PRESSURE EQUALIZING A BALL VALVE THROUGH AN UPPER SEAL BYPASS

摘要

A pressure equalizing system allows flow past an upper seal on a movable member downhole that in turn allows pressure to be delivered from uphole into what had previously been an isolated low pressure zone. The pressure differential across the member is equalized before attempting to move the member into another position. In the preferred embodiment the member is a ball in a ball valve for subterranean use.