Abstract: Mayang Basin in Hunan Province is the first block of PetroChina Liaohe Oilfield Company that can be registered by foreign companies. TheSulige gasfield is the largest onshore gasfield discovered in China so far, in which the main gas-bearing target strata feature in thin effective reservoirs (gas reservoirs), rapid longitudinal variation, and high risk of drilling. The thought on seismic prediction of effective reservoirs and its feasibility are demonstrated in the thesis based on analyzing the geological and geophysical characteristics of them. A full digital field data acquisition approach is proposed. It is emphasized that the dynamic characteristics of prestack gathers should be maintained during data processing. High-quality CDP gathers are obtained, which can be used for prestack inversion. Then restack inversion and AVO analysis are applied to predict effective gas reservoirs. In 2006, 30 wells were developed in the range of 100km2 of the gas field, based on applying systematic full-digital seismic techniques. Evaluation results show that the drilling success rate rises to 90% from 60%, gas zones drilled reaching 100%. This greatly improves the economic benefit of gasfield development.

Key words: effective reservoir, digital seismic, prestack inversion, Sulige gasfield