(597f) Viscosity of Hydrocarbons and Hydrocarbon Mixtures at Extreme Conditions

The production of petroleum from ultradeep formations beneath the deepwaters of the Gulf of Mexico is a challenging task that represents current domestic efforts to recover oil from formations that are increasing difficult to access.  The conditions in these formations are extreme, with exploration and productions projects occurring in formations where the temperatures approach 260 C (500F) and pressures can reach over 240 MPa (~35000 psi).  There are significant gaps in experimental density and viscosity databases for many constituents of petroleum at these conditions, particularly above 150 C and 20000 psi.  Therefore it is difficult to obtain accurate estimates of reserves and long-term predictions of oil and gas recovery rates.

The objective of this work is to provide precise pure-component and binary mixture viscosity values for various hydrocarbons at extreme conditions using a novel rolling ball viscometer.  Because fluid density is required for the determination of viscosity, we are using our group’s recent measurements of the density of the same hydrocarbons at extreme conditions.

The study has included n-hexadecane, n-octadecane, n-eicosane, n-octane, isooctane, cyclooctane, squalane and a propane-n-alkane binary mixture.  Results have been modeled using several models capable of estimating viscosity of multi-component mixtures of changing composition during reservoir simulation; including free volume theory, friction theory, and the Chung-Lee-Starling, Lorenz-Bray-Clark and Pederson corrleations.