Review of Evaluation Methods for Cement-Formation Interfacial Bonding Strength

Cement-formation interface integrity is an important factor affecting the cementing quality of oil and gas wells, which determines the zonal isolation performance for the lifetime of oil and gas wells. The interfacial bonding strength is an important index reflecting the integrity of the interface. Excellent bonding strength can reduce the formation of interfacial micro-gaps, prevent formation fluids channeling through annulus along the interface, avoid blowout and other safety accidents. At present, the evaluation results of laboratory simulation experiment on the interfacial bonding strength usually differ greatly from the field logging results, and it is difficult to reflect the real interface cementation. Therefore, how to evaluate the interfacial bonding strength objectively and reliably has become an important issue for researchers in recent years. In this paper, the research progress of cement-formation interfacial bonding strength evaluation methods is systematically reviewed focusing on evaluation parameters such as shear bonding strength, hydraulic bonding strength and tensile bonding strength. It can be seen that in the process of measurement, attention should be paid to how to simulate the actual downhole environment conditions, select the appropriate stress loading mode and loading angle, and reduce the measurement error. With the development of instrumental analysis technology, non-contact technology based on digital image correlation and in-situ visualization analysis technology based on micro-computed X-ray tomography have been widely used, which can achieve more accurate measurement of interfacial bonding strength, and become the development trend of future research.