摘要
The Feixianguan Formation in the Yuanba gas field, northeastern Sichuan may be divided, on the basis of cores, thin sections, well logs and seismic data, into two third-order sequences: SQ1 representing the 1st and 2nd members, and SQ2 representing the 3rd and 4th members of the Feixianguan Formation. Grounded upon the carbonate platform, both SQ1 and SQ2 are made up of the transgressive and highstand systems tracts and lack of the lowstand systems tract. Till the deposition of SQ2, the whole area graded into the shallow-water carbonate platform dominated by the transgressive and highstand systems tracts representing the open platform deposits in the transgressive phase and evaporate platform deposits in the highstand phase.