Numerical and Experimental study of the effect of downhole stresses cement bonding
End: Completed/ To be continued
As justified by reported incidents, the role of wellbore cement being a competent barrier for up-hole hydrocarbon flow is questionable. In particular, it is not clear whether the integrity of the bond and seal between the cement and formation or cement and steel-casing is sustained throughout the lifecycle of well operations and beyond.
The cement/casing and cement/rock interface of a cemented annulus is a brittle material-composite. During well operations the bond is subject to static and dynamic stress loads. The risk of bond failure depends on the load frequency, its magnitude, and intrinsic properties of the bond between the cement and casing, as well as the cement and rock.
This research project proposes to apply a certain low number of stress cycles on a cement/casing and cement/rock annular composite to evaluate the low cycle fatigue strength of the bond. Hence, innovative laboratory fatigue testing concepts will be developed in parallel with cutting edge testing apparatus. This will allow the application of static and dynamic axial loads (compression/tension) on an annular cement/casing and cement/rock bond. The experimental results will be compared to finite element/finite differences modeling results for validation.