RU2322570C2 - Oil production method and device - Google Patents

Abstract

FIELD: oil industry, particularly methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells.

SUBSTANCE: method involves installing downhole hydraulic piston motor of reciprocating type and downhole pump fixedly connected thereto in casing pipe by means of packer, wherein downhole pump is operated with the use of working fluid flow. Working fluid is circulated in closed loop to eliminate working fluid losses and to prevent mixing thereof with produced reservoir fluid. Reservoir fluid is supplied to well head through paired concentric flow string. Downhole hydraulic piston motor of reciprocating type is operated from well head. Device comprises downhole hydraulic piston motor of reciprocating type and downhole pump fixedly connected with each other and installed in casing pipe by means of packer. Downhole hydraulic piston motor and downhole pump are installed on paired concentric flow string having inner chamber isolated one from another with medium separation means. Hollow shaft passes through medium separation means. Hollow shaft communicates dowhhole pump with inner cavity of flow string having lesser diameter through inner channel. Downhole hydraulic piston motor of reciprocating type uses closed working fluid circulation loop to prevent working fluid mixing with produced reservoir fluid.

EFFECT: elimination of tubing string abrasion, simplified structure and decreased paraffin generation.

3 cl, 3 dwg

Description

The invention relates to the oil industry, and more specifically to methods of oil production.

A known method of oil production (RU 2065026 C1, IPC EV 43/00, 1996.08.10) using a deep pump. To prevent corrosion of the casing pipes by eliminating the contact of the surface of the casing pipes with the formation fluid, the downhole pump is installed above the reservoir, connected to the tail pipes. The tail pipes are lowered to the bottom of the well, and a check valve is placed at their lower end.

The disadvantages of this method of oil production is that this method, when used on low-yield wells, is used in conjunction with a sucker rod pump (SHG), which entails the abrasion of tubing, tubing breakage, high operating costs associated with replacement of tubing and rod string.

There is also a known method and device for oil production (RU 2088749, IPC ЕВВ 43/00, 1997.08.27), which includes a tubing string with a liner and a packer. A tubing pump is installed inside the tubing. A metering unit is placed in the tubing, which connects the tubing cavity to the annulus. The disadvantage of this method is that along with the supply of low-viscosity fluid into the annulus, formation fluid is selected using a sucker rod pump associated with a rocking machine, a string of pump rods, which complicates the design. Formation fluid is additionally diluted with the fluid supplied from the wellhead, which implies additional oil costs. The presence of a string of pump rods, the movement of which inside the tubing leads to wear of both the tubing and the string of pump rods itself, leads to an increase in operating costs.

There is also known a method of oil production using SHGN, based on the fact that the deep pump is driven by a rocking machine using a string of pump rods (see F. Gray. Oil production. - M., 2004).

The main disadvantages of this method of oil production is that during operation there is intense wear of the tubing due to abrasion by moving pump rods, wear and breakage of the pump rods themselves, which leads to production shutdown for changing pumping equipment and replacing the tubing string. In addition, an energy- and metal-intensive rocking machine is installed at the wellhead to drive the deep pump. All this leads to significant costs in oil production.

The closest technical solution is the principle of operation of the installation of hydraulic piston pumps (Oilfield equipment: Handbook. - M .: "Nedra", 1990, p.167-169). It is based on the use of hydraulic energy of a fluid pumped under high pressure into a hydraulic downhole reciprocating piston motor that converts this energy into the reciprocating motion of a piston pump rigidly connected to it. At the same time, a mixture of working fluid and formation fluid enters the mouth.

The disadvantage of this method is that in the process of oil production, the produced reservoir fluid is mixed with the working fluid, which entails the need for their separation and purification, and the mechanical impurities in the produced reservoir fluid impede the operation of the spool device that controls the operation of the hydraulic motor. The complexity of the design of the unit is due to the fact that the spool switching device is located inside the hydraulic actuator, and in case of failure it is necessary to raise the entire layout at the wellhead for repair. Since the working fluid is mixed with the produced formation fluid, there is a need for a large consumption of inhibitors that inhibit corrosion, and thereby increase operating costs. The objective of the invention is:

- improving the efficiency of work in oil production;

- elimination of wear of the tubing string due to its abrasion by sucker rods;

- simplification of the hydraulic drive design;

- the creation of conditions under which the control of the hydraulic drive is carried out only from the wellhead;

- ensuring the circulation of the working fluid in a closed cycle and eliminating the possibility of mixing it with the produced reservoir fluid;

- reducing corrosion of the tubing string and thereby increasing the overhaul period and lowering the cost of operating oil fields.

The problem is solved due to the fact that in the method of oil production, which consists in the fact that in the casing by means of a packer, a hydraulic downhole reciprocating piston engine and a deep-well pump rigidly connected to it are installed, which are controlled by the flow of working fluid, according to the invention, the supply of the working fluid is carried out in a closed cycle, eliminating its loss and mixing the working fluid with the produced formation fluid, which is fed to the mouth in a double, a concentrically arranged column of tubing, and the operation of the hydraulic downhole reciprocating reciprocating engine is produced from the wellhead.

The problem in the device that implements the method of oil production is solved due to the fact that in the device, which includes a deep pump and a hydraulic downhole reciprocating piston motor, rigidly interconnected and installed in the casing by means of a packer, according to the invention, the deep pump and the piston engine are mounted on a twin concentrically arranged tubing string, the internal cavities of which are isolated from each other by a medium separator, through The hollow rod passes through the internal channel and hydraulically connects the deep pump to the internal cavity of the tubing of a smaller diameter, and the hydraulic downhole reciprocating piston engine is arranged so that a closed cycle of the working fluid is used and its mixing with the produced reservoir fluid is excluded.

In the particular case of the device, the downhole pump comprises a suction valve in the lower part, and its cavity is divided by a piston equipped with a hollow rod with radial holes made above the piston and a discharge valve.

In addition, the hydraulic downhole reciprocating piston engine in the lower part contains one or more radial holes, and its cavity is divided by a piston equipped with a hollow stem with a valve.

Figure 1 shows a diagram of the implementation of the method of oil production; figure 2 - diagram of a device for oil production in the mode of absorption of reservoir fluid; figure 3 is a diagram of a device for oil production in the mode of injection of reservoir fluid.

Installation for implementing the method of oil production (Fig. 1) includes a pumping unit 1 with control systems located at the wellhead, a submersible pump 2, a hydraulic downhole reciprocating piston engine rigidly connected to it (hydraulic drive) 3. The whole assembly is lowered on a double, concentrically located tubing string 4 and 5 and is installed in the casing 6 by means of a packer 7.

Oil production is as follows.

The working fluid under pressure from the pump unit 1, located at the wellhead, is fed into the annulus 8 formed by the casing 6 and the tubing string 5, into the hydraulic actuator 3, which drives the depth pump 2, and the formation fluid is fed into the tubing string 4 and further on the wellhead. The working fluid, passing through the pump 3 drive through the annulus 9 formed by the tubing string 4 and the tubing string 5, is supplied to the pump unit 1.

The pump unit 1 is switched, and the supply of the working fluid is made into the annulus 9 and then into the hydraulic actuator 3, while the downhole pump 2 returns to its original state and receives a portion of the formation fluid inside.

Next, the cycle repeats.

As the working fluid, water with the addition of corrosion inhibitors or marketable oil can be used, and the reservoir fluid, for example, is a mixture of oil, produced water and associated gas.

The device for oil production contains a downhole pump 2, the piston 10 of which is rigidly connected to the piston 11 of the hydraulic actuator 3 through the hollow rod 12. In the lower part of the hollow rod 12 above the piston 10 there are one or more radial holes 13. A discharge valve 14 is arranged in the piston 10. the pump 2 in the lower part is equipped with a suction valve 15 and is connected in the upper part by means of a sub 16 with a hydraulic actuator 3. Inside the sub 16 there is a seal 17 for a hollow rod 12. The hydraulic actuator 3 in the lower part has one or more radial holes 18, providing hydraulic connection of the cavity 19 and the annular space 8 formed by the casing string 6 and the tubing string 5. The piston 11 is connected from above to the hollow rod 20, which through the valve 21 is hydraulically connected to the hollow rod 12 and the cavity 22 of the deep pump 2. Internal the channel 23 of the hollow rod 20 is hydraulically connected to the inner space 24 of the tubing string 4, which is separated from the annular space 9 by means of a medium separator 25, which can be an anchor shoe for the upper mechanical fastener Ia plug pumps RHAM such as "cone in cone" and the lock plug RHAM pumps with mechanical fastening of the upper API (catalog "sucker rod pumps" Izhneftemash, 1997, s.41-44 with. 57-64).

The tubing string 4 is installed inside the tubing string 5 through a centralizer 26.

The entire device for oil production is placed in the casing 6 using a hydromechanical or hydraulic packer 7.

A device for oil production works as follows.

Suction (figure 2)

The working fluid is pumped by the pump unit 1, located at the wellhead, into the annulus 8 and through the holes 18 enters the cavity 19 of the hydraulic actuator 3. The piston 11 and the piston 10 rigidly connected with it using the hollow rod 12 begin to move upward. In the cavity 27 of the submersible pump 2, a vacuum is created. The suction valve 15 opens and the cavity 27 is filled with fluid from the under-packer space 28. The pressure valve 14 is closed, the fluid located in the cavity 22 of the piston pump 2 through the radial holes 13 in the hollow rod 12, channel 29, open valve 21, channel 23 of the hollow rod 20 gets into the inner space 24 of the tubing string 4 and further at the wellhead. The working fluid located in the cavity 30 of the hydraulic actuator 3, through the annular space 9 enters the wellhead and then to the reception of the pump unit 1.

Injection (FIG. 3)

The pump unit 1, located at the wellhead, is switched over and the working fluid is supplied to the annulus 9, the pressure in the cavity 30 of the hydraulic actuator 3 rises, and the piston 11 starts to move downward, and the piston 10 of the submersible pump 2 rigidly connected with it via the hollow rod 12 The valve 21 closes, the discharge valve 14 opens and the fluid located in the cavity 27, through the radial holes 13 of the hollow rod 12 flows into the cavity 22 of the deep pump 2, filling it. The working fluid located in the cavity 19 of the hydraulic actuator 3, through the radial holes 18 flows into the annulus 8 and then at the wellhead to the intake of the pump unit.

Next, the cycle repeats.

The proposed technical solution allows you to completely eliminate the process of abrasion of the tubing and breakage of the pump rods due to their absence, significantly simplify the design of downhole equipment, which, in turn, will reduce the likelihood of failure, and thereby increase the mean time between failures, control the operation of the hydraulic drive from the wellhead . Since the working fluid is used in a closed cycle and does not mix with the reservoir fluid, corrosion inhibitors will be preserved, and thereby corrosion of the downhole equipment will be significantly reduced at no additional cost.

The presence of constantly circulating working fluid (warmed up if necessary) eliminates or reduces the paraffin formation process on the outer and inner surfaces of the tubing.

All this taken together allows you to significantly reduce both capital costs in the development of oil fields, and expenses during the operation of the fields.

Claims (3)

1. The method of oil production, which consists in the fact that in the casing by means of a packer a hydraulic downhole reciprocating reciprocating piston engine and a deep-well pump rigidly connected to it are installed, which are controlled by a working fluid flow, characterized in that the working fluid is supplied in a closed cycle, eliminating its loss and mixing of the working fluid with the produced formation fluid, which is fed to the mouth through a twin, concentrically located pump ompressornyh pipes, wherein operation control of hydraulic downhole motor piston reciprocating produce a wellhead. 2. Device for oil production, including a deep well pump and a hydraulic downhole reciprocating piston motor, rigidly interconnected and installed in the casing by means of a packer, characterized in that the deep pump and piston motor are mounted on a twin concentrically arranged pump string -compressor pipes, the internal cavities of which are isolated from each other by a medium separator, through which the hollow rod passes, through the internal channel hydraulically a unified deep-well pump with an internal cavity of a tubing of a smaller diameter, and a hydraulic downhole reciprocating reciprocating engine designed so that a closed cycle of the working fluid is used and its mixing with the produced reservoir fluid is excluded. 3. The device according to claim 2, characterized in that the submersible pump is equipped with a suction valve and a piston with a discharge valve and a hollow rod having radial holes in the lower part.

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