Mechanical behavior of well cement cured in saline water: an application to oil and gas wells

Abstract

Geo sequestration of carbon dioxide (CO2) has been found to be one of the best solutions to reduce greenhouse effect. The injection wells and well cement plays a vital role in well integrity. The loss of well integrity is the major issued and that may be explained by the degradation of cement as well as the down hole curing conditions. Salinity is an important factor that varies from 0-30% NaCl depending on the geological location. Therefore, aim of this research is to analyze the mechanical behaviour of cement cured in different salinity levels with various curing periods. Testing such as uniaxial compressive strength (UCS) test, X-Ray Diffraction (XRD) and Scanning Electron Microscopical (SEM) observation were conducted to obtain the behavior of the cement cured in different conditions. Based on the outcome, it was observed that the strength of the OPC based well cement decreases with increasing salinity levels and with ageing in time.