The measurement of matrix and fracture properties in naturally fractured low-permeability cores using a pressure pulse method

Naturally fractured reservoirs are important sources of oil and gas throughout the world. The properties of the matrix and the fractures are key parameters in predicting the performances of naturally fractured reservoirs.;This dissertation describes a new laboratory technique to determine (1) the porosity of the matrix, (2) the permeability of the matrix, (3) the effective width of the fractures, and (4) the permeability of the fractures, in a naturally fractured, low permeability core using a pressure pulse method.;New laboratory equipment has been designed and constructed to conduct pressure pulse tests in either a homogeneous or a fractured core sample. Analytical solutions have been developed to model gas flow in a fractured core sample during a pressure pulse test. An automatic history matching program has been developed to analyze the laboratory measured pressure transient data using the analytical solutions. Two leak compensation methods have been developed to compensate for the gas that leaks from the system during a pressure pulse test.;The new technique has been used to measure the matrix and fracture properties in twelve naturally fractured, Devonian Shale cores. The results of measurements are presented in this dissertation. The porosity values measured using the new technique compare favorably with those measured by Core Laboratory using crushed samples from the same cores.;A two-dimensional, two-phase finite difference simulator has been developed to simulate pressure pulse tests on a computer. The finite difference simulator has been used to check the validity of the new analytical solutions and to investigate the two-phase flow during relative permeability measurements.;The technique we developed in this research is new to the petroleum industry. Our laboratory equipment is unique, and the analytical solutions have not been published in the literature. With this technique, we can measure matrix properties as low as 10...