(2014022) TROUBLESHOOT ROD PUMPED WELLS USING TUBING FLUID LEVEL SHOTS
If no pump action, a recommended practice is to shoot a fluid level down the casing annulus and also shoot a fluid level down the tubing. Distance down the tubing is determined by using the average acoustic velocity obtained from the casing shot. DO NOT use the tubing average joint length to interpret the down tubing fluid level, because inside the tubing rod couplings are spaced at the length of the sucker rods.
Analysis of the acquired data can determine such things as: If there is a hole in the tubing. Additional tubing back-pressure maybe required if tubing liquid was unloaded by significant amount of gas produced up the tubing. Tubing pressure buildup measurement determines the amount of gas flowing up the tubing, tubing percent liquid, and the effectiveness of the dowhole gas separation. Difficult to interpret tubing shots may indicate that the well has “paraffined-up”. Tubing shots acquired at uniform time intervals can show ineffective pump operation, where “pumping up” the tubing occurs too slowly. Down tubing fluid levels are effective tools when troubleshooting shooting a shut-in sucker rod pumped well suspected of having no pump action.