With more and more emphasis on reducing expenses for beam units, most operators are examining all areas to try tocut costs. One of the biggest costs in beam unit operations is the associated electrical charges.
Examining the pumping units to determine and adjust to the optimum counterbalance will reduce the electrical bill. Several fields have been checked with a PC software program, which allows the operator to determine how far out of balance the units are and what it will take to properly balance them. Properly balanced pumping units will result in savings both in kilowatt hours demand and also in consumption, reducing the electrical costs.
Examples from several fields are discussed, including the actual power costs and the reduction in expenses that occurred.
The first approach in determining if your wells require rebalancing or motor downsizing is to conduct a survey of the field. When the POWER software first became available, it was run on several individual wells to determine if either the unit was out of balance problem or if the motor was too large. This micro approach does not address any real potential cost savings unless a particular unit is way out of balance. The POWER program requires actual well data be gathered. The two probes are connected to the incoming electrical lines during two strokes of the pumping unit to gather information for interpretation. The actual time to measure these values is small, but all of the data is necessary to properly interpret the condition of the well. If the well is operated with a pump-off controller, you must determine the condition of the well for the majority of the run time, since it may vary widely from first coming on to just before pump-off.
The first small field surveyed consisted of 17 producing wells in the Waddell field near Crane, Texas. Production depths range from 8700' to 9700' and all wells wereequipped with beam pump units. This particular field also has a history of high gas-oil ratios, which has caused some lifting problems in the past. Incomplete pump fillage is not uncommon from this area, since in some cases, the tubing intake is located above the perforations.
Direction of pumping unit rotation was also checked with respect to which cost less electrically to run. In some cases changing the direction of rotation did help reduce the electrical costs and the rotation was permanently changed to take advantage of the savings. Some other work is being done right now to try to determine which tap on a high-slip motor is best and does direction of rotation make a difference in operations. Preliminary indications are to operate in the high-torque mode and rotate counterclockwise, unless rod overloading becomes a problem.
Table I lists the wells in the Waddell area and the resultant data gathered from the survey of the field. A meeting was held with the field personnel to present the results and the recommend moving counterbalance weights on 12 of the 17 wells.