Method for discontinuously acquiring underground pressure pulse of inflatable bored well

Abstract

The invention discloses a method for discontinuously acquiring underground pressure pulse of an inflatable bored well, which not only can acquire underground pressure pulse, but also can lead a downhole to be in an underbalance state. The method comprises the steps as follows: A, gradually increasing aeration quantity under no change of liquid injection quantity, wherein no pressure pulse feedback signals exist underground, the maximum gas holdup rate under the conditions is of a critical gas holdup upper limit; B, switching on a release valve, stopping gas ejection and injecting drilling fluid when detection equipment can not receive the signals, calculating reasonable gas stop time, and if the limit gas stop time within the maximum gas holdup rate range allowed of an instrument ensures the underground underbalance, acquiring underground pulse signals, otherwise, replacing measurement while drilling equipment with a higher gas holdup rate threshold value; and after the detection equipment receives the pulse signals, switching off the release valve, and ejecting the gas by equal gas ejection quantity at the last gas stop moment. By adopting the steps, the underground parameters can be accurately acquired, the drilling efficiency can be improved, and safety and fast well drilling on the guiding site can be achieved.

Description

technical field [0001] The invention relates to a method for obtaining downhole pressure pulses in pneumatic drilling construction, in particular to a method for discontinuously obtaining downhole pressure pulses for pneumatic drilling, which provides a basis for obtaining measurement-while-drilling signals and safe directional drilling. Background technique [0002] With the continuous development and utilization of various types of oil and gas resources, people pay more and more attention to the exploration and development of low pressure and low permeability oil and gas fields, so the underbalanced drilling technology has been developed unprecedentedly. Pneumatic drilling is the most economical and applicable method in underbalanced drilling. It is a method of injecting a certain amount of compressible gas (mainly air and nitrogen) into the drilling fluid as a circulating medium through an air compressor during the drilling process. The technology reduces the equivalent d...

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Problems solved by technology

[0003] In order to solve the problem that the ground detection equipment cannot receive pulse signals in the case of high gas holdup inside the drill pipe, the present invention provides a method for discontinuously obtaining downhole pressure pulses of inflatable dri

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