Understanding of the physics of fluid flow throughsedimentary rock is fundamental to the petroleum industry. Although the transport properties (permeability and connectivity)are directly related to the porosity, complexity arises becausethey depend critically on the geometry of the pore space. Thequantitative description of the pore structure is thus critical toevaluate and motivate theoretical models for the transportproperties of porous rocks. Because the coordination (i.e.,connectivity) of the pore space is critical to the macroscopictransport properties, only limited information may be obtainedusing conventional two-dimensional imaging techniques. In thisproject, a new technology, laser scanning confocal microscopy(LSCM), is being applied to the study of the pore geometry ofsedimentary rocks. Three-dimensional imaging is possible becauseLSCM can "slice" thin optical sections of thick specimens withremarkably high resolution. In the Phase I research, the threedimensional pore geometry of representative reservoir rocks isbeing characterized in terms of coordination number, poredistribution (e.g., nodal pores, cracks, and tubes), pore size,crack length and width, anisotropy, etc. Laboratory measurementsof the pressure dependence of permeability and resistivity willcomplement the quantitative microstructural analysis. Becausefluid flow in sedimentary rocks is controlled by sheet-like"throats" (i.e., cracks) at two-grain junctions, the equivalentchannel model is being used to analyze the laboratory transport andmicrostructural data. The Phase I effort should establish thefeasibility of applying LSCM to the three-dimensional study of poregeometry and demonstrate the merit of the complementary laboratoryprogram and analysis.Anticipated Benefits/Potential Commercial Applications as described by the awardee:This research will contribute to the basicunderstanding of the internal microscopic architecture of reservoirrocks; specifically, it will study the effect of diageneticenvironment on, and relationship between, microstructure andtransport properties. A new technique for the three-dimensionalcharacterization of pore geometry will be developed. A databasewill be constructed detailing the three-dimensional pore topologyas well as laboratory measurements of the transport properties ofreservoir rocks as a function of pressure. Methods to predictformation permeability, given pore geometry and resistivity, willbe developed. Such information will help identify optimal recoverystrategies and estimate reservoir producibility.
