Underground filter device for well logging during drilling

Abstract

The invention discloses an underground filter device for well logging during drilling. The filter device is provided with a screw shaft, a filter net, a sleeve, an upper connector and a lower connector, wherein an annular drilling fluid inlet is formed in the lower connector, and a post-filter annular drilling fluid outlet is formed in the upper connector. According to the technical scheme, a low pressure area is formed at the inlet by virtue of the rotation of the screw shaft, the annular drilling fluid is sucked into a test device, the filter fluid passes through the filter net to enter a filter fluid cavity under the extrusion effect of the screw shaft, and solid-phase particles are discharged to the outlet. The filter device can work continuously in an underground severe environment such as high temperature, high pressure and high corrosion and has a function of initiatively scraping a filter cake and backwashing the filter net, and the problem of filtering the underground solid phase can be solved; meanwhile, the underground filter device has characteristics of small size, simple structure, convenience in installation, reliability in work and the like.

Description

technical field [0001] The invention belongs to the field of oil and gas exploration and development, and in particular relates to a downhole filtering device applied to logging while drilling. Background technique [0002] At present, logging-while-drilling technology and related technologies of gas separation and detection are developing rapidly, and downhole gas detection while drilling has become a major research direction in the mud logging industry. Compared with the traditional surface gas logging, the downhole gas detection while drilling is to measure the dissolved gas (such as methane, carbon dioxide, sulfur Hydrogen, etc.) for real-time detection and analysis to determine whether the gas exists. [0003] Downhole gas detection while drilling technology takes gas as the research object. Firstly, it is necessary to collect annular drilling fluid into the downhole testing device, and then complete the separation of gas from the collected dr...

AI Technical Summary

Problems solved by technology

However, during the long-term working process of the test device, solid particles will gradually accumulate on the filter screen and finally block the filter screen, resulting in the failure of the drilling fluid to flow normally. At this time, the test device needs to interrupt the exploration task and be lifted up to the ground for cleaning , which will reduce work efficiency and greatly increase drilling costs

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