Abstract:

The predicted Sinian and Cambrian gas resource amounts to about 1.42×10¹² m³ in from western Hubei to eastern Chongqing areas，the prospect for the exploration is broad.Lower Cambrian mudstone is mostly hydrocarbon source rock and has good gas generating potential.Dengying Formation of Sinian and Shilongdong Formation of Lower Cambrian are two sets of high quality reservoirs attributed to favorable sedimentary facies，paleokarst action and fractures linkage.The sealing ability of the multi cap cocks is good，which is beneficial to the preservation condition of natural gas.According to hydrocarbon source rocks evolvement，tectonic evolvement and paleouplife evolvement，reservoiring course of Sinian and Cambrian natural gas in the areas is grouped into three phases：lithologic（paleokarst）stratum reservoirs during CaledonianHercynian，structural reservoirs during Indo Chinese epoch early Yanshanian，reservoirs adjustment and finality during ate Yanshanian Himalayan.Based on these facts and combined with the analysis of drilling date，it is indicated that there are excellent gas reservoir formation conditions in the areas and that Shizhu synclinorium is an important target in from western Hubei to eastern Chongqing areas for future Sinian and Cambrian natural gas exploration.Jiannan structure is a large scaled trap and has good trap style，so that it should be taken as the most favorable exploration target.

Key words: reservoiring condition, reservoirforming pattern, exploration direction, Sinian, Cambrian, western Hubei and eastern Chongqing areas