Evaluation of shale gas resources in Yuqia sag of Qaidam Basin

Middle Jurassic Dameigou Formation shale, which is well developed in northern Qaidam Basin. Yuqia sag possesses favor-able geological conditions for shale gas, as shown by Chaiye-1 well; nevertheless, the resource potential of shale gas remains unclear. In combination with drilling and seismic data, the authors identified the parameters of gas-bearing shale such as thickness, area, and gas content of shale, and then evaluated geological resources of shale gas in Yuqia sag with the volume method. The results show that the resources of shale gas in the buried depth of 1500~3000m of Yuqia sag are very abundant and are likely to account for 38.95% of the total shale gas geological resources, and in particular, the free gas can account for 38% of the total gas, thus showing good resource prospect of shale gas in Yuqia sag.