RU2474674C1 - Well cleaning method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: when the well is being cleaned, a layout consisting of a pipe string and a hydraulic sludger is lowered to the well. Hydraulic sludger is opened and filled with borehole fluid and swab is lowered to the pipe string. The fluid is extracted via the pipe string with the swab and the layout is removed from the well. Layout bottom is interconnected with the well head via an individual pipeline with possibility of the pipeline shut-off or connection to the atmosphere. After the hydraulic sludger is filled with the borehole fluid and the swab is arranged in the pipe string, the hydraulic sludger is closed. After that, individual pipeline is connected to atmosphere. Then, fluid is taken from the pipe string and the sludger with the swab at the closed hydraulic sludger. Volume of the removed fluid is filled with air via the individual pipeline. Then, the swab is removed from the pipe string and hydraulic sludger is opened. Hydraulic sludger and pipe string is filled with borehole fluid. If necessary, the operations are repeated.

EFFECT: improvement of the cleaning process.

1 cl, 1 dwg

Description

The invention relates to techniques and technologies for the production of hydrocarbons and can find application in cleaning a wellbore or formation of an producing, injection or artesian well from deposits on the bottom of the well and floating debris in the well fluid,

A well-known well complex for conducting flushing technology, consisting of technological equipment for conducting underground and major repairs of wells, production casing, tubing, base part, modular part for cleaning the bottom hole and the modular part for cleaning the bottom-hole formation zone. The basic part includes the technological layout of the hydraulic valve with a bypass valve with an adjustable throttle clutch and pipes with the ability to adjust the fluid flow rate to create depression and use the hydrostatic pressure drop, which provides a complete cleaning cycle. The modular part for cleaning the bottom hole contains a drill bit with the possibility of milling and loosening sand plugs, and the modular part for cleaning the bottom-hole zone of the formation includes a slit pipe filter, a screening centralizer and equipment in the form of tubing, which are both a container for collecting dirty liquid and sludge ( RF patent No. 84048, IPC Е21В 27/00, published on June 27, 2009).

Closest to the proposed invention by technical essence is a method of cleaning a well, described during the operation of the technological layout for well development (RF Patent for utility model No. 106649, publ. July 20, 2011 - prototype). The technological layout for well development includes a production casing of a well with killing fluid and a bottomhole formation zone with perforations and consists of equipment for swabbing a well, production pipes with bottomhole fluid, a slit pipe filter installed opposite the perforation holes of the formation and a liner resting on a previously cleaned bottom wells, and to ensure the possibility of effective cleaning and development of the zone of the reservoir, the regulation a removable hydroprotector with containers to create a single channel from the bottom to the wellhead for fluid movement and collection of sludge and other clogging deposits in containers.

In the known method, after installing an adjustable hydraulic valve with process pipes and lowering the technological layout for developing wells at the drainage site, the technological layout is unloaded. The pipe slit filter is positioned so that the slot slots are located opposite the perforation holes of the production casing of the well. After triggering an adjustable hydraulic valve with containers due to the difference in hydrostatic pressure, mud from the bottomhole formation zone is sucked into the containers of an adjustable hydraulic valve. When stabilizing the liquid level and pressure in the containers of the adjustable hydraulic valve, equipment for swabbing wells is mounted. Swabbing technology is performed according to the standard scheme with an open choke before calling and stabilizing the flow of fluid from the reservoir. The layout is lifted up to release the adjustable hydrotank containers from sludge. The proposed technological layout for well development allows you to use the positive qualities of the swab technology and the use of adjustable hydraulic wells with containers for well development.

The disadvantage of this technical solution is that the sequential effect of the hydraulic valve and the swab is not able to completely clear the strongly clogged near-wellbore zone. The impact of the swab is much weaker than the hydroprotection, and if further cleaning is necessary, then it is necessary to carry out a second round-trip operation of the hydroprotection and its operation.

The proposed invention solves the problem of increasing the efficiency of cleaning the near-wellbore zone and the well from contamination due to repeated exposure to a hydro-gel without carrying out hoisting operations.

The problem is solved in that in a method of cleaning a well, which includes lowering into the well an arrangement consisting of a pipe string and a hydraulic valve, opening and filling the hydraulic valve with well fluid, lowering the swab into the pipe string, taking fluid from the pipe string with the swab, and lifting the layout from the well, according to the invention is informed of the bottom of the layout with the wellhead by a separate pipeline with the possibility of blocking the pipeline or communication with the atmosphere, after filling the hydroprotection with the borehole fluid and placing the swab in the column t rub close the hydrogel, report a separate pipeline with the atmosphere, take the fluid from the pipe string and choke with a swab when the hydroscope is closed, fill the volume of the sampled fluid with air through a separate pipe, lift the swab from the pipe string, open the water tank, fill the water tank and pipe string with borehole fluid, if necessary operations are repeated.

SUMMARY OF THE INVENTION

The pressure on the bottom of the well, created by the hydro-gel, very effectively cleans the well and the near-wellbore area from contamination. However, for severely contaminated conditions, a single exposure is not sufficient for final cleaning. The vacuum created by the hydrogel is disposable, and for its repetition, it is necessary to lift the hydrogel from the well, clean it and then lower it back into the well. Hoisting operations are very long, expensive, and repeated exposure to a hydrotank can again not lead to final cleaning of the well and the near-wellbore zone from contamination. The proposed invention solves the problem of increasing the efficiency of cleaning the near-wellbore zone and the well from contamination due to repeated exposure to a hydro-gel without carrying out hoisting operations. The problem is solved as follows.

An assembly for cleaning is lowered into the well, which consists of a pipe string, a hydroprotector, a slit tube filter installed opposite the perforation holes of the formation, a liner resting on the bottom of the well and a separate pipeline. Figure 1 shows the layout for implementing the inventive method, where 1 is the equipment for swabbing, 2 is a separate pipeline, 3 is a pipe string, 4 is a hydroprotector, 5 is a slotted filter, 6 is a shank.

Inside the hydraulic valve there is a valve that opens when the layout is on the bottom and closes when the layout is raised. A hydraulic pump with a pipe string creates a single channel from the bottom to the wellhead for fluid movement with contamination. When emphasis is placed on the bottom, the flap is activated, i.e. opens, and its internal volume, filled with air, communicates with the borehole fluid. When rising from the bottom, the choke closes. After actuation of the hydroprotection due to the difference in hydrostatic pressure, pollution from the near-wellbore zone and from the well is sucked into the hydroprotector and pipe string. The filling of the hydraulic valve and the pipe string ends when the liquid level and pressure in the pipe string are stabilized. Report the bottom of the layout, for example, the internal volume of the hydraulic valve or the bottom of the pipe string with the wellhead, a separate pipeline with the possibility of blocking the pipeline at the wellhead or communication with the atmosphere. During the actuation of the hydraulic valve, it is desirable that a separate pipeline be closed at the wellhead. This will reduce the likelihood of contamination when the well fluid enters the hydroprotection and pipe string.

The layout is supported on the bottom of the well and trigger the hydraulic valve. The hydraulic valve and pipe string are filled with well fluid with contamination. From the wellhead, a swab with a pulling body is placed in the pipe string. Raise the layout and close the hydroprotection. A separate pipeline with the atmosphere is reported and liquid is taken from the pipe string and the choke with a swab when the hydroprotector is closed, filling the volume of the selected liquid with air through a separate pipe. Fill the layout with air. Raise swab from the well. In this case, it is desirable to block a separate pipeline at the wellhead. The layout is supported by the bottom hole, which causes the hydraulic valve to operate and the hydraulic valve and pipe string to be filled with borehole fluid. If necessary, the operations are repeated until “clean” water appears during swabbing. The layout is lifted from the well.

Concrete example

They clean the oil producing well with a depth of 1750 m. Previously, it was not possible to clean the well and the near-borehole zone and cause the influx of formation products by known methods. An assembly is lowered into the well, including a tubing string with a diameter of 73 mm, a hydroprotector, a slit tube filter and a liner. The internal volume of the hydraulic valve is connected to the wellhead by a separate pipeline from an armored capillary tube with a diameter of 13 mm. A valve is provided at the mouth to shut off a separate pipeline. Close the valve. The layout is supported on the bottom of the well and trigger the hydraulic valve. The hydraulic valve and pipe string are filled with well fluid with contamination. From the wellhead, a swab with a pulling body is placed in the pipe string. Raise the layout and close the hydroprotection. A separate pipeline with the atmosphere is reported and liquid is taken from the pipe string and the choke with a swab when the hydroprotector is closed, filling the volume of the selected liquid with air through a separate pipe. The swab fluid is withdrawn with a gradual immersion of the swab under a decreasing fluid level in the pipe string. Fill the layout with air. Raise swab from the well. The layout is supported by the bottom hole, which causes the hydraulic valve to operate and the hydraulic valve and pipe string to be filled with borehole fluid. They again raise the layout until the hydroprotection is closed. The operations are repeated 3 times. As a result, when swabbing, “pure” water appears, and then the oil emulsion — formation products. The well is cleaned of impurities, caused by the influx of reservoir products. The layout is lifted from the well.

The application of the proposed method will improve the cleaning efficiency of the near-wellbore zone and the well from pollution.

Claims (1)

A method of cleaning a well, including a descent into the well of an assembly consisting of a pipe string and a hydraulic valve, opening and filling the hydraulic pump with a borehole fluid, descent into the pipe string of the swab, withdrawing fluid from the pipe string with the swab, and raising the layout from the well, characterized in that the bottom of the assembly is informed with the wellhead with a separate pipeline with the possibility of blocking the pipeline or communicating with the atmosphere, after filling the hydroprotector with the borehole fluid and placing the swab in the pipe string, close the hydroprotector, inform an atmospheric pipeline, liquid is taken from the pipe string and the choke with a swab when the hydrogel is closed, filling the volume of the sampled fluid with air through a separate pipeline, the swab is lifted from the pipe string, the hydrogel is opened, the hydraulic pump and pipe string are filled with borehole fluid, and if necessary, the operations are repeated.