Reducing Water Cut in Oil Well Production by Self-healing Cement Sheath

Well construction is a complex process that requires meticulous attention at every stage, and well casing with subsequent cementing is no exception. The future efficiency and trouble-free operation of a well are contingent upon the quality of the cementing job. Therefore, effective wellbore preparation and the application of advanced cementing materials are of paramount importance. This paper presents laboratory study results evaluating the efficacy of an integrated approach developed by the authors. This approach involves preparing the wellbore for cementing using a system of spacer fluids tailored to the specific geological, mining, and technological conditions of drilling operations, followed by placement of a self-healing cement slurry into the annulus. This slurry can autonomously repair damage to the cement sheath integrity caused by various mechanical loads incurred during well construction, development, production, and enhanced oil recovery (EOR) operations. The methods for assessing the effectiveness of this integrated approach, utilizing newly developed procedures and laboratory setups, are also described. The developed spacer fluid system enables a 281.5% increase in cement-to-casing bond strength under laboratory conditions compared to conventional spacer fluids. Furthermore, the proposed self-healing cement can restrict the flow of mineralized formation water through 150 μm channels.