Shirish Patil

Experimental investigation of the influence of nanoparticles on water-based mud

This study has investigated the influence of nanoparticles including nanoparticle concentration, size, and type on water-based mud (WBM) properties including rheology, filtration, and lubricity through experimental tests, while the influence of temperature and aging on these properties have been investigated. It has been found that adding SiO2 nanoparticles increase the plastic viscosity and decrease the yield points and gel strengths with the increase of nanoparticle concentration. At fixed 0.5 wt%, the plastic viscosity decreases with the increase of TiO2 nanoparticle size, but the influence of TiO2 nanoparticle size on yield points and gel strengths is not monotonous. In general, adding negative charged SiO2 nanoparticles reduce the yield points and gel strengths, while adding positively charged TiO2, Al2O3, and Fe3O4 nanoparticles increase yield points and gel strengths. Adding lower concentrations (<xa00.05 wt%) of SiO2 nanoparticles improved mud filtration and lubricity properties, but higher concentrations are adverse to these properties and adding 0.5 wt% TiO2, Al2O3 and Fe3O4 nanoparticles impaired these properties. Besides, it is found that there is no consistent influence of aging on mud properties and adding nanoparticles cannot improve aging resistance of mud. Although adding nanoparticles can significantly affect WBM properties, their influences are not consistency, depending on the integrated impact of the nanoparticle properties, such as surface electrical property, specific surface area, concentration, and size.

From declared asset retirement obligations to a decommissioning cost estimate for onshore crude oil fields in Nigeria

As in most mature crude oil producing regions, asset divestment has commenced in Nigeria. Decommissioning and associated environmental liabilities are expected to become important problems requiring attention. Public and government engagement on decommissioning will be ineffective without information on cost of decommissioning liabilities, which are held confidential by oil companies. This study demonstrates a method to determine generic aggregate cost of decommissioning liabilities for Nigeria onshore fields, using non-proprietary data from annual financial reports of operating companies in Nigeria. The results can be used as basis for negotiation with operators and to help government in preparation for decommissioning risk.