Lined tubing performance in CSG wells operated in Australia

Abstract

One of the major challenges with progressive cavity pump (PCP) applications in Australia is the production of highly concentrated solids. Large volumes of solids entering the production string cause both high torque issues and holes in tubing, resulting in lost production and the need for intervention with a flush-by unit or service rig. On account of these issues, it is reported that up to 40% of PCPs in the Australian coal seam gas (CSG) fields can be down at any given time. Coho Resources has introduced lined tubing as an engineered solution. The proprietary lining the tubing has a lower friction factor compared with conventional steel tubing, resulting in lower operational torque and reduced operating costs. The added lubricity from the lower friction coefficient in lined tubing allows solids to flow more freely to surface where they are captured and discarded from the system. Lined tubing allows producing companies to realise bottom-line operational savings in several ways. The largest of course is minimal downtime and reduced well service costs due to the elimination of our previous tubing related problems. With reduced work over costs, savings become visible very quickly. Rig costs, bottom hole pump, tubing and sucker rod replacement costs are all reduced. Application of lined tubing in CSG wells in Australia results in: • 15–25% less torque on the drive system, • An 70% increase in run times between workovers (lined tubing versus un-lined tubing), and • Compatibility with existing field equipment and handling methods.