Comparison experiment on steel and non-steel slotted screen pipes used in coalbed methane wells

To reduce the current high completion cost for steel slotted screen pipes in coalbed methane wells and to develop low-intensity non-metal completion pipes to perform low-cost completion, this paper adopts electric survey to measure the collapsing strength and bending strength of J55 steel screen pipe and PVC non-metal screen pipe, and makes a comparative analysis of the effect of slot width and slot density on the strength of both kinds of screen pipes. The research results indicate that: the collapse of steel screen pipes mainly results from stiffness reduction or radial unstableness, showing the whole pipe deformation or the slot becoming wide or narrow at the internal or external wall along the short axis, accompanied with the tearing at the slot end-point; while the PVC screen damage mainly results from the material itself. For both steel and PVC screen pipes, the pipeʹs collapsing/bending strength declines with increase of the slot width and density, but the PVC screen pipes do not show such an obvious trend, making it possible to apply wider and denser slots on PVC pipes to increase the passing area.