A.J. Mansure, Sandia National Laboratories, A.L. Podio & Jamie Gomez, University of Texas at Austin, & Benny J. Williams & Mark Mahoney, Harbison-Fischer
A full-scale, transparent, laboratory, instrumented sucker-rod pump has been constructed to aid in designing a downhole, instrumented pump. The laboratory pump has demonstrated that key to the understanding of sucker-rod pumping is compression-chamber pressure. Laboratory data will be used to demonstrate real-time analysis techniques that will be used with the downhole, instrumented pump to differentiate between a gas-locked or a pumped-off well using compression-chamber pressure. For a gas-locked well, the pressure is symmetric between the upstroke and downstroke; where as, for a pumped-off well there are high and low pressure plateaus when the valves are open. A method will be demonstrated to determine sucker-rod pump fillage by cross plotting (Pressure)-1/r versus stroke (g is the heat capacity ratio). The intercept of the compression line and stroke gives pump tillage. Theintersection of decompression and discharge pressure can be used to determine the residual gas trapped between the standing and traveling valves at the end of the downstroke.