Surface Equipment – Orifice Meter
Permitting a wellhead meter to read high robs your employer. The royalty and severance tax payments made by the lease operator are based on the meter readings. Pulsations in the meter run (such as those induced by wellhead reciprocating compressors) will invaribly cause the meter to read high. Occasionally, field personnel install a smaller orifice plate in the meter run and forget to note this fact on the flow chart. This greatly increases the recorded gas flow rate. Incidentally, most meter runs are equipped with facilities to permit change of the orifice plate without interrupting the flow of gas through the meter. This is called a “Senior Meter Run”.