Pre-set downhole filter and water filtering method

Abstract

The invention relates to a preset downhole filter and a water filtering method. The filter includes a work cylinder, a slotted screen part is arranged at the lower part of the work cylinder, and the bottom of the slotted screen part is sealed; the inner chamber of the work cylinder The lower part is provided with the first filter element assembly, and the inner cavity of the first filter element assembly can communicate with the slotted screen part; the upper part of the inner cavity of the working cylinder is equipped with the second filter element assembly, and the lower part of the second filter element assembly is provided with a flow joint; The inner cavity of the second filter element assembly is provided with a core tube, and the inner cavity of the core tube forms a fluid passage for the injected water to flow into the first filter element assembly, and the outer diameter of the core tube is smaller than the inner diameter of the first filter element assembly; preset type The downhole filter also includes a ball that seals off the top of the core. The preset downhole filter and water filtration method can solve the problem of deterioration of water quality in injection wells caused by the inside of the water injection string, realize the filtration of injected water downhole, prevent the pollution of the injected water along the way, and reduce the injection rate before injection into the formation. The concentration of suspended solids in water improves the quality of injected water.

Description

technical field [0001] The invention relates to the technical field of petroleum exploitation, and relates to a preset downhole filter capable of filtering injected water downhole and a water filtering method, and is especially suitable for use in water injection wells with poor water quality in low-permeability water drive development reservoirs. Background technique [0002] At present, water injection is widely used in oilfield development. The quality of injected water directly affects the development effect of oil wells. However, the injected water of water injection wells is only equipped with filtering devices at the ground joint station, water injection station, and water injection wellhead. It is not deployed in the downhole, and the water injection string cannot be solved. Internal problems of water quality deterioration in injection wells, such problems mainly include "the treatment capacity at the source does not meet the development needs", "the bacteria in the w...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a preset downhole filter and water filtration method, which can solve the problem of water quality deterioration in injection wells caused by the interior of the water injection pipe string, realize the filtration of injected water in the well, and prevent the injection water from leaking in the water injection pipe string. Pollution along the way is generated in the interior, the concentration of suspended solids in the injected water before being injected into the formation is reduced, and the quality of the injected water is improved.

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