The Study About The Influence Of Micro-Pore Structure Parameters Of Sandstone In Polymer Flooding Development

The reservoir pore structure means that space structures of pore and throat space,which include the size and distribution of pore, the connectivity between pore and throat, the geometry and heterogeneity of pore, the component and occurrence of the clay mineral in pore and so on,and they reflect the heterogeneity of reservoir. The pore structure parameters not only control migration and accumulation of oil but have major effect on production capacity and displacement efficiency and final recovery efficiency of the reservoir.The previous research demonstrated that there was preferable correlation between some pore structure and water flooding recovery, but there was not a report about the correlation between pore structure and polymer floodinging recovery. Actually pore structure has bigger effect on polymer floodinging than water floodinging because oil displacement mechanism of polymer floodinging is different from water flooding and polymer flooding has inaccessible pore structure and polymer solution has viscoelasticity and rheological property and adsorption captation effect on rock. So it is necessary to research the effect of microscopic pore structure on polymer floodinging displacement characteristics.This paper used the methods including normal mercury penetration, constant rate mercury penetration, cast thin analysis and electron microscope scanning to analysed the microscopic pore structure of Lasaxing oilfield ,and built the relationship between pore structure parameter and macro-parameter; it also analysed the pore structure divergence in different oil layer and different oilfield:â‘ The pore homogeneity in PI oil layer was the strongest in Sazhong area and the pore heterogeneity was the strongest in Xingnan area; the pore heterogeneity in Saertu oil layer became stronger from north to south;â‘¡In Lamadian oilfield, the micro-heterogeneity in PI oil layer was stronger than SII and SIII oil layer; and in Sazhong and Xingnan oil field micro-heterogeneity in SII and SIII oil layer was stronger than PI oil layer.â‘¢The average pore radius was bigger and the micro-heterogeneity was stronger in PI oil layer of Xingnan area.Incorporating physical modeling experiment result, it also analysed the quantitative effect of pore structure parameters on polymer flooding displacement characteristics and selected the principal factors; Using the methods of polynomial regression and artificial neural network, it built the relationship equation and forecasting model between principal factors and polymer flooding displacement characteristics and forecasted the polymer flooding recovery in Lasaxing oil filed.This thesis provided an utility method which could calculate the inaccessible pore volume which could establish the inaccessible pore volume of arbitray molecular polymer solution in arbitray permeability reservoir, and invented a polymer floodinging physical modeling method using tracer polymer solution which could watch the flow route of polymer solution in porous media.