Novel Approach to Identify Sand and Viscous Oil Problems Through the Analysis of Dynamometer Cards and Field Practices

Problems due to the solids and viscous oil are difficult to predict in the dynamometer cards. An innovative approach is devised to identify solids and viscous oil problems, based on the interpretation of dynamometer card analysis and troubleshooting practices implemented at the field scale. Sand or wax incursion in the subsurface pump causes the pump screen or perforation to choke, resulting in no communication of the reservoir with the tubing. It can cause no free fall of polished rod and sucker rod string getting stuck up. Heavy viscous reservoir fluid shows the standing valve, traveling valve, or both pump seats getting choked. The drag force creates an extra differential force between the plunger and the pump, showing the case of the sucker rod unscrewing or parted as pump seats get choked up in the dynamometer card. Casing head pressure, pump hydraulics, and the shape of the dynamometer card are critical parameters in differentiating between the fluid pound, gas interference, and blocked pump intake. The plunger stops before opening the traveling valve in case of pump intake is blocked, or the spiky and curvy loads in the dynamometer card due to solids-related problems. During the circulation job, higher pumping pressure taken by the pumping unit ascertains the solids incursion. Viscosity is an important property that determines load distribution on the rod string. The drag force causes the dynamometer card to stretch, but practically the rod is unscrewed or parted. Post-rod string makeup well started producing liquid. It has revived non-flowing wells and prevented production downtime. This unique approach will benefit the operators in analyzing the sand, solids, and viscosity-related problems and troubleshooting these failures of rod-pumped wells. Oil gain has been observed in rod-pumped wells based on this systematic approach.