A Case Study for Detecting Thin Tight Sand Gas in the Sulige Gas Field from Joint PP/PS Geostatistical AVO Inversion

The Sulige gas field is is China’s largest onshore gas field characterized by low porosity, low permeability and low abundance. Reservoirs are dominated by coarse-grained sandstones of the Lower Permian Shihezi and Shanxi formations, especially those of the He 8 and Shan 1 units. Geostatistical inversion method integrates the well log data, geological constraints, geostatistical parameters and seismic data to produce a highly detailed reservoir description. A 3D-3C seismic data was acquired over the Sulige gas field in 2003. Application of joint PP/PS pre-stack geostastistical inversion methodology in the He 8 unit in Sulige gas field demonstrates that important improvement can be made in reservoir characterization when the reservoir is below the seismic resolution. These results will enhance interpretations for optimal well placement and field development.