RU2003779C1 - Method of construction of wells - Google Patents

Abstract

The invention relates to the cementing of casing strings in wells. Summary of the invention: before the production casing is run, the interval of occurrence of the productive formation is determined. The production casing is equipped with legal packers to be placed above and below the production formation. The production string is made with side openings. They are carried out on the lower funnel packer. The lateral openings are blocked by elements temporarily separating the internal cavity of the production string from the external space. Then the production string is lowered into the well. The descent is carried out with the closure of the productive formation by this column. Slurry mortar and squeezing liquid are pumped into the bacon space. After injection of the grouting mortar, the inner space of the production string is hydraulically communicated with the outer space. Then, the pumping fluid is injected until the cement slurry and the interval of the reservoir are displaced. The latter is isolated with the help of punctured packers. After this, fracturing of the reservoir is carried out

Description

FIELD OF THE INVENTION This invention relates to the oil industry, in particular to cementing casing strings in wells.

A well-known method of well construction is used, in which the injection of cement slurry is alternated with pumping of the drilling fluid and in the viscoelastic separator, which reduces shrinkage and crack formation in the cement stone,

A disadvantage of the known method is its low manufacturability due to the need to switch cementing equipment to alternate pumping of the grout, slurry fluid and viscoelastic separator.

The closest technical solution, taken as a prototype, is a method of constructing wells, including lowering a production string that overlaps the reservoir, pumping continuously one after another into the annulus of the insulating cement slurry and permeable cement slurry located opposite the reservoir, and the implementation of the hydraulic fracturing after setting the insulating cement slurry,

The known method is not technologically advanced, so kik is required to interrupt cementing while waiting for the insulating cement slurry to set, and hydraulic fracturing after it sets can lead to deformation of the cement stone obtained from the insulating cement slurry.

The essence of the invention consists in increasing the efficiency of well construction and tightness of the annulus while ensuring manufacturability, which is achieved by determining the interval of occurrence of the reservoir before the production string is run, equipment of the production string before it is run by the packers with the condition of their placement above and below the production formation, implementation of the production string above the bottom annular packer with side holes overlapped elements temporarily separating the internal cavity of the production casing from the external space, and after the cement slurry is injected into the annular space, the internal space of the production casing is hydraulically communicated with the external space, after which the squeezing fluid is pumped up to. grouting displacement

from the interval of the reservoir, and before hydraulic fracturing of the reservoir, the latter is isolated with column packers.

The method is implemented as follows.

After completion of well drilling, geophysical surveys determine the interval of occurrence of a productive formation, for example, a roof at a depth of 2560 m, and the sole of the formation at a depth of 2570 m. The production casing is equipped with two casing packers installed in the intervals of 2556-2560 m and 2570-2574 m. Above the lower packer, place a device with side openings overlapped

elements temporarily separating the internal cavity of the production casing from the external space.

The production casing with a diameter of 0.146 m is lowered to a depth of 2620 m, at

this annular packers are located above and below the reservoir. 30 m3 of cement slurry are prepared and pumped into the column. After grouting grouting into the annulus

the space through the shoe of the production casing receives a moment - stop at a pressure on the cementing head of 15 MPa. The pressure on the cementing head is increased to 16.0-16.2 MPa, while

elements temporarily blocking the side openings in the device mounted above the lower packer break and open the openings. Pumped through side holes in the production casing

0.2 m of sales fluid and displace the grout from the interval of the reservoir.

After that, the reservoir is isolated from above and below by casing packers

and raising the pressure in the column to fracture the formation. Special fluids are used to prevent contamination of the reservoir. Lowered into operational

column lift pipes and receive inflow from the reservoir.

(56) Copyright certificate of the USSR No. 1454952, cl. E 21 B 33 / 13.1989. USSR copyright certificate No. 1164397, cl. E 21 B 33/13, 1985.

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Claims (1)

The claims METHOD FOR CONSTRUCTION OF WELLS, which includes lowering the production casing with shutting off the reservoir, pumping grouting mortar, squeezing fluid into the ecolon space, and characterized in that before the production casing is determined, the bedding interval is determined, and the production casing is equipped with casing packers with the condition of their placement above and below the reservoir and are performed with side holes above the lower ecolon packer, shutoff elements temporarily separating the inner cavity of the production string from the outer space, and after the grouting mortar is injected into the annular space, the inner space of the production string is hydraulically communicated with the external space, and then the squeezing fluid is pumped until it is displaced cement slurry from the reservoir of the reservoir, and before hydraulic fracturing of the reservoir I isolate the latter using -zakolonnyh packers. 0