A well completion method

Abstract

The method pertains to the oil and gas industry and can be used in the development of producing formations. A producing string (6) together with a sealing device (7) are lowered into a well (1) and the well (1) is divided into an upper cavity (8) and a lower cavity (9) with the aid of said sealing device (7) to establish a hydraulic connection between the well opening and the upper cavity and between the lower cavity and the producing formation, respectively. The installation of equipment (10) and a check valve is carried out stepwise. A washer fluid (4) is replaced by a washer fluid (15). The equipment (10) is passed through the sealing device (7) and the hydraulic connection between the well opening, the lower cavity and the producing formation is re-established along the annular channel. The well (1) is deepened using the equipment (10) until an inflow of formation fluids occurs, the differential pressure in the hydraulic system “well opening—producing formation” being adjusted using the check valve and a blowout preventer (3). The equipment (10) is withdrawn from the lower cavity (9) upon completion of deepening, the device (7) is closed during separation of the cavity (9) from the cavity (8) and cutting-off the hydraulic connection between the producing formation and the upper cavity. The technical solution increases the efficiency and quality of technical operations and prevents the undesired inflow of formation fluids.

Description

TECHNICAL FIELD[0001]The invention pertains to the oil and gas industry, namely to drilling and operation of oil and gas wells, and can be used in the development of producing formations and well completion.PRIOR ART[0002]According to a known method of primary development of producing formations in the course of drilling for oil and gas, optimum conditions for primary development are produced with the use of different compositions of drill fluid, RU No. 2283418 C2, E21B21 / 00, 10 Sep. 2006.[0003]The known method relates to selection of reagents added to the drill fluid depending on the stage of operations performed on development of producing formations.Another known method of well completion consists of primary development of the producing formation, fastening of producing strings and secondary development of the producing formation, RU No. 2140521 C1, E21B33 / 13, 27 Oct. 1999.[0004]The known method provides decrease in the overbalance on account of overlapping of high-pressure forma...

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Benefits of technology

[0016]The invention solves the problem of increasing the efficiency and quality with which t

Problems solved by technology

When washer fluid is pumped, the overbalance on the bottomhole (accounting for the pressure loss in annulus and pressure of immersed jet coming from the bit nozzles) increases.

In the “closest analog”, during the development of producing formation the formation fluid inflows are prevented by creation of overbalance by the washer fluid column, which leads to absorption, increase in washer fluid flow rate, reduction of effective permeability of the producing formation and decrease in oil production.

Excess of washer fluid pressure over the formation pressure leads to i

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