Super-hydrophobic downhole oil-water separator and its injection-production string in the same well

Abstract

The invention relates to a super-hydrophobic downhole oil-water separator and a same-well injection-production process pipe column thereof. The super-hydrophobic downhole oil-water separator comprises an outer cylinder. The outer side of the top of the outer cylinder is hermetically connected with an upper joint, the bottom of the outer cylinder is hermetically connected with a lower joint, and a pump cylinder is arranged hermetically and slidably on the inner side of the top of the outer cylinder in a penetrating mode. A first one-way valve is arrange on the inner upper portion of the pump cylinder, the bottom of the pump cylinder is fixedly connected with an annular piston in the circumferential direction, and a second one-way valve is arranged on the inner lower portion of the pump cylinder. A super-hydrophobic separation tower plate structure is arranged inside the outer cylinder, a third one-way valve is arranged on the middle portion of the side wall, a fourth one-way pressure-limiting valve is arranged at the bottom of the outer cylinder, and an outlet of the fourth one-way pressure-limiting valve is connected with an inner cavity of the lower joint. The super-hydrophobic downhole oil-water separator is simple in structure, adjustable in processing capacity, and high in separation efficiency.

Description

technical field [0001] The invention relates to the technical field of oilfield development, in particular to a super-drainable downhole oil-water separator and a same-well injection-production process string. Background technique [0002] In the middle and late stages of heterogeneous reservoir development, there are more and more wells with high water cut, and the water cut of many wells has reached 98%. The cost of surface produced fluid treatment has greatly increased, and it has reached or approached the economic and technical limit of production, making it impossible to continue production. In order to solve this problem, the same-well injection-production technology using downhole oil-water separator to separate water and inject it into the formation in situ was proposed. [0003] At present, the downhole oil-water separation devices that are widely used in mines mainly include gravity-type and cyclone-type oil-water separators. Because the gravity oil-water separato...

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Problems solved by technology

Because the gravity oil-water separator is affected by the settling time, the processing capacity is not large, the separator column is long and the settling components accumulate inside the separator, which seriously affects the service life, and the field application is gradually reduced; most of the wells currently use cyclone type oil-water separator, but the swirl-type oil-water separator needs to be used with an electric submersible pump, which cannot be applied to conventional rod pump oil production wells, and according to the statistical data of field tests, its success rate is only 50%, and it cannot be widely promoted use

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