Patent ID: 8776609
Filing Date: 2014-07-15
Classification: E21B,G01B

Abstract:
1. A method for analyzing cement in the annulus of a well during a downhole operation, comprising: controlling internal pressure of a casing of the well; measuring internal pressure of the casing; measuring strain of the casing with a system comprising at least one string of interconnected sensors that is arranged such that the sensors are distributed along a length and the circumference of the casing, the measured strain being a function of internal pressure; and determining the quality of the cement as a function of strain of the casing and internal pressure, wherein determining the quality comprises determining the proportionality of strain of the casing to internal pressure so as to establish a line of proportionality; further comprising differentiating between the mechanical breakdown of cement and the initiation or propagation of a fracture in the formation, respectively, by identifying whether the strain of the casing deviates from the line of proportionality or moves up and back down the line of proportionality.