DETERMINATION OF FRACTURE CLOSURE PRESSURE

摘要

A method of determining the minimum in-situ stress of an underground formation penetrated by a well. The method includes injecting a fluid at a certain rate into the formation to produce fractures in the formation, backflowing the injected fluid from the well at a rate less than the injection rate, and measuring the well fluid pressure decrease during the backflow to establish the pressure at which the fractures close.