Mechanical, rheological and microstructural properties of saudi type g cement slurry with silica flour used in saudi oil field under HTHP conditions

With the continued growth of petroleum demand, the oil and gas companies are searching in new or unexplored areas. The search is getting extreme in terms of depth, temperature and pressure. In deeper wells, high temperature and pressure and post cementing operations put extreme stresses on the cement sheath and affect the integrity of the cement. In such conditions, the design of cement slurry is very critical and it must possess properties which ensure the durability and long term integrity of cement sheath. The purpose of this study is to evaluate the physical properties of Saudi cement class G with silica flour and admixed with different additives such as fluid loss agent, retarder, expanding agent and friction reducing agent under high temperature and pressure conditions. In this paper, we present the results of experimental investigations conducted on class G cement slurry without additives, as a basis, and cement slurry with additives and silica flour. Free water separation, rheological properties, compressive strength, density, scanning electron microscope (SEM), X-Ray diffraction (XRD), porosity and permeability tests were conducted with and without additives at both room and HTHP conditions.