RIASSUNTO
Summary
A novel hydraulically powered, self-reciprocating valve pump (SRVP) was piloted in a western Colorado gas well for deliquification operations. The objective was to pump liquids from a deep gas well and later retrieve and redeploy the SRVP without a workover rig. This paper will describe the SRVP technology, areas of applicability, and pilot program, including the completion design, deployment/retrieval workovers, performance, teardowns, learnings, and future plans.
Gas-production wells tend to load up with produced or condensed liquids that create an impediment to flow and reduce or stop gas production. Pumps are typically used when the reservoir pressure is too low for less-intrusive artificial-lift (AL) methods or when significant amounts of liquid must be removed. Pumps can suffer from reliability issues and considerable installation/deployment costs because a workover rig is typically required for intervention. Unfavorable producing conditions and tortuous wellbore trajectories tend to further decrease run lives. These issues can make economical hydrocarbon production impossible. The SRVP was developed to overcome these challenges.
The SRVP is installed downhole inside a concentric tubing string, and is powered by injecting a high-pressure liquid. The injected (power) fluid causes the SRVP to reciprocate, driving a piston pump to produce formation fluids and to power fluid back to the surface up the concentric-string/production-tubing annulus. The removal of the produced fluids decreases the backpressure on the formation, enabling gas production up the casing. Because there is no mechanical linkage to the surface for pump operation, the SRVP can be deployed in highly deviated and/or small-diameter wells with which standard AL methods would struggle. In addition, the SRVP is designed to be pumped into and out of the well after initial installation, greatly reducing deployment costs.
Three industry-first SRVPs were installed consecutively in a concentric flush-joint tubing string, and were powered with a compact surface pumping unit. The SRVP proved the ability to lift 20 to 40 BFPD net liquids up the concentric-string/production-tubing annulus from more than a 12,000-ft vertical depth while gas was produced up the casing. The SRVP was retrieved and redeployed several times either hydraulically and/or with slickline (SL). System design, operation, and performance were continuously improved through the duration of the pilot program. Run life steadily increased to more than 50 days with the third installation.