Experimental Investigation on Cementing Integrity of Oil/Gas Wells

The integrity of cementing in oil and gas wells is vital for ensuring wellbore stability and preventing environmental contamination. However, the extreme conditions encountered during production and abandonment, such as the combined high pressure, temperature, and chemical exposure, pose significant challenges to the long-term performance of wellbore cement. This may lead to cracking, debonding and structural failure of cementing, ultimately causing leakage of gas. Existing research is mainly focused on analysing the potential parthway of leackage and some simplified experimental test for estimating the long-term behaviour of cementing. However, to accurately understand the whole life performance of cementing in Oil/Gas wells requires realistic reproduction of the in-situ environment for cement curing and testing the material properties such as permeability especially for the interface between cementing and rock formation rather than cementing itself. This study is therefore aimed to provide an innovative experimental analysis on quatntifying the cementing integirity in Oil/Gas wells by reproducing a model size of a section of rock-cementing section under the in-situ real environment. A seiries of experimental tests are then conducted to obtain the physical and mechanical performance for, in particular, the interface of the cement and rock. Whole life service condition is also considered and the long-term deterioration on the cementing and its interface with rock is quantitatively determined. The findings of this research are expected to contribute to the acucurate and comprehensive understanding of the whole life performance for cementing in Oil/Gas wells  and more resilient cementing solutions with broader implications for other subsurface engineering applications, including underground energy storage and low-carbon infrastructure.