Automatic Rod-Pump Shut-Off
Problem: A small independent oil producer operates a shallow, 40-well oil field in an area subject to extremely cold winters. The operator’s poly flowlines would freeze and rupture in the cold weather. Increased paraffin deposition also contributed to this problem. The flowline ruptures resulted in contaminated soil that had to be cleaned up under Statewide Rule 91. Also, to prevent rupture of the flowlines, the rod-pumps had to be shut down when freezing weather was predicted, resulting in loss of production and revenue.
Solution: The operator designed and installed an automatic pump shut-off system on each well. A low cost system was designed (about $75 per well, including parts and labor). The total investment for installing the devices on each of the 40 wells was about $3,000. The automatic shut-off system was made using an automotive brake light switch (pressure switch), copper tubing, hydraulic fluid and a simple relay switch. The circuit was designed such that the pump must be manually restarted after the cause of shut off is determined.
Benefits: Since installation of the automatic shut-off systems, the operator has not experienced a single flowline rupture. As a result, the associated problems, such as soil cleanups, and loss of production and revenue, have been eliminated. The operator did not provided the specific economics for this project. However, it is clearly cost effective. The savings from reduced soil cleanups and increased revenue from more efficient production would easily recover the nominal capital investment.