NEW CLASS OF METER SOLVES OLD PROBLEM IMPACTING WELL TEST ACCURACY

For the first time in a BP-operated asset, the impact of entrained gas in the liquid outlet line of a well test separator is quantified for the purpose of correcting gross fluid volumes. This paper describes the results of deploying a SONAR-based, clamp-on gas volume fraction (GVF) meter at a BP-operated test facility in Greater Prudhoe Bay.

In this particular test facility a coriolis meter is used to measure water cut and gross rate of the oil/water mixture. It was confirmed that discrepancies in allocation factors and individual net oil measurements, especially in cold flowing high viscous crudes, were due in part to unrecognized gas carry-under in the liquid outlet. Measured GVF associated with wells flowing less viscous crude (26 API) ranged from 0 - .6%, whereas the GVF of flowing viscous crude (18 API) was between 3 – 5% at normal set point increasing to >20% at reduced separator levels.

The additional secondary phase measurement enables BP to now report real time corrected densities and volumes using a proprietary method which is the subject of a future paper. In addition to viscous crude, we believe that application of this technology to smaller, somewhat under-sized separators with less stable operations will result in even more value to BP.