PORE GEOMETRY AND TRANSPORT PROPERTIES OF RESERVOIR ROCKS: APPLICATION OF LASER SCANNING CONFOCAL MICROSCOPY

UNDERSTANDING OF THE PHYSICS OF FLUID FLOW THROUGH SEDIMENTARY ROCK IS FUNDAMENTAL TO THE PETROLEUM INDUSTRY. ALTHOUGH THE TRANSPORT PROPERTIES (PERMEABILITY AND CONNECTIVITY) ARE DIRECTLY RELATED TO THE POROSITY, COMPLEXITY ARISES BECAUSE THEY DEPEND CRITICALLY ON THE GEOMETRY OF THE PORE SPACE. THE QUANTITATIVE DESCRIPTION OF THE PORE STRUCTURE IS THUS CRITICAL TO EVALUATE AND MOTIVATE THEORETICAL MODELS FOR THE TRANSPORT PROPERTIES OF POROUS ROCKS. BECAUSE THE COORDINATION (I.E., CONNECTIVITY) OF THE PORE SPACE IS CRITICAL TO THE MACROSCOPIC TRANSPORT PROPERTIES, ONLY LIMITED INFORMATION MAY BE OBTAINED USING CONVENTIONAL TWO-DIMENSIONAL IMAGING TECHNIQUES. IN THIS PROJECT, A NEW TECHNOLOGY, LASER SCANNING CONFOCAL MICROSCOPY (LSCM), IS BEING APPLIED TO THE STUDY OF THE PORE GEOMETRY OF SEDIMENTARY ROCKS. THREE-DIMENSIONAL IMAGING IS POSSIBLE BECAUSE LSCM CAN "SLICE" THIN OPTICAL SECTIONS OF THICK SPECIMENS WITH REMARKABLY HIGH RESOLUTION. IN THE PHASE I RESEARCH, THE THREE-DIMENSIONAL PORE GEOMETRY OF REPRESENTATIVE RESERVOIR ROCKS IS BEING CHARACTERIZED IN TERMS OF COORDINATION NUMBER, PORE DISTRIBUTION (E.G., NODAL PORES, CRACKS, AND TUBES), PORE SIZE, CRACK LENGTH AND WIDTH, ANISOTROPY, ETC. LABORATORY MEASUREMENTS OF THE PRESSURE DEPENDENCE OF PERMEABILITY AND RESISTIVITY WILL COMPLEMENT THE QUANTITATIVE MICROSTRUCTURAL ANALYSIS. BECAUSE FLUID FLOW IN SEDIMENTARY ROCKS IS CONTROLLED BY SHEET-LIKE "THROATS" (I.E., CRACKS) AT TWO-GRAIN JUNCTIONS, THE EQUIVALENT CHANNEL MODEL IS BEING USED TO ANALYZE THE LABORATORY TRANSPORT AND MICROSTRUCTURAL DATA. THE PHASE I EFFORT SHOULD ESTABLISH THE FEASIBILITY OF APPLYING LSCM TO THE THREE-DIMENSIONAL STUDY OF PORE GEOMETRY AND DEMONSTRATE THE MERIT OF THE COMPLEMENTARY LABORATORY PROGRAM AND ANALYSIS.