Study On The Percolation Characteristics Of Unconventional Tight Oil Reservoir

In recent years,the advent of new technologies including horizontal wells,the volumetric fracturing and the factory-like operation have made tremendous progress in the domestic tight sandstone reservoir.However,the study of pore structure characteristics and oil displacement efficiency are critical questions to be addressed.This paper presents a comprehensive research about pore structure characteristics and water displacement efficiency through some theoretical approaches and a series of experiments,such as regression analysis method,grey incidence analysis,grey cluster analysis,mercury intrusion porosimetry,oil-water relative permeability experiment and water-oil displacement experiment.Based on mercury intrusion porosimetry,grey incidence analysis and grey cluster analysis,some conclusions can be drawn as following:As a part of pore structure characteristic parameters,structure coefficient has the best correlation with porosity and permeability.A new microscopic pore structure complex factor of porous media was defined;utilizing new porous media microscopic pore structure complex parameters,the microscopic pore structure complexity of porous media can be evaluated with the macroscopic parameters of porous media,Permeability and porosity.These parameters have a strong engineering significance.It has a good relationship with water breakthrough time for water flooding.In the study,a new factor and model are used to construct grey pore structure comprehensive factor and the grey pore structure comprehensive evaluation model.According to the results of the study of pore structure and the data of oil-water relative permeability experiment and water-oil displacement experiment,the study on water displacement efficiency can be achieved.Although many key factors including the injection volume,reservoir physical properties and pore structure characteristics embody a certain correlation with water displacement efficiency,all elements could not do clearly.In addition,comparing the grey pore structure comprehensive factor and the parameter calculated by the reciprocal of variation coefficient multiplying structure coefficient,the former has better correlation with water displacement efficiency.