Concentric double pipe column reverse circulation continuous coal dust washing system well head device

Abstract

The invention discloses a concentric double pipe column reverse circulation continuous coal dust washing system well head device. The device comprises a moving inner pipe device, an outer pipe sealing device, a quick-change connector, an O-shaped sealing ring and a bolt, wherein an inner pipe connector I, a moving connector, an inner pipe I, a connecting end cap, an inner pie and an inner pipe connector form the moving inner pipe device; and an outer pipe connector I, an outer pipe I, a top base, a moving sealing pipe, an outer pipe, an outer pipe connector and a spring form the outer pipe sealing device. The device is characterized in that a coal dust washing device can move longitudinally along with an elevator, so that coal dust can be washed while tubular columns are lowered; the outer pipe sealing device can axially move along with the moving inner pipe device, and inner and outer oil pipes can be successively connected through the relative movement between the outer pipe sealing device and the moving inner pipe device; and the moving sealing pipe moves longitudinally relative to the outer pipe, so as to change flow directions of power fluid and returning fluid through movement, and ensure that the power fluid and the returning fluid flow in respective flow channels. The device has a novel structure, is convenient to operate, can realize the connection of concentric double pipe columns at the state that a pump is not stopped, and improves the efficiency of the existing workover treatment.

Description

Technical field: [0001] The invention relates to a wellhead device used in a workover operation system for a coal bed gas well and a low-pressure leakage oil well, belonging to the workover operation technical device category. Background technique: [0002] In the process of drainage and gas recovery of coalbed methane wells, solid particles such as coal powder, coal coke, and mud sand will inevitably be produced. Due to the unreasonable drainage system and insufficient drainage, these solid particles cannot be discharged from the wellbore with the well fluid in time, and will settle down at the bottom of the well, which will cause phenomena such as buried pumps and pump jams, resulting in suspension of drainage. In order to maintain continuous drainage , workover operations must be carried out. At present, coalbed methane drainage sites mainly use sand washing and mechanical fishing to remove coal powder from the bottom of the well. The former has great damage to storage, ...

AI Technical Summary

Problems solved by technology

Due to the unreasonable drainage system and insufficient drainage, these solid particles cannot be discharged from the wellbore with the well fluid in time, and they will deposit at the bottom of the well, causing phenomena such as buried pumps and pump jams, resulting in suspension of drainage. In order to maintain continuous drainage , must carry out workover work

At present, coalbed methane extraction sites mainly use sand washing and mechanical extraction of coal powder to remove coal powder from the bottom of the well. The former has great damage to storage, while the latter has low operating efficiency and cannot meet the needs of efficient coalbed methane extraction.

In addition, due to the low bottom hole pressure of coalbed methane wells, the use of conventional hydraulic flushing to repair wells will cause serious loss of power fluid, damage the coal seam structure, and affect the recovery of production capacity of coalbed methane wells

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