Single-well drainage and production device and method for double-layer superposed CBM-bearing system

摘要

#$%^&*AU2019427989A120201105.pdf#####ABSTRACT Disclosed in the present invention is a single-well drainage and production device and method for a double-layer superposed coalbed methane (CBM)-bearing system, wherein the device comprises an upper CBM-bearing system extraction end, a lower 5 CBM-bearing system extraction end, and a surface drive unit. An outer casing is provided in a CBM well, and the upper CBM-bearing system extraction end and the lower CBM-bearing system extraction end are both provided inside the outer casing. An inner casing is fitted along an inner wall of the outer casing at one side. A pump hanger system is disposed separately in the inner casing and in an annulus between 10 the inner casing and the outer casing, and the two pump hanger systems are both connected to the surface drive unit. The inner casing and its corresponding pump hanger system together form the lower CBM-bearing system extraction end, and the annulus between the inner casing and the outer casing and its corresponding pump hanger system together form the upper CBM-bearing system extraction end. The 15 present invention can form two independent drainage and production spaces in a single wellbore, avoiding inter-system interference during drainage and production, and further reducing the cost. [FIGURE 1