A New Technology/Laboratory Set-Up And Mathematical Method To Determine Pore Throat Size Distribution Of A Natural Rock
Petroleum Engineering Honours Degree, 2011
University of Adelaide
Suspension, colloidal and emulsion flow in rocks and the subsequent particle capture due to size exclusion may strongly affect reservoir and well behaviour. Particle transport in suspension flow occurs during sea or produced water injection, fines migration and production and drilling fluid invasion into hydrocarbon bearing zones.
Previous methods have been developed to determine the pore size distribution using particle suspension coreflood tests where a colloidal suspension is flowed through an engineered porous media with a known grain size distribution and outlet particle concentrations are measured.
Continuing on from this work, a low retention filtration model is developed and tested using a new laboratory set-up for the short term injection of mono-sized suspensions in to engineered porous media. The stochastic micro scale equations for size exclusion colloidal transport in porous media are derived. The proposed model accounts for the following new features: the accessible flux in the expression for capture rate, the increase of inlet concentration due to the injected particles entering only the accessible area and the dilution of effluent accessible flux in the overall flux of the produced suspension.
Many improvements have been made to the experimental set-up and procedures to enhance the accuracy and repeatability of the colloid injection tests. These include the implementation of a dualpump syringe system to deliver continuous pulse-less flow of fluid to the engineered porous medium, the packing of the column is performed during sonification to ensure uniform dense rhombohedral packing and the outlet sampling intervals have been revised to gain a clearer view of breakthrough and stabilisation of outlet concentration curves.
Good agreement was observed between the experimental results and the proposed model. The proposed model fits better to the experimental data than the previous population balance model for suspension transport in porous media. The modifications in the present model, compared to the classical deep bed filtration model, lead to the better description of size exclusion particulate transport and particle capture in porous media.