Study On Petrophysical Parameters Of Shale Gas Reservoir

Free and adsorbed coexisting of accumulated characteristics, continuous accumulation of the aggregation model, different from the conventional gas reservoir characteristics and evaluation content, that determined the particularity of shale gas reservoir. It is the key to realize the efficient evaluation of shale gas that studied the petrophysical characteristics of shale gas, and serach for scientific calculation model of reservoir parameter. It is of great significance to "dessert" prediction and optimization, efficient and large-scale development for shale reservoir.Based on the results of the domestic and foreign research, and taked the shale in the southeast of Sichuan Longmaxi as the research object. by combining theoretical analysis and experimental research, studied systematically on relationship between rock physical parameters of acoustic, electric, radioactive and mineral composition, organic carbon content, and explored the evaluation model of mineral composition and TOC which is based on natural gamma ray spectrum, sonic, resistivity. Results and understanding are as follows:(1) The main minerals of underground and outcrops shale are quartz and clay minerals, illite is the major of clay minerals, illite/smectite, chlorite as followed.(2) The correlation between sonic interval transit time of vertical bedding and quartz or clay is better than sonic interval transit time of parallel bedding; the correlation of sonic interval transit time to quartz is better than that of clay; With the increase of frequency, the correlation coefficient between sonic interval transit time and quartz or clay gradually becomes larger and the correlation becomes better.(3) Whether parallel bedding or vertical bedding, between rock resistivity and quartz or clay exist certain correlation; the resistivity of parallel bedding correlated with quartz or clay is better than the resistivity of vertical bedding; the correlation of resistivity to quartz is better than that of clay.(4) The correlation of quartz with uranium, uranium and potassium was significantly and negatively, with Th, K and Th/K was negatively correlated.The correlation of clay with uranium, thorium and potassium was remarkable and was positively, with uranium, potassium and potassium was positively correlated.(5) The correlation of TOC with Th, K, U/Th and U/K was relatively good, and negatively correlated with Th and K, positively correlated with U/Th and U/K.(6) Whether it is parallel to the bedding or vertical to the bedding, good correlation between TOC and resistivity, and was negatively correlated. The correlation of TOC and density was positive.(7) synthesized the index of sonic interval transit time, resistivity, natural gamma ray, established the calculation model of quartz, clay and TOC through multiple linear regression.