Shale petrophysical evaluation of the Middle Jurassic Dameigou Formation in Chaiye1 Well, Qaidam Basin

Petrophysical evaluation of shale reservoirs is the basis of the fracturing project. The drilling project of Chaiye1 well was organized by China Geological Survey in 2013. The results of conventional logging and element capture spectroscopy of Chaiye1 well provided data for shale gas exploration and development of Qaidam Basin. Based on the open hole logging data, core analysis data, lithology, physical properties, geochemical characteristics, gas-bearing properties and geomechanics, this paper has summarized reservoir evaluation and fracturing characteristics. The organic-rich shale with high gamma, high acoustic, high neutron, high resistivity, low density features at least has the thickness of 128.1m, the total organic carbon content is between 3.20% and 4.20%, the total gas content is between 1.50~4.50m³/t, and the brittle mineral content is between 45% and 76%, as shown by the result of petrophysical evaluation. In addition, three potential layers are recognized in Chaiye1 well, with the shale inⅠandⅡintervals characterized by high Young's modulus and low Poisson's ratio being most favorable for perforation optimization design.