Ultimate Potential Nature Gas Resource Prediction and Exploration Direction in Sichuan Basin

The ultimate natural gas resources of Sichuan Basin were predicted by the application of hydrocarbon reservoir scale sequence method. The results revealed that a total of 236 gas reservoirs exist in Sichuan Basin, with total expected natural gas resources of 57718×108m3.110 gas reservoirs are undiscovered, with geological reserves of 4.04×1012m3, accounting for70.0% of the total natural gas resources, among which, 17 undiscovered gas reservoirs have resources of more than 1000×108m3, 13 undiscovered natural gas reservoirs have resources of 500-1000×108m3 and 15 undiscovered gas reservoirs have resources of 100-500×108m3. The undiscovered natural gas resources mainly lie in the following key exploration fields: Permian-Triassic reef flat reservoir of Huankaijiang-Liangping continental shelf and deep to ultra-deep layers of continental Xujiahe Formation in West Sichuan, medium to shallow layers of Northeast Sichuan and Central Sichuan focused on Xujiahe Formation, piedmont zone of Longmen Mountain and Micang-Daba Mountain, oolitic flat of Jialingjiang Formation of East Sichuan, South Sichuan and North Sichuan as well as five large sets of unconformity surfaces, namely top surface of Sinian Dengying Formation, top surface of Middle-Upper Ordovician, top surface of Middle Carboniferous, top surface of Permian Yangxin Series and top surface of Leikoupo Formation.