Mechanism of gas compressing polymer gel in porous media

Key words:  polymer gel  gas channeling  gas plug  porous medium  enhanced oil recovery

Abstract:

The mechanism of action of polymer gel oppressed by gas and brine respectively was analyzed based on the gel theory of saline washed porous media. The gas and liquid phase saturation space distribution curves in a porous medium which is saturated by polymer gel were calculated and contrasted. The application scope of saline washed porous media theoretical model was improved, and the effects of two residual gel gas produced on gas seepage after gas breakthrough were investigated. The results show that microscopic percolation capacity of salt water is stronger than gas in the gel, while microscopic percolation capacity of gas in porous medium is weak after gel plugging. Under the same condition, the gas under the microscopic percolation state in invaded area is less. Gas needs a long time accumulation to destruct the three-dimensional network structure gel gradually. Therefore, before the gel breaking, the validity period of gas plugged by gel intensely will be longer compared with that of saline. The model based on the gel theory in porous media washed by saline has a general applicability. The gel is extruded by fluid and the body structure is destructed, which is an universality when polymer gel resists foreign fluid in order not to be undermined in porous media. It has nothing to do with the type of fluid and polymer gel system. The model can be used to predict the plugging performance of various gel system in different environments.