Effect of curing conditions on oilwell cement paste behaviour during leaching: Experimental and modelling approaches

Long-term durability of cement-based materials used in oil wells is a major concern for the oil and gas industry and the emerging industry of the carbon dioxide geological storage. Therefore, understanding of physico-chemical processes leading to cement paste degradation is of utmost importance. The aim of this study was twofold: the first one was to characterise chemical and physical properties of oilwell cement paste exposed to running brine, and the second one was to model these changes with a reactive transport model called HYTEC. Before leaching tests, two curing modes were tested. The results reported structural and chemical differences between the cement pastes observed after the two types of curing, leading to a different behaviour after a 3-month leaching test in brine at 80 °C. First simulations reproduce the main experimental results obtained after cement paste leaching.