THE FORMATION AND DEVELOPMENT OF PALEO-UPLIFT IN CENTRAL SICHUAN AND ITS OIL/GAS PROSPECT

In this paber,the recent data from wells, regional seismic profile and regional geology have been integrated and it is concluded that the Paleo-uplift is developed through-out geological history. This nose form paleo-uplift is a structural erosion uplift with Ew trend formed during Caledo-nian movement and subsequent Devonian-Carboniferous uplifting. Thereafter, it turned to near NEE trend during Indosinian time and continued to the time of Yanshanian and Xishanian. There are plenty of gas source rocks in the uplift area and there are five sequences where the abundance of organic carbon is computed to be 2 Mt/Km², mainly attributed to Lower Paleozoic and Tengyin Formation(Zn),and some to Permian systems.Based on the resource prediction,the resources of Lower Paleozoic marine facies sequences are of 72 percent of the total resources in the area. The regional sealing condition is excellent for the Paleo-uplift and its top erosional fault plane during the peak stage of oil/gas generation in Indosinian time without any influence of Sichuan movement. The traps in the area can be divided into four types: the reservoir related to deposition, the traps related to the control of paleo-erosional plane, gas pool formed in early stage influenced by regional paleo-uplifting and paleo-structure, and various traps formed in late stage of folding and fanlting. Finally, the possible reservoir types and their oil/gas prospects are made for different locations of the paleo-uplift.