PETROGRAPHIC IMAGE ANALYSIS FOR PREDICTION OF PETROPHYSICAL PROPERTIES AND WATERFLOOD DISPLACEMENT EFFICIENCY: SOME MISSING LINKS

摘要

PIA is a method used to quantify the two dimensional aspects of pore geometry comprehensively and rapidly and,using statistical techniques,to identify those pore types or attributes which are the best predictors of petrophysical properties of interest.Pore types,once identified,are used to predict petrophysical properties where core test data are not available.PIA provides the most effective method available for understanding how specific rockpore attributes affect fluid flow and displacement processes.PIA also has applications in predicting petrophysical properties of interest in samples too small for conventional core testing,for example drill cuttings or core rubble.This presentation is restricted to a review of the applications of PIA to prediction of porosity,permeability,drainage capillary pressure,initial water saturation(Swi)and waterflood residual oil saturation(Sor).Throat sizes cannot be identified or measured on 2-d surfaces through porous rocks and,since permeability and drainage capillary pressure are primarily affected by throat size,it is surprising that these properties can be successfully estimated by PIA.Part of the explanation rests with the pervasive correlation between pore sizes and connecting throat sizes in porous rocks.The reasons for these relationships are not yet understood.PIA results indicate that specific size and shape characteristics of pore types have strong effects on permeability,drainage capillary pressure,Swi and Sor and that the necessary information to predict these properties is contained on 2-d sections of reservoir rock.