a pipe-candle parallel to the pump connected to the inner cavity of the communicator, the communicator is lowered before installing the communicator using a cone on the outer stops of the pipe-liner with the location of the upper edge the pipe-candles (branch pipe) are higher than the dynamic level formed during the operation of the pump, while the liner pipe with the pipe-candle form a hydraulic channel for communication of the well bottom with the annular space, and the pump inlet is located above the communicator.

The disadvantages of this method are a narrow area of application due to the possibility of practical implementation of the method in the pressure range from 0.3 MPa to 10 MPa, which is due to the presence of a communicator located above the packer, a check valve (to open which requires at least 0.1 MPa) in a liner pipe located below the packer, under which, because of this, the gas released from the product accumulates (which, being a natural damper for pumping above the packer, requires at least 0.1 MPa) plus at least 10 m above the level of paste for installing the packer, and the need to position the pipe-candle above the dynamic level, which at a level of 1000 m (approximately 10 MPa) above the packer level can in a high degree of probability lead to a break in the tubing string or disruption of the connection with the communicator, also due to the presence of a check valve in the liner and under-packer space is impossible carry out any theological operations, while the complexity of implementation, since installation requires a at least two tripping operations (setting a packer and lowering pumping equipment with a pipe-plug) and a high probability of disruption of the reservoir properties of the formation due to the complete lack of protection from it.

The technical objective of the proposed invention is to create a method of oil production with a high gas-oil ratio, which makes it possible to simplify and reduce material costs due to the reduction of tripping operations when installing equipment to one, to protect the formation from the effects of destructive low pressures and to expand the field of application due to the possibility of exploiting productive formations with minimum reservoir pressure ≈ 0.1 MPa and the possibility of carrying out technological operations in the under-packer space of the well.

The technical problem is solved by the method of oil production with a high gas-oil ratio, including running into a vertical wellbore and installing a packer above the pay zone, running a pump on a pipe string with an inlet located above the packer with a parallel pipe connected by a communicator, the outlet of which is located above the pump inlet, and the inlet communicated with the under-packer space of the well, extraction of degassed formation products by a pump along the pipe string, and gas from the annulus. The authors do not pretend to this.

What is new is that preliminary geophysical studies determine the saturation pressure of the formation production, the critical formation pressure at which the reservoir properties of the formation are disturbed, and the corresponding fluid levels, the packer is rigidly connected before running into a branch pipe, which is connected to the pump pipe string by a communicator made in in the form of a parallel anchor, so that after running on the pipe string and installing the packer, the outlet of the branch pipe is located above the critical level, but below the saturation pressure level; during the descent, the pump inlet is located below the critical level, while the liquid level in the well is monitored by pressure sensors or a wellhead level gauge , technologically connected with the pump control unit, which regulates its operation to find the liquid level in the above-packer space between the pump inlet level and the gas production level.

It is also new that for carrying out technological operations, a technological string is introduced into the sub-packer space of the well through a branch pipe.

It is also new that within the range from the pump level to the saturation pressure level, the technologically justified minimum and maximum levels, respectively, are selected, the liquid level is controlled by turning the pump on and off, and when the liquid level in the above-packer space drops to the minimum operating level, it is turned off, and when recovering to the maximum operating level - turn on.

It is also new that within the range from the pump level to the saturation pressure level, the technologically justified minimum and maximum levels, respectively, are selected, within which the pump performance is smoothly controlled.

The drawing shows a diagram of the implementation of the method in longitudinal section. Structural elements, process connections and seals that do not affect the performance of the method are not shown in the drawing or are shown conditionally.

The method of producing oil with a high gas-oil ratio is carried out in the following sequence.

Preliminary geophysical studies in well 1 determine the saturation pressure, below which there is intense gas release from the production of formation 2, the critical pressure of formation 2, at which the reservoir properties of formation 3 are disturbed, and the corresponding liquid levels 3 and 4 (shown conditionally), calculated by formula:

H = P / (g × ρ) ,

where H is the liquid level above the productive layer 2, m;

g - acceleration due to gravity, ≈ 9.81 m / s ² ;

ρ is the density of the produced formation fluid, kg / m ³ .

Then a packer 5 (for example, protected by patents RU No. 47047, 59127, 77338 or the like) is installed above the opened layer 2 with a branch pipe 6 communicating the upper part of the under-packer space 7 of well 1 with the over-packer space 8 at a level above the critical level 4 , but below the saturation pressure level 3 (in practice, for maximum gas separation efficiency: above the critical level 4 by 0.15 - 1.5 m). This installation of the branch pipe 6 completely excludes the impact on the formation 2 by pressures below critical, excluding emergency situations.

To accelerate the release of gas (gas separation) from the formation product, the top of the nozzle 6 can be equipped with a helicoidal nozzle 9 to accelerate and / or swirl the flow. If it is necessary to carry out technological operations in the sub-packer space 7, a bell 10 can be installed on top of the branch pipe for receiving and guiding the technological pipe (for example, a coiled tubing pipe, a hollow sucker rod, or the like - not shown) with technological equipment (not shown). Since such technical solutions are known, the authors do not pretend to them.

On the pipe string 11, pump 12 (sucker rod pump - sucker rod pump, electric centrifugal pump - ESP or the like) is lowered into the vertical wellbore 1, the outlet 13 of which is located above the packer 5, but below the critical level. To control the liquid level, the pump 12 before running can be equipped with pressure sensors 14 with a cable 15 or the well with a wellhead level gauge (ultrasonic, laser, or the like - not shown), technologically connected with a control unit (not shown) of the pump 12, which regulates its operation to find liquid level 16 (dynamic level) in the above-packer space 7 during production of formation 2 between the level of inlet 13 of pump 12 and the saturation pressure level 3. To run packer 5 and pump 12 in one running operation, branch pipe 6 and pipe string 11 are connected by a communicator - a parallel anchor 17 so that the inlet 13 of the pump 12 and the upper edge of the branch pipe 6 with the packer 5 are at the required distance to ensure the above specified conditions for their installation in the well 1. The entire assembled structure on the pipe string 11 is lowered into the well 1, and the packer 5 is installed above the productive formation 2 before starting the pumps 12.

Pump 12 is started to take out degassed product from formation 2 through pipe string 11, and gas is taken from the annulus of pipe string 11 at the wellhead 1 (not shown). The authors do not pretend to take gas from the annulus of well 1, since the devices and methods for such sampling are known.

Adjustment of the liquid level 16 in the overpacker space 7 can be carried out in two ways.

Option 1

When using an unregulated pump 12, the liquid level 16 in the above-packer space 8, which is determined by the readings of the sensors 14 or the wellhead level gauge transmitting a signal to the control unit, is controlled by switching on and off. To do this, select technologically justified, respectively, the minimum and maximum levels (not shown - the working interval) between the levels of the inlet 13 of the pump 12 and the saturation pressure 3. When the liquid level 16 in the above-packer space 8 drops to the level of the minimum level of the working interval at the signal of the control unit, the pump 12 is turn off, and when restored to the maximum level of the operating interval, turn it on.

Option 2

When using variable drives of pumps 12 (for sucker rod pumps - wellhead, for ESP - submersible electric motor - not shown) the liquid level 16 in the above-packer space 8, which is determined by the readings of sensors 14 or a wellhead level gauge that transmits a signal to the control unit, is maintained constantly by adjusting the drive pump 12. When the liquid level 16 in the above-packer space 8 drops to the minimum level of the working interval, it sends a signal to the variable pump drive 12 to increase the pump 12 performance (for sucker rod pumps - an increase in the reciprocating speed, for an ESP - an increase in the speed of the submersible electric motor - SEM) , and when the liquid level 16 in the above-packer space 8 rises to the maximum level of the working interval, the control unit sends a signal to the variable drive of the pump 12 to reduce the performance of the pump 12 (for sucker rod pumps - a decrease in the speed of the reciprocating motion, for an ESP - a decrease in the motor speed) ... The regulation of the pump 12 capacity continues until the liquid level 16 is established within the operating range.

The working interval of the liquid level 16 in the above-packer space 8 is determined based on one of the criteria or their combination in various variations, for example: the operating mode of the pump 12 (determined by the passport data); the maximum possible profitability (the ratio of produced oil to material costs, for example, electricity); operating mode of the pump drive 12 (determined by the drive's passport data) and / or the like.

If it is necessary to carry out, without removing the pump 12 from well 1 (which is temporarily stopped), technological operations in the under-packer space 7 (for example, treatment of the bottomhole zone (BHZ) of formation 2 with acid, reagents for dissolving asphalt-resin-paraffin deposits (ARPO), and / or the like. ), a process string is lowered into the well (coiled tubing, hollow rods, etc. - not shown), with the help of a socket 10 through a pipe 6, they enter the sub-packer space 7, where the necessary technological operations are carried out by pumping reagents to enhance the production of reservoir 2 or cleaning the bottomhole zone of the formation 2. After technological operations, the process pipes are removed from the well 1 and the pump 12 is restored.

Start work after lowering the pump 12 as follows.

The pump 12 is put into operation, which reduces the liquid level 16 in the above-packer space 8 below the reservoir one for the production of the formation 2 from the sub-packer space 7 through the branch pipe 6 under the action of the reservoir pressure. After that, by withdrawing the product from the pump 12, the liquid level 16 is reduced below the maximum level of the working interval for intensive gas release from the product of formation 2 entering the above-packer space 8 due to a decrease in pressure. If necessary, to accelerate gas evolution, the product is accelerated and / or twisted in a helicoidal pipe 9, which provides an additional decrease in hydrostatic pressure in the flow of formation 2. The released gas rises through the annulus of the pipe string 11 to the wellhead 1, from where it is taken, and degassed product flows from of the branch pipe 6 down the above-packer space 8 to the packer 5, from where it is taken by the pump 12 and rises to the surface along the pipe string 11. After starting the pump 12 into operation, the control is carried out using a sensor 14 or a wellhead level gauge and a control unit for adjusting the operating modes of the pump 12. For the installation of the packer 5 and the start-up of the pump 12 is sufficient for the height of the liquid column above the formation 2 of about 10 m, which approximately corresponds to a pressure of 0.1 MPa.

The applied method of oil production with a high gas-oil ratio makes it possible to simplify and reduce material costs due to the reduction of tripping operations when installing equipment to one, to protect the formation from the effects of destructive low pressures and to expand the field of application due to the possibility of operating productive formations with a minimum formation pressure of ≈ 0 , 1 MPa and the possibility of carrying out technological operations in the sub-packer space of the well.

Claims (4)

1. A method of oil production with a high gas-oil ratio, including lowering into a vertical wellbore and installing a packer above the pay zone, lowering a pump on the pipe string with an inlet located above the packer with a parallel pipe connected to a communicator, the outlet of which is located above the pump inlet, and the inlet is communicated with the under-packer space of the well, extraction of degassed formation products by a pump along the pipe string, and gas from the annular space, characterized in that preliminary geophysical studies determine the saturation pressure of the formation product, the critical formation pressure at which the reservoir properties of the formation are disturbed, and the corresponding levels liquid, the packer before running is rigidly connected to a hollow pipe, which is connected to the pump pipe string by a communicator made in the form of a parallel anchor, so that after running on the pipe string and installing the packer, the outlet of the pipe is located above the critical level, but below the pressure level n saturation, during descent, the pump inlet is located below the critical level, while the liquid level in the well is controlled by pressure sensors or a wellhead level gauge, technologically connected to the pump control unit, with the help of which its operation is regulated to find the liquid level in the above-packer space between the pump inlet level and the level saturation pressure. 2. The method of oil production with a high gas-oil ratio according to claim 1, characterized in that a production string is introduced into the sub-packer space of the well through a branch pipe to carry out technological operations. 3. Method of oil production with high gas-oil ratio according to one of paragraphs. 1 or 2, characterized in that, within the range from the pump level to the saturation pressure level, the technologically justified minimum and maximum levels, respectively, are selected, the liquid level is controlled by turning the pump on and off, and when the liquid level in the above-packer space drops to the minimum operating level, it is turned off , and when restored to the maximum operating level, they turn on. 4. The method of oil production with a high gas factor according to one of paragraphs. 1 or 2, characterized in that, within the range from the pump level to the saturation pressure level, the technologically justified minimum and maximum levels, respectively, are selected, within which the pump performance is smoothly controlled.

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