1. S. [Perforación, Fluidos de perforación]
A survey in which the annular volume of the wellbore is mathematically calculated with a flowmeter and a marker. The drilling fluid in the hole is used as an analog to determine the amount of cement needed to circulate back to surface. It is run by pumping the marker down the drillstring, circulating it back up the annulus, and catching it where it exits the flow line. Using the circulation time, pump volume, hole size, fluid viscosity, and several other factors, the annular volume of cement is calculated. It can be run on any string to any depth. It can be run with partial circulation loss, but not with totally lost returns.