A New Laboratory And Mathematical Method To Determine Pore Size Distribution Using Micro Models
Engineering Honours Degree, 2010
University of Adelaide
The transport and resulting deposition of colloidal particles within petroleum systems often leads to permeability declines and hence the decreased permeability of reservoirs. The transport of particle suspensions in oil reservoirs occurs during sea or produced water injection, produced water disposal in aquifers, drilling fluid invasion, fines migration during heavy oil production and during sand production control by gravel packs and sand screens. The determination of the pore throat size distribution is an essential component for the planning and design of the above mentioned petroleum processes.
Currently, two main methods are employed by industry to determine the pore throat size distribution of porous media. Mercury porosimetry fails to account for small pore throat concentrations due to the maximum pressure limitation and is incompatible for deformable or fragile porous samples. Challenge testing of filter media is limited by its inability to determine a complete pore size distribution. The limitations of the current methods result in the need for the development of an alternative technology capable of determining the complete pore throat size distribution.
A method is proposed by which the pore throat size distribution will be determined using particle suspension coreflood tests. The method involves flowing a suspension of particles with a known size distribution and concentration through porous media and measuring the stabilised breakthrough particle concentration and distribution when only straining effects occur.
Monte Carlo simulation has been used to predict the pore throat size distribution from a measured grain size distribution based on Descartes’ theorem. An extension of the parallel tube model for suspension flow in porous media that assumes equilateral triangular shaped pore throats was used to predict the pore throat size distribution. Good agreement was observed between the experimental data and the predicted pore throat size.