Nano-enabled Sustainable Cement Sheath Behind Casings

Well cementing is an important operation during oil well drilling. The cement sheath must maintain well integrity behind the casing throughout the life of the well (20-30 years). Despite recent technological advancement with elastomers, polymers, fibres a nd reactive components, including self-healing micro-fissures, the cement sheath is not able to deliver an acceptable long-term solution for todays demanding drilling environment. Shrinking of the hardening cement creates a suction pressure. Poor displa sement creates micro annuli and poor bonding of the cement to its surroundings. Harsh downhole conditions, such as temperature and pressure fluctuations impose persistent stresses on the cement sheath. Development of small micro-annuli and micro-crack all ow for fluid and gas migration. To cope with the fluid and gas migration problem on short and long term, we propose to apply swellable and elastic nanoparticles in the well cement in order to improve cement sealing and hence keep well integrity. Five di fferent state-of-the-art laboratories, NTNU NanoLab, Nanomechanical Lab, Concrete Lab, Drilling Fluid Lab and Heavy Duty Petroleum Lab, all situatied at two departments at NTNU, will be used to perform the comprehensive experimental work in the project. C omputational simulations will be carried out to complement the experimental development of nanoparticles. Atomistic simulation, such as molecular dynamics, is a powerful tool to evaluate and predict material properties from its atomic structure. The tota l package of renewed thinking of the cement sheath's fate through fundamental understanding, modeling and experimental investigation will lead to a sloution in the form of a long lasting cement sheath behind the casing.