Silurian Exploration Potential and Direction in Sichuan Basin
Tonglou Guo and Hanrong Zhang
SINOPEC Southern Company, Chengdu, China
There are four main source rocks in Sichuan basin which are Lower Cambrian, Upper Ordovician-Lower Silurian, Permian and Triassic. Trillion cubic meter reserves have been found in Puguang and Yuanba oversized gasfield in Changxing formation of Permian and Feixianguan formation of Triassic. According the research, the gas comes from the underlying Permian strata. The 2nd and 4nd member of Triassic Xujiahe formation tight gas reservoir had been discovered, which source rock are the 1nd, 3nd and 5nd member of Triassic Xujiahe formation.
The Upper Ordovician-Lower Silurian strata distribute at a large area and have a large thickness. Jiaoye 1 well systematic coring analysis reveals that the abundance of organic matter and moderate maturity. However, we only discovered Dachigan gas reservoir taking this strata as source rock and its reservoir scale are far inferior to Permian.
And where are the generated hydrocarbons of the Upper Ordovician-Lower Silurian? Whether it formed tight gas in the overlying Xiaoheba formation or shale gas in the Silurian strata? Jianshen 1 well has discovered 50 thousand cubic meters in the Silurian Xiaheba formation. What if we change the exploration thinking, we may discover another important exploration area.
This paper focuses on the anatomy of the new drilled well-Jiaoye 1. Through Upper Ordovician-Lower Silurian systemic coring data analysis combined with the research of regional Silurian source rocks and comparison between Permian and Silurian source rocks relevant parameters, the Silurian strata exploration potential and direction were discussed.
AAPG Search and Discovery Article #90175©2013 AAPG Hedberg Conference, Beijing, China, April 21-24, 2013