Coal bed methane continuous sand flushing pipe string and its sand flushing method

Abstract

The invention discloses a continuous coalbed methane sand clean-out pipe series and a sand clean-out method thereof. The sand clean-out pipe series comprise separation pipe columns which are hanged on wellheads in a setting mode and run down, a sand clean-out pipe column which runs down from the wellheads, a sand clean-out head which is mounted in front of the sand clean-out pipe column and close to a sand clean-out surface, and a blind plate type seal circulating device which is mounted in the middle of the sand clean-out pipe column, the upper end of the sand clean-out pipe column extends out the wellheads, the space between the sand clean-out pipe column and the wellheads is sealed through the seal device, and sand clean-out mediums are injected into the annular space between the sand clean-out pipe column and the separation pipe columns through inlets; the sand clean-out mediums are injected from the wellheads and pass through the annular space between the sand clean-out pipe column and the separation pipe columns at the upper end of the blind plate type seal circulating device, due to the blockage effect of a blind plate, the sand clean-out mediums can only run down, finally spray out from the sand clean-out head and return to the wellheads through the annular space between the separation pipe columns and completion pipe columns, and thus the effect that the single sand clean-out pipe column continuously works without pumping off is achieved.

Description

technical field [0001] The invention relates to a coal bed gas well sand washing technology, in particular to a coal bed gas continuous sand washing pipe string and a sand washing method thereof. Background technique [0002] At present, domestic coalbed methane wells are mostly completed with casing or screen pipes. During the mining process, coal ash enters the wellbore along with the coalbed methane and gradually accumulates, affecting gas production. Regular sand washing is required. The existing domestic sand washing technologies mainly include coiled tubing sand washing technology and conventional tubing sand washing technology. [0003] Coiled tubing is used for sand washing, the cost of equipment is high, and good economic benefits cannot be achieved, while for conventional oil tubing for sand washing, the sand washing medium is injected through the wellhead tubing, and the pump needs to be stopped for single connection, and the sand washing process is discontinuous....

AI Technical Summary

Problems solved by technology

[0003] Coiled tubing is used for sand washing, the cost of equipment is high, and good economic benefits cannot be achieved, while for conventional oil tubing for sand washing, the sand washing medium is injected through the wellhead tubing, and the pump needs to be stopped for single connection, and the sand washing process is discontinuous. At this time, the pulverized coal Falling back, prone to the risk of sand jams

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