Dengying Formation is the oldest gas bearing strata which have ever been found in Sichuan Basin.Since Sichuan Basin experienced polycyclic tectonic movements,the reason why there still are major gas reservoirs is attributed to late hydrocarbon accumulation.According to the analyses of gas components,isotopes and fluid inclusions,combined with regional geological data,three salient features of late gas accumulation in Dengying Formation of Sichuan Basin are concluded:(1) Extensive hydrocarbon sources (oilcracked gas and exsolved gas from water phase) provide material basis for late gas accumulation; (2) General development of gas inclusions reflects a wide range of natural gas filling in Himalaya period; (3) Readjustment of oil and gas in Himalaya period resulted in the formation of new gas reservoirs.Based on tectonic deformation features in Himalayan period,gas reservoirs of Dengying Formation can be divided into three types.The most favorable type is the native gas reservoir,followed by the adjustable one.The influence of Himalayan movement should be paid great attention to during the exploration of natural gas in Sinian or other ancient strata of Sichuan Basin.The relatively stable paleo uplift and ancient slope belt which have good preservation conditions are favorable exploration areas.
Sichuan BasinDengying FormationLate hydrocarbon accumulationPaleo-upliftNatural gas
NETL
NSTL
万方数据
维普
