Study on the Heterogeneity of Conglomerate Reservoirs and Its Characterization Methods

Conglomerate reservoirs are highly heterogeneous due to the influence of sedimentary process. To characterize and quantify heterogeneity, a study was carried out on the cores of Mahu 1 well area in Mahu Sag. Through digital image analysis and micro indentation test, the gravel content, particle size distribution and micro-mechanical properties of conglomerate are analyzed, and the homogeneity value m calculated by Weibull distribution is used as the quantitative index of heterogeneity. Gravel size distribution is relatively discrete, with poor sorting, and the average particle size homogeneity degree value is 1.54. The mean homogeneity degree value of the elastic modulus in microdomain is 1.70. The gravel content is positively correlated with the overall heterogeneity of conglomerate. Based on the gravel particle size and its distribution, micro indentation modulus and its distribution, a characterization method suitable for evaluating the heterogeneity of conglomerate is proposed. The larger the heterogeneity index is, the smaller the uniaxial compressive strength of conglomerate is, showing a negative correlation. In this study, a conglomerate heterogeneity characterization method combining gravel size distribution and microdomain mechanical property distribution is established. The heterogeneous characterization method is the foundation for the study of mechanical properties of conglomerate.