Rock Physical Properties of Longmaxi Shale Gas Formation in South Sichuan Province, China

Deep shale gas (burial depth > 3500 m) in the Longmaxi Formation of southern Sichuan Province will be primary target for exploration and development China a relatively long period. However, lack physical basis “sweet-spots” seismic well-logging prediction is caused by uncertainty rock properties deep research area. Acoustic hardness measurements were performed on samples from layer Sichuan. Microtextural characteristics also analyzed conventional optical microscopy scanning electron microscopy. Based these measurements, control factors are discussed. It shown that have similar to shallow mineral composition, microtexture, pore type. organic undeveloped, while dissolved pores more developed. For high-quality (total content 2%), crystal quartz biological origin forms framework samples, resulting effective dynamic static properties, reflecting elastic behavior rigid aggregates. organic-lean < orientated detrital clay particles take role load-bearing grains. Therefore, samples’ overall mainly controlled “soft” clay. The grain variation organic-rich results an overturned “V”-type change terms velocity versus content. Organic-rich show apparent low Poisson’s ratio. has slight velocity–porosity trend, shows significant trend. In addition, due difference microtexture between shale, two kinds reservoir rocks can discriminated cross plots P-wave impedance ratio Young’s modulus Change reflects with biological-origin as grains higher brittleness. less impact brittleness grain. Our provide experimental geophysical identification layers.