Simulation Experiments on Oil Non-Darcy Flow in Low Permeability Sand Reservoirs

Kong Xu
China University of Petroleum, Department of Resources and Information Changping, Beijing P.R.China; [email protected]

This investigation took Putaohua low permeability reservoir of Gulong Sag as the study area. Applied with one-dimensional physical modeling experiments of oil/gas migration, the non-Darcy flow in oil migration, actuating pressure gradient, affecting factors in the process of oil charging and growth process of oil saturation were studied, and the conclusions were as follows:

(1) The non-Darcy flow characteristic with actuating pressure gradient displayed obviously in the process of oil charging (oil displacing water) in low permeability reservoirs. The flow curve was influenced by the combination effect of porous media, fluid viscosity, fluid-porous media interaction and driving pressure. The smaller pore throat of rock, the smaller permeability quotiety of rock and the larger the viscosity of fluid was, the more obviously the non-Darcy characteristic manifested. The non-Darcy flow characteristic displayed different flow regime under the condition of different pressure gradient. Accorded to the relationship between displacing pressure gradient and apparent fluidity under the conditions of different flow regime, the judgement chart of flow regime in the process of oil migration in low permeability sandstone was established.

(2)The growth process of oil saturation was divided into three stages: growing fast, growing slowly and stable. The ultimate oil saturation of samples is usually between 35%-60%. Accorded to the relationship between displacing pressure gradient and apparent fluidity under the conditions of different oil saturation, the judgement chart of oil saturation in low permeability sandstone was produced.

AAPG Search and Discovery Article #90083 © 2008 AAPG Foundation Grants in Aid