RU2296215C1 - Method for well bottom zone treatment - Google Patents

Abstract

FIELD: oil production industry, particularly to develop and operate wells, to perform well stimulation for well reworking and highly contaminated well injectivity recovery.

SUBSTANCE: method involves lowering assembly connected to flow string within well perforation interval, wherein the assembly comprises packer and paired rod pump including upper and lower bodies connected with each other by means or perforated pipe, rod stem with piston and ultrasound generator; separating tube space over perforation interval by means of packer; applying action of elastic ultrasonic vibrations in active technological liquid and acid solution on well bottom zone; removing reaction products along with washing-out treatment products; applying ultrasound action on formation; providing alternating liquid flow within perforation interval and light depression pulses. The ultrasound generator is mechanical generator, which is actuated by liquid flow passing through it in one direction. Ultrasound is applied along with liquid pumping into flow string at the forth pump operation stage.

EFFECT: increased efficiency of well and well bottom zone cleaning, improved output, simplified technology and decreased costs for well bottom treatment.

1 ex, 2 dwg

Description

The invention relates to the oil industry and may find application in the operation of the well, during the intensification work associated with cleaning the reservoir of the reservoir from contaminants, and restoring flow rate in the wells, to restore the injectivity of carbonate reservoirs of injection wells.

A known method of cleaning oil and water wells. Cleaning the bottom-hole zone of the well in the known method is based on the removal of colmatants by periodic exposure of the borehole space to elastic vibrations. Pre-process geological, geophysical, hydrodynamic information and the dynamics of the main parameters in the process of operating wells in the field. Based on the results of information processing, wells with high reservoir pressure, but cogged, are selected. Set the necessary parameters of elastic vibrations and determine the mode of exposure. Then they act on the selected productive intervals of the bottom-hole zone by a field of elastic vibrations with established parameters. Correct modes and nature of the impact according to the results of controlling the rate of removal of colmatants from the bottomhole zone. Evaluate the effectiveness of the impact and the data correct the operating mode of the wells (RF Patent No. 2151273, CL E 21 B 37/00, publ. 2000.06.20).

The known method is not effective enough due to the fact that it uses only one type of exposure - the field of elastic vibrations without combining with other types of exposure, for example chemical.

Closest to the proposed invention in technical essence is a method of complex processing of the bottom-hole zone of the well. The method includes descent into the well on the tubing string of the arrangement with an ultrasonic generator, impacting the bottom-hole zone of the well with elastic vibrations of ultrasonic frequency in the medium of an active process fluid and an acid solution. The composition of the arrangement lowered into the well on a tubing string includes a packer, a twin rod pump with a housing consisting of an upper and lower housing connected to each other by a perforated nozzle, and a rod string with a plunger. The annulus is separated by the packer above the perforation interval. Ultrasonic exposure is carried out in the perforation interval. As an active process fluid, a solvent of asphaltene-tar-paraffin deposits is used. After pushing the acid solution into the formation, technological shutter speed is performed to react the acid. Then produce drainage of the formation with the creation of alternating fluid movement in the interval of perforation and weak depressive impulses with constant exposure to the formation by ultrasound with pumping of reaction products and simultaneous washing out of treatment products (RF Patent No. 2261986, class E 21 B 43/18, publ. 2005.10. 10 is a prototype).

The disadvantage of this method is the need to power the ultrasonic generator through an electric cable, fixed with clamps on the tubing string, which creates certain difficulties during tripping operations, the need to be equipped with expensive equipment, and additional energy consumption during well treatment. In addition, continuous exposure to ultrasonic vibrations leads to an unjustified waste of energy, because only the effect that is performed in part of the pump cycle when the fluid moves from the formation to the well is useful.

The invention solves the problem of increasing the efficiency of cleaning the well and its bottom-hole zone, increasing the flow rate, simplifying the technology and reducing the cost of the process.

The problem is solved in that in a method for processing a bottom-hole zone of a well, including a descent into the interval of perforation of a well on a tubing string of an arrangement comprising a packer, a paired sucker rod pump with a housing consisting of an upper and lower housing interconnected by a perforated nozzle, a rod string with a plunger and an ultrasonic generator, isolation of the annulus by the packer above the perforation interval, impact on the bottom-hole zone of the well by elastic vibrations of ultrasonic frequency in the medium a active technological fluid and acid solution, pumping out reaction products while washing away the processed products, creating alternating fluid motion in the interval of perforation and weak depressive pulses, according to the invention, a mechanical sound generator is used as an ultrasonic generator, triggering when a fluid stream passes in it in one direction, and the ultrasonic effect is performed when the fluid is pumped into the tubing string on the fourth part of the qi Cla pump operation.

The features of the invention are:

1. descent into the interval of perforation of the well on the tubing string of the assembly comprising a packer, a paired sucker rod pump with a housing consisting of an upper and lower housing interconnected by a perforated nozzle, a rod string with a plunger and an ultrasonic generator;

2. uncoupling by the packer of the annulus above the perforation interval;

3. the impact of elastic vibrations of ultrasonic frequency in the environment of the active process fluid and acid solution;

4. evacuation of reaction products with simultaneous leaching of treatment products;

5. exposure to ultrasound;

6. creation of alternating fluid motion in the interval of perforation and weak depressive impulses;

7. the use as a ultrasonic generator of a mechanical sound generator that is triggered when a fluid stream passes in it in one direction;

8. ultrasonic action when pumping liquid into the tubing string in the fourth part of the pump cycle.

Signs 1-6 are common with the prototype, signs 7, 8 are the essential distinguishing features of the invention.

SUMMARY OF THE INVENTION

Known methods for processing the bottom-hole zone using ultrasonic treatment use electric ultrasonic generators. Their disadvantage is the need to power the ultrasonic generator through an electric cable, which leads to a significant consumption of electricity. There are certain difficulties during tripping operations, the need to be equipped with expensive equipment during well treatment. Continuous exposure to ultrasonic vibrations leads to an unjustified waste of energy, because only the effect that is performed in part of the pump cycle when the fluid moves from the formation to the well is useful. The invention solves the problem of increasing the efficiency of cleaning the well and its bottom-hole zone, increasing the flow rate, simplifying the technology and reducing the cost of the process. The problem is solved by the following set of operations.

When processing the bottom-hole zone, in the interval of perforation of the well on the tubing string, an assembly is lowered containing a packer, a paired sucker rod pump with a housing consisting of an upper and lower housing interconnected by a perforated pipe, a rod string with a plunger and a mechanical ultrasonic valve-type generator, triggered when a fluid stream passes in it in one direction. In the tubing string, when the packer is not installed, the bottom of the well and part of the bottomhole zone are filled with an active process fluid, for example, a solvent of asphalt-resin-paraffin deposits. A technological exposure is carried out for at least 16 hours and a solution of hydrochloric acid of 10-20% concentration is pumped into the bottomhole zone. The annulus is separated by the packer above the perforation interval. At the wellhead, a rocking machine is put into operation, under the influence of which the column of rods and the plunger of the pump make a reciprocating movement. At the same time, the arrangement performs an impact on the bottom and bottom-hole zones of the well with elastic vibrations of ultrasonic frequency in the medium of an active process fluid and acid solution, pumping out reaction products while washing out the treatment products, exposing the formation to ultrasound, creating alternating fluid movement in the interval of perforation and weak depressive impulses. Ultrasonic exposure is performed when the pump supplies liquid to the tubing string on one quarter of the pump cycle.

The work of the layout allows for highly effective cleaning of the bottom-hole zone of the formation and the involvement of low-permeability layers in the operation. As a result, the flow rate of the well increases and can even exceed the original due to the involvement of low-permeability layers in operation, the level of water cut in the formation fluid decreases.

The layout of the underground equipment used is shown in FIG. 1. The layout includes a drainage and depression twin rod pump, the housing of which consists of two bodies: the upper body 1 and the lower body 2, interconnected by a perforated pipe 3. A wide-cone valve is located in the lower part of the lower body 2 type 4, an ultrasonic valve generator type 5 and a filter are installed below 6. A drainage and depression pump is suspended on a tubing string 7. A plunger is installed inside the pump, with toyaschy of two standard plungers 8 interconnected. The plunger 8 is equipped with a suction valve 9 and is suspended on a string of rods 10. The arrangement is placed in a well equipped with a casing 11 in the perforation interval 12. A generator of elastic vibrations of the valve type 5 is located opposite the productive formation 13. 200-300 m above the pump between the pump compressor pipes 7 and casing 11 (in the annulus) placed the packer 14.

An ultrasonic valve type 5 generator is shown in FIG. 2. The generator consists of a valve 15 and a valve 16 located therein in contact with the partitions 17. The valve 15 is fixed in the hole 18 of the faceplate 19, which is mounted in the coupling 20. The coupling 20 is connected to the lower end of the lower housing 2 of the drainage-depression pump. The filter 6 is attached to the bottom of the coupling 20. The valve 16 is located in the valve 15 with play.

Elastic vibrations are generated by the fluid flow passing through the partitions of the valve 17 and valve 16 of the valve 15 with a specially selected backlash. Valve 16 vibrates at a frequency of 50-100 Hz. The cause of the vibration is a flutter phenomenon arising from the flow of fluid between the valve 16 and the valve baffle 17. The frequency of elastic vibrations depends on the diameter of the valve 15, the backlash amplitude of the valve 16, the speed and viscosity of the fluid passing through the valve 15.

The processing of the bottom-hole zone of the well is as follows.

Place the arrangement in the well so that the elastic oscillation generator 5 is in the center of the perforation interval 12. On the rod string 10, the plunger 8 is lowered and installed 5 meters above the pump to allow fluid to pass through the tubing string 7, the upper pump housing 1 and perforated pipe 3 in the perforation interval 12. Through the tubing string 7, the solvent is injected with asphalt-resin-paraffin deposits and acid is injected into the perforation interval 12. The plunger is planted 8 into the pump 1 and 2. Install the packer 14. Carry out technological exposure to dissolve the asphalt-resin-paraffin deposits and the reaction of the acid. For example, an A-50 type hoist lifts and lowers a rod string 10 with a plunger 8 with a plunger amplitude of 3 to 6 m. The pump can be composed of two pumps 1 and 2 with the same or different diameters: 32 mm per 43 mm, 43 mm by 56 mm, 56 mm by 68 mm, 68 mm by 98 mm. A pump with a smaller diameter is located below. For pumps 1 and 2 with diameters of the plungers 8 32 - 43 mm in the generator 5 (figure 1) it is recommended to use valve 1 (figure 2) with a diameter ^of _1/2 ", for pumps 1 and 2 with diameters of the plungers 8 of 56 mm and above (figure 1) - valve 5 (figure 2) with a diameter of 3/4 ".

During operation of the drainage-depression pump (Fig. 1), when the plunger 8 moves from the lower position upward, the formation fluid passes through a filter 6, an ultrasonic generator 5, a wide-passage valve of the cone type 4, and enters the pump housing 2. Under the plunger 8 creates a vacuum (pressure reduction). Ultrasonic generator 5 emits ultrasonic vibrations with a frequency in the range of 50-100 Hz. The fluid above the plunger 8 enters the string of tubing 7 and then to the wellhead. When the plunger 8 exits the lower housing 2 above the perforated nozzle 3, the uncompensated vacuum in the lower housing 2 is instantly filled with liquid, which enters the lower housing 2 through the perforated nozzle 3. In this case, a single depressive impulse is generated. At the same time, the movement of fluid through the ultrasonic generator 5 stops, and ultrasonic radiation stops. When passing the plunger 8 further up in the upper housing 1, the fluid under the plunger 8 enters through the perforated pipe 3.

When the plunger 8 moves downward, the wide-flow valve of the cone type 4 is closed, the liquid from under the plunger 8 is squeezed out through the perforated pipe 3 into the perforation interval 12. After the plunger 8 passes through the perforated pipe 3, the suction valve 9 of the plunger 8 opens, the fluid enters the plunger 8. Plunger 8 goes down. Ultrasound is not generated. Thus, a full cycle of movement of the plunger up and down the generation of the ultrasound field with a frequency of 50-100 Hz is made within _^1/4 cycle.

Due to the packing of the casing 11 above the perforation interval 12, the influence of an upstream liquid column is eliminated, which in turn allows more dynamic extraction of formation fluid. The whole process of processing the formation takes place in the space of the casing 11 limited by the packer 14.

If necessary, the process of changing the pressure in the sub-packer zone and the drainage process can be recorded by a pressure gauge, which is additionally placed under the filter 6. Data from the pressure gauge after completion of the formation treatment and extraction of the entire layout from the well is transferred to a computer and analyzed.

Concrete example

An operational well No. 1519 of the Kulushevsky oil field is processed with the following characteristics: the depth of the reservoir in the Tula horizon is 1377 m, the perforation interval is 1375-1378 m, the reservoir is terrigenous, the reservoir temperature is 27 ° C, the reservoir pressure is 12.6 MPa, the thickness of the reservoir 1 m, porosity 16.3%, oil saturation 65%, oil viscosity 100 mPa · s, oil density 0.863 t / m ³ , theoretical fluid rate - 3 m ³ / day, actual fluid rate - 1 m ³ / day, water cut - 5 %

The arrangement is placed in the well so that the elastic oscillation generator 5 is in the center of the perforation interval 12, i.e. 1375-1378 m at a depth of 1376 m. On the rod string 10, the plunger 8 is lowered and installed 5 meters above the pump. The column of tubing 7 injects a solvent of asphalt-tar-paraffin deposits - distillate and injects a 12% solution of hydrochloric acid into the perforation interval 12. Plunger 8 is planted in pump 1 and 2. Install packer 14. Carry out a technological shutter to dissolve asphalt tar and paraffin wax acid reaction within 24 hours. An A-50 type hoist raises and lowers the rod string 10 with plunger 8 with a plunger amplitude of 5 m. The pump is composed of two pumps 1 and 2 with the same diameters of 43 mm. In the generator 5 (Fig. 1), a valve 15 of the type 15h74p2M liquid valve (Fig. 2) with a diameter of 1/2 "is used. They work 36 hours, and 18 m ³ / day of fluid is taken. The packer is torn off. The layout is lifted. The RNAM pump is lowered. -20-125 and put into operation. The fluid flow rate amounted to 5.0 m ³ / day water cut - 5.0%. The result of the treatment of the bottom-hole zone is an increase in fluid flow rate from 1.0 m ³ / day to 5.0 m ³ / day - by 500%. Water cut remained unchanged.

The application of the proposed method will improve the cleaning efficiency of the well and its bottom-hole zone, increase oil production. The use of a mechanical ultrasonic generator instead of an electric one will reduce energy costs for the process, simplify the technology, and reduce the working time of the underground well repair team.

Claims (1)

A method for treating a bottomhole zone of a well, including a descent into the interval of perforation of a well on a tubing string of an assembly comprising a packer, a twin rod pump with a housing consisting of upper and lower bodies interconnected by a perforated pipe, a rod string with a plunger and an ultrasonic generator, uncoupling by the packer of the annulus above the perforation interval, the impact on the bottom-hole zone of the well by elastic vibrations of ultrasonic frequency in the medium of an active technological well fluids and acid solution, pumping out reaction products while washing treatment products, exposure to the formation by ultrasound, the creation of alternating fluid movement in the interval of perforation and weak depressive pulses, characterized in that a mechanical ultrasonic generator is used as an ultrasonic generator, which is triggered when a jet passes through it fluid in one direction, and ultrasonic action is performed when the pump supplies the fluid to the tubing string on Werth portion of the pump cycle.

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