Correlating variationsin chemical and nanoscale components of oil-field cements to hydration, water transport, and macroscopic flow characteristics

Cementing is a critical stage in any petroleum well construction project. Once a well has been drilled, a cement slurry is pumped around the annulus of the steel liner to provide an impermeable barrier between the well bore and the rock formation. The cement seal is necessary to ensure well stability and prevent contamination of subsurface water aquifers with hydrocarbons. Catastrophic failures in well integrity (such as occurred recently in the Gulf of Mexico) have been attributed to poor cement performance or incomplete removal of drilling fluid during placement. The significant time required to pump cement around a well is an additional complication, as the cement chemistry and nanostructure is constantly evolving. The macroscopic properties of the cement (rheology as a slurry; thickening time; permeability and compressive strength when hydrated) are controlled by the chemical formulation and particulate additives. However, there is presently incomplete understanding of the detailed relationship between the tuneable formulation parameters and the in-service performance. The aim of this project is to understand relationships governing the hierarchy of relevant length and time-scales using a multifaceted experimental approach.

Schlumberger is an oilfield services company with a global footprint. Activities at the Cambridge centre focus on the development of new science and technology for well construction, with an emphasis on well construction processes and automation. The facilities available for this proposed project include a suite of low field magnetic resonance instruments, Fourier transform Infra-red (FTIR) and X-ray fluorescence (XRF) spectrometers, conventional rheometers, and hydrodynamic flow systems. The project will be supervised by Dr Débora Campos de Faria (chemistry) and Dr Jonathan Mitchell (magnetic resonance). Support for aspects of the project related to high temperature / high pressure characterisation, fluid flow, and modelling / simulation will be provided by other scientists and engineers at Schlumberger Cambridge Research.