RU2359114C2 - Method and facility for simultaneous selective treatment of perforation channels and treatment of bottomhole of conditionally endless thickness layer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention group relates to field of oil and gas industry and can be used for selective treatment of perforation channels and treatment of bottomhole of layer. Treatment method of perforation channels and treatment of bottomhole includes lowering of movable on pump-compressor pipe (PCP) of facility elements for treatment of perforation channels and treatment of bottomhole, implemented in the form of stator and rotor with channels, pumping the working substance under pressure through the facility. Facility is outfitted by body in the form of section of perforated casing string. Stator is implemented in the form of holed washer, located on-the-mitre to the plane of rotor impeller, outfitted by element, encapsulating space between the stator and facility body. On the outside surface of PCP it is rigidly fixed nipple element and stator. Rotor is located between stator and nipple element and it is implemented in concert with impeller. Lifting-lowering of the facility elements, fixed on outside surface of PCP is implemented by elevator from the surface in the range of the facility body.

EFFECT: treatment of perforation channels and treatment of bottomhole without restrictions simultaneously to treated thickness of perforation interval.

6 cl, 3 dwg, 1 ex

Description

The invention relates to the field of oil and gas industry and can be used for selective cleaning of perforation channels and treatment of the bottom-hole formation zone (PZP) of any thickness.

Known technical solutions regarding vibrators-generators of elastic waves using an impeller / for example, patent No. 2157452, ЕВВ 43/25, publ. 10/10/2000; utility model patent No. 11262, ЕВВ 43/25, publ. 09/16/1999 /. Their disadvantage is that the pulsating flow of the working agent directedly affects the fluid inside the casing of the well, and the impact outside the casing is limited. Processing a layer of significant thickness increases the processing time by several times and is associated with additional technological manipulations. Also, the use of a working agent is of a one-time nature and, accordingly, uneconomical.

Known hydraulic spool vibrator (GVZ), designed to process the bottom-hole zone (SCR). The device includes a barrel rigidly fixed on a tubing (tubing), having the form of a glass with slotted slots on its generatrix. A spool freely rotates on the trunk, which also has slotted slots along its generatrix and is somewhat similar to an impeller, since the slots in the trunk and in the spool are made at some angle to the generatrix; moreover, on the spool, the slots are made in the opposite direction to the slots in the barrel. In addition to slotted slots, there are launching holes in the barrel that allow the spool to start when the slots in the barrel are closed. These elements are placed in a protective housing / S.M. Gadiev. The use of vibration in oil production. - M: Nedra, 1977, p. 49 /.

The fluid passes through the holes in the barrel and enters the holes in the spool. Since these holes are angled, the spool starts to rotate due to the reaction of the jet. While rotating, it periodically blocks the holes in the barrel, as a result of which a hydraulic shock occurs, directed (unlike the indicated analogues) to the walls of the perforated casing string.

The disadvantages of this technical solution include insufficient efficiency and reliability, including due to the low starting torque and the high probability of jamming of the spherical ball bearings, even with minor mechanical impurities in the working fluid. In addition, a direct hydraulic shock is formed in the internal cavity of the barrel and tubing, which adversely affects the tightness of threaded joints and the integrity of the apparatus structure. The impact on the PPP is due to reverse water hammer, which is formed in the annular space between the apparatus and the casing and has a multiple of a smaller amplitude relative to the direct water hammer.

GVZ allows reverse hydroblows to destroy solid deposits in the perforation and PZP channels without their removal into the wellbore. Partial removal is possible only if the reservoir pressure exceeds the bottomhole pressure. Otherwise, the destroyed solid deposits move deep into the bottomhole zone, worsening its reservoir properties.

The use of a gas-liquid mixture (GHS) as a working agent is ineffective.

The prototypes of the proposed method and device are, respectively, the method and the device that implements it for exposure to the bottomhole formation zone of a well and its cleaning / Patent No. 20128, ЕВВ 37/08, publ. 10.20.2001 /.

The prototype device includes a shank, a check valve, an implosion device and a tubing, which are installed in series and connected by pipes, and it is equipped with a hydraulic spool type decalator installed between the check valve and the implosion device, which is made with a check valve. The device can be equipped with a jet pump mounted on the tubing in such a way that its inlet openings are blocked by a through plug installed in the tubing, and the outlet nozzle is in communication with the space of the well, and the through plug is installed with the possibility of removing and installing a blind plug between the inlet in the tubing jet pump and check valve between the jet pump and the plunger. The device may be provided with a packer installed between the hydraulic decalator and the implosion device. The hydraulic decalator can be made with a spool device, including a cylinder with holes in the form of a stator and a rotating spool in the form of a rotor with tangential slots.

The main disadvantage of the prototype method and the prototype device is that they do not clean the perforation channels selectively. All elements of the device are included in the tubing string only for delivery, installation and preparation for periodic operation, in contrast to the inventive device, which operates continuously with continuous tubing movement, regardless of whether the working agent is pumped. Accordingly, the prototype device clears the PZP periodically and periodically, and the claimed - continuously and all intervals at the same time. The layout of the prototype device does not allow the use of a working agent repeatedly until it is completely decontaminated; does not allow working on GHS due to the spool decalator, which works only on incompressible media; does not allow to process simultaneously several perforation intervals. The jet pump is inefficient.

The problem and the expected technical result consists in the development of a method and device for cleaning the perforation channels and processing the bottomhole zone without limiting the simultaneously processed thickness of the perforation interval. The reuse of the working agent is ensured, if necessary, until it is completely decontaminated. The ploying nature of the device provides, when moving up and down, the excitation of low-frequency disturbances in the processed interval (plunger effect), which provides an impact on the remote zones of the bottom-hole zone.

The problem is solved in that the method of cleaning the perforation channels and processing the bottom-hole zone, including the descent of the elements of the device for cleaning the perforation channels and processing the bottom-hole zone, made in the form of a stator and rotor with channels, pumping a working agent under pressure through the device, characterized in that the device is provided with a housing in the form of a section of a perforated casing string, and the stator is made in the form of a washer with holes located at an angle to the plane the speed of the rotor impeller, equipped with an element that seals the space between the stator and the device body, the fitting element and the stator are rigidly fixed on the outer surface of the tubing, the rotor is placed between the stator and the connecting element and integral with the impeller, lifting and lowering the device elements fixed on the outer surface of the tubing carry out a hoist from the surface within the device.

Pumping of the working agent under pressure through the device is carried out until the case is filled with it, after which pumping is stopped without stopping the lifting and lowering of the device elements that are transported to the tubing by the elevator from the surface by means of the tubing within the device body. The ascent-descent of the device elements to be moved to the tubing by the elevator continues until the decontamination or production of the volume of the working agent. After deactivation or development of the volume of the working agent, pumping of a new portion of the working agent is additionally resumed or another working agent is pumped. The outer surface of the tubing is provided with several elements of several devices that are lowered simultaneously.

The problem is also solved in that the device for cleaning the perforation channels and processing the bottomhole zone, including a stator rigidly fixed to the tubing with holes, a rotor with channels, differs in that the stator holes are made at an angle to the plane of the rotor impeller, the stator is a washer fixed on the outer surface of the tubing, equipped with an element that seals the space between the stator and the housing; the device is additionally equipped with a fitting element rigidly fixed to the outer surface of the tubing; the rotor is located between the stator and the fitting element and is made integral with the impeller, and it is possible to move the tubing with the device elements fixed to it along the section of the perforated casing string, which serves as the device body.

The authors know the technical solution regarding the electric heating system for cleaning the well from paraffin deposits / Patent No. 33376, C10G 31/06, 10.20.2003 / with fixing the device elements on the outer surface of the tubing, which, however, does not provide mechanical dynamic effects on the well for the lack of pumping working agent. Accordingly, it is not suitable for cleaning perforation and PZP channels from drilling fluid, from scaling and mechanical impurities introduced into perforation and PZP channels during well killing and KRS / ORS (overhaul and underground well repairs).

The authors also know the possibility of mechanical cleaning of the well during tripping operations of the tubing string, on which scrapers are fixed on the outer surface in the form of wire brushes, etc. / Patent No. 2135758, ЕВВ 43/22, 08/27/1999 /; however, it is not possible to clean the perforation channels in this way.

The inventive device is illustrated by figures 1-3, where: 1 - device; 2 - plot perforated casing, performing the function of the housing of the device; 3 - tubing; 4 - stator; 5 - holes in the stator; 6 - rotor with an impeller; 7 - impeller channels; 8 - an element that seals the space between the stator and the housing; 9 - a fitting element, for example a metal washer.

The above-mentioned term “device elements to be moved onto the tubing” thus includes the following items in figures 2 and 3:

4 - a stator with holes 5 and a sealing element 8,

6 - rotor with an impeller and channels 7,

9 - fitting element.

Figure 1 presents a General diagram of a possible downhole layout of the inventive devices for implementing the method.

Figure 2 presents a schematic diagram of a device.

Figure 3 presents a top view of the rotor of the device.

The inventive method is implemented by the following sequence of operations carried out by the operation of the device.

1. The descent of the device elements that are transferred to the tubing, mounted on the outer surface of the tubing, using a hoist to the area of the perforated part of the formation to be processed.

2. Pumping the working agent under pressure through the device simultaneously with the operation of raising and lowering the elements of the device to be moved to the tubing by the elevator from the surface by means of the tubing within the device body.

3. Continuation of the operation according to claim 2 - until the termination of the removal of the squid from the PPP.

For the purpose of more efficient targeted use and economy of the working agent, or, for example, to alleviate the problems of the subsequent disposal of the working agent, they can be additionally - after the operations described above in items 1-2, the following are carried out.

2a. Pumping the working agent under pressure through the device simultaneously with the lifting-lowering operation of the device elements being moved to the tubing by the elevator from the surface by means of tubing inside the device until the body is filled with it, after which the pumping is stopped without stopping the lifting and lowering of the device elements being moved to the tubing with surface through tubing within the device enclosure.

2b. The lifting and lowering of the device element to be moved to the tubing by the lift continues until the decontamination or production of the volume of the working agent.

2c. After deactivation or development of the volume of the working agent, pumping of a new portion of the working agent is additionally resumed or another working agent is pumped.

Operations 2a-2b-2c continue until the termination of the removal of the squid from the PPP.

Due to the design features of the inventive device associated with the installation of elements moved to the tubing, on the outer surface of the tubing, it is possible to simultaneously install and, accordingly, the simultaneous use of several devices. This allows you to implement the inventive method for the SCR formation of conditionally infinite thickness.

Provides selective cleaning of the perforation channels by moving the device in the perforation interval.

A device for cleaning the channels of perforation and processing of the bottomhole zone works as follows.

The working agent is pumped from the surface into the tubing (figure 1); upon reaching the free end of the tubing string, the working agent enters the annulus, in which on the outer surface of the tubing the elements of the device that are moved to the tubing are fixed, including (FIGS. 2, 3):

4 - a stator with holes 5 and a sealing element 8,

6 - rotor with an impeller and channels 7,

9 - fitting element.

Since the sealing element 8 prevents the passage of the working agent directly along the housing 2 of the device, the flow is directed to the holes 5 of the stator 4. Since the holes 5 are made at an angle to the plane of the impeller of the rotor 6, the high-pressure head of the flow causes the rotation of the impeller of the rotor 6. The flow flowing from the channels 7 rotor 6, has a tangential and radial velocity components. The radial component during the passage of the flow past the perforation channel in the housing 2 of the device generates pressure fluctuations in it. The tangential component of the flow generates high-frequency oscillations in the perforation channel of the housing 2.

Pressure fluctuations in the perforation channel contribute to the effective destruction and erosion of the squid present in the channel. High-frequency vibrations effectively destroy deposits on the surface of the channel and PZP.

The presence of the fitting element 9 provides when moving up and down the device elements that are moved to the tubing, the excitation of low-frequency disturbances in the processed interval (plunger effect), which, in turn, provides an effect on the squid in more remote zones of the PPP.

The device can work both on pure liquid or GHS, and, in principle, on gas. As working agents can be used:

- acid solutions;

- alkali solutions;

- surfactant solutions;

- oil;

- solvents;

- water is salty and fresh;

- foam systems

and others approved for use.

Before launching the device, the well is prepared by flushing with a template with a diameter equal to the diameter of the device, until the bottom.

The size of the device corresponds to the size of the well casing.

The downhole layout is determined by:

- lift capabilities (mast height - pipe, “candle”);

- thickness of the perforated interval;

- the presence of several perforation intervals, their relative position;

- binding to the bottom of the well.

A device, one or more, is mounted above the beveled end of the tubing through a pipe or two pipes (“candle”).

The indicators of the event are as follows.

When pumping a working agent and simultaneously raising the tubing:

- tubing lift speed from 1 m / min to 2 m / min,

- the fluctuation frequency in the perforation channel from 40 Hz to 80 Hz,

- pressure drop (loss) in the device from 0.5 atm. up to 1.0 atm. (from 0.05 MPa to 0.1 MPa).

When lowering the tubing without pumping the working agent and when lowering the tubing with pumping the working agent:

- tubing descent speed from 0.5 m / s to 1 m / s,

- the fluctuation frequency in the perforation channel: from 80 Hz to 200 Hz,

- pressure drop (loss) in the device: from 1.0 atm. up to 2.0 atm. (from 0.1 MPa to 0.2 MPa).

If there is no pumping of the working agent when lifting the tubing, the overflow of the working agent from the “above” position to the “under” device is for reuse.

Example

Processing was carried out at the production well. The productive stratum is composed of terrigenous sediments having a porosity of 24% in the zone of the bottom-hole zone. The casing is perforated in the interval 1920 ... 1948 m, a total of 28 m

The casing of the well has a nominal diameter of 146 mm with a wall thickness of 8 mm.

Cumulative perforation density of 20 holes per 1 m, a total of 560 holes.

Reservoir pressure 15 MPa.

Artificial slaughter was repelled at a depth of 1968 m, i.e. sump is 20 m.

The processing used elements of devices moved to the tubing with an outer diameter of 124 mm.

When implementing the method, the A-50 hoist was used with a tubing with a diameter of 73 mm and an average length of 10 m.

Three elements of the device moved to the tubing were lowered to the tubing and installed at a distance of 10 m from each other; moreover, the lower device was lowered to the level of the lower holes of the perforation interval, and the bottom of the tubing was on the artificial bottom.

The process was carried out in three stages.

1) With an open annular valve - continuous pumping through three devices of a gas-liquid mixture with a density of 0.8 ... 0.2 g / cm ³ with continuous movement of the device elements moved to the tubing up and down.

The purpose of the stage: hydromechanical decalmatization of perforation channels and PZP.

Result: on the surface, an intensive outflow of ARPD and clay solution was observed, which confirms that the plodding nature of the device actually provides, when moving up and down, the excitation of low-frequency disturbances in the processed interval (plunger effect), i.e. impact on remote zones of the PPP.

2) Filling the device casings (annular volume at the level of the perforation interval) with a clay-acid composition (GCC) with an open annular valve followed by the displacement of the GCC in the PPP with constant movement of the device elements up and down with the closed annular valve (i.e., when pumping is stopped, but with overpressure in the well) - the development of the volume of the working agent.

The purpose of the stage: physico-chemical decalmatization of the porous medium of the bottom-hole zone.

Result: the overpressure in the well decreased to atmospheric, which indicates the development of the volume of the working agent in the devices.

3) Repeating the operations in step 1.

The purpose of the stage: the extraction of products of physico-chemical effects from the porous environment of the BCP.

Result: on the surface there was an intensive removal of the reaction products of the HCC with particles of the skeleton of the rock and the reaction products of the HCC with clay and other calcining materials; those. the geological and technical event of the proposed method is completed.

Well operation parameters.

Before treatment: oil flow rate - 16 t / day, fluid flow rate - 25 m ³ / day.

After processing: oil flow rate - 60 t / day, fluid flow rate - 72 m ³ / day.

Claims (6)

1. The method of cleaning the perforation channels and processing the bottom-hole zone, including the descent of the elements of the device moved to the tubing to clean the perforation channels and processing the bottom-hole zone, made in the form of a stator and rotor with channels, pumping the working agent under pressure through the device, characterized in that the device is provided with a housing in the form of a section of a perforated casing string, and the stator is made in the form of washers with holes located at an angle to the plane of the rotor impeller, equipped with the element sealing the space between the stator and the device body, the fitting element and the stator are rigidly fixed on the outer surface of the tubing, the rotor is placed between the stator and the connecting element and is integral with the impeller, the lifting and lowering of the device elements fixed on the outer surface of the tubing is carried out with surfaces within the device enclosure. 2. The method according to claim 1, characterized in that the pumping of the working agent under pressure through the device is carried out until the case is filled with it, after which the pumping is stopped without stopping the lifting and lowering of the device elements that are transported to the tubing by the elevator from the surface via the tubing within the device . 3. The method according to claim 2, characterized in that the ascent-descent of the device elements moved to the tubing by the elevator continues until the decontamination or production of the volume of the working agent. 4. The method according to claim 3, characterized in that after deactivation or development of the volume of the working agent, pumping of a new portion of the working agent is additionally resumed or another working agent is pumped. 5. The method according to any one of claims 1 to 4, characterized in that the outer surface of the tubing is provided with several elements of several devices that are lowered simultaneously. 6. A device for cleaning the perforation channels and processing the bottom-hole zone, including a stator with holes rigidly fixed to the tubing, a rotor with channels, characterized in that the stator holes are made at an angle to the plane of the rotor impeller, the stator is a washer mounted on the outer surface of the tubing, equipped with an element that seals the space between the stator and the housing, the device is additionally equipped with a fitting element, rigidly fixed to the outer surface of the tubing, the rotor is located between the stator and pc tsiruyuschim element and is integrally formed with the impeller, it being possible to move the tubing fixed thereto elements of the device along the perforated portion of the casing, performing the function of the device body.

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