ESTIMATE OF COMPACTION WITH BOREHOLE GRAVITY MEASUREMENTS

摘要

A method of estimating compaction of a subterranean formation (12) with gravity measurements. The free air gradient at surface (S) is measured and compared with gravity measured in a borehole (10) that intersects the formation (12). At a later point in time, values for gravity are re-measured, differences between the measured values at the initial point in time, and the later point in time are estimated. The differences are used to estimate the compaction. A gravimeter (20) can be used for measuring gravity, markers (221,222) in the formation (12) can be used in conjunction with the gravimeter (20).