Prediction of a low tight sandstone reservoir in the Majing gas field, Sichuan Basin, China

The Penglaizheng gas reservoir is a tight sandstone reservoir with strong heterogeneity in the Majing gas field in the Sichuan Basin, China. To identify the reservoir, we attempt to use two measurements: synthesized interval transit time ratio (DT) and apparent fluid recognition index (PF). Gas reservoirs can be recognized effectively by extracting their features from log and seismic data in different sizes. The gas-bearing seismic response of the Penglaizheng reservoir, i.e., ‘strong wave amplitude and low wave impedance’, obtained from seismic attributes such as amplitude, relative and resolute impedance, and seismic coherence, is observed in an identified profitable area of the Majing gas field. The techniques of seismic attribute analysis and log identification of gas-bearing horizons, acquired from near-tight to tight reservoirs in the Penglaizheng reservoir in the Majing field, can also be used for formations with similar characteristics.