Deformation and damage of cement sheath in gas storage wells under cyclic loading

The mechanical damage and failure of cement sheaths in gas storage wells under cyclic loading have been studied extensively. However, because the test device cannot restore wellbore condition, most studies theoretical or regular experimental. If load-bearing mode stress environment a differ from those wellbore, then modes will deviate what occurs actual wellbore. Therefore, it is necessary to explore method that restores condition design simulation reveals deformation sheath. In this study, development laws microannulus microcracks sheath were by triaxial loading, low-field nuclear magnetic resonance imaging, scanning electron microscopy. A evaluate integrity was developed. equivalence proposed, based on principle stresses at first second interfaces are equal This used material, size, experimental conditions simulate load-deformation law well. mechanism investigated using results computed tomography. Micropores increased continuously loading. Damage accumulated, causing strength as period increased. Plastic occurred but interfacial peeling did not. reason compressive during unloading, interface between outer wall not damaged. study provides new for studying complex conditions.