SU933952A1 - Method of operating an oil well - Google Patents

Description

(B) METHOD OF OPERATION OF OIL WELL

The invention relates to the oil and gas mining industry and can be used to prevent the formation of gas cones during oil production from wells operating oil and gas horizons. A known method of forming an impermeable barrier in the zone of gas-oil contact of the reservoir, in which a reduction in the flow of gas into the oil well is achieved. Horizontal cracks are created around the well, in the walls of which pressure is insoluble in oil and gas material, which clogs the pores in adjacent rocks and makes them impermeable. The crack is filled with cement mortar, which, after hardening together with the treated rocks in the crack wall, forms a horizontal barrier with low permeability LIJ. However, the method does not have high reliability and e (M) efficiency, since the process of creating horizontal cracks is difficult to control and the cracks often do not overlap the required area of contact of oil with gas. The technical and technological difficulties of implementing the method make it practically unacceptable in fields with thin oil rims and a gas zone of small power. There is a method of operating an oil well, which involves extracting oil from a reservoir by creating a depression, blocking the gas-saturated part of the reservoir to prevent gas breakthrough into the well by perforating the casing in the gas-saturated part of the reservoir and pumping an aqueous solution of surfactant 2; ) effectiveven due to low gas permeability reduction.

The purpose of the invention is to increase the reliability of blocking the gas-saturated part of the formation.

This goal is achieved in that according to the method of operating an oil well, which consists in extracting oil from the reservoir by creating a depression, blocking the gas-saturated part of the reservoir to prevent gas from breaking into the well by perforating the casing in the gas-saturated part of the reservoir and pumping an aqueous solution of the surfactant substances, the placement of perforated holes in the casing string is produced according to a logarithmic law, and before injection; Hydrocarbon condensate is injected with an aqueous solution of surfactant.

Moreover, the placement of the perforations according to a logarithmic law is carried out with an increase in the perforation density to the gas-oil contact zone.

In addition, the injection of condensate and an aqueous solution of surfactant is produced t periodically.

The drawing shows a device for implementing the proposed method

Well 1 opens the gas 2 and oil 3 zones of the reservoir and is perforated at these intervals. At the same time, in the gas-saturated zone, perforation is carried out according to a logarithmic law with an increase in the perforation density to the gas-oil contact zone 5. Then, a string of lifting pipes 6 with a packer 7 installed at the gas-oil nbgo contact level are lowered into the well. After that, condensate 8 and an aqueous solution of surfactant 9 are pumped into the wells. Then the well for hours, depending on the anisotropy and the ratio of the saturation pressure to the reservoir pressure, is operated with a maximum allowable flow rate to form a gas-oil contact

10 foam formation.

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The volumes of the condensate and the aqueous surfactant solution required for injection are determined by calculation taking into account the flow rate of the well, the physicochemical properties of the reservoir and the fluids that saturate it, the reservoir geometry, based on the gasless operation of the well for a period . The average volume of condensate and aqueous solution of surface-active solution varies from 30 to 150 m, calculated on the gas-free operation mode of the well for 12-18 months, and the condensate is 25% by volume more than the aqueous solution of surface-active solution. The proposed method was tested on the stand.

The experiment was carried out on cylindrical core samples with a diameter of 30 mm and a sample length of 50 mm taken from one well. The air permeability of samples is 6% different.

The first sample is saturated with an aqueous solution of the Disolvan concentration surfactant solution Q, k% over the entire pore volume. ZM pore volume of the second sample is saturated with condensate, the rest of the aqueous solution of the surface-active solution of the same concentration. On the one hand, core samples are injected with natural gas at a pressure of k kgf / cm to break through on the other, and in the second sample gas is injected from the side saturated with condensate and the time of gas breakthrough is measured.

In a sample saturated with a surfactant, a gas breakthrough occurred after 30 minutes, and in a second sample — after 55 minutes.

The eccentric performed showed that a core sample saturated with condensate and an aqueous solution of a surfactant, a condensate surfactant with a saturation sequence, has a greater ability to block natural gas than a core sample saturated only with an aqueous solution of a surfactant.

The proposed method for preventing gas breakthrough into oil wells provides for ease of implementation, reliability and efficiency at the expense of longer gas-free operation of wells.

Claims (3)

1. A method of operating an oil well, consisting in extracting oil from a formation by creating a depression, blocking a gas-rich layer of formation to prevent gas breakthrough into the well by perforating a casing in a gas-saturated part of the formation and injecting an aqueous solution of a surfactant, characterized by in order to increase the reliability of blocking the gas-saturated part of the reservoir, the placement of perforated holes on the casing string is performed according to a logarithmic law, and before being pumped into -stand solution of surfactant is injected hydrocarbon condensate. 2. The method according to claim 1, characterized in that the placement The log holes are logarithmically performed with increasing perforation density to the gas-oil contact zone. 3. The method according to claim 1, characterized by the fact that condensate and an aqueous solution of surfactant are injected periodically. Sources of information taken into account in the examination 1. US Patent K 3237690, cl. 166-29, published. 1961. 2. US patent number 336862 Cl. 166-29, o.publik. 1968.