In order to look for new fairways for future gas exploration in the Sichuan Basin

we worked on revealling the sedimentary characteristics and distribution of favorable reservoir facies in the Middle Triassic Leikoupo Formation.The study took marine carbonate sequence stratigraphy and reservoir sedimentology theory as guidance.Based on the markers in logging data

from cores

and sequence boundaries including unconformity

we conducted the sequence stratigraphy division and identification of sedimentary facies.Then spatial boundaries of sedimentary facies in each sequence are delineated

and the lithofacies paleogeographic map of each system tract in every sequence are compiled to predict favorable reservoir facies distribution.The results show that the Middle Triassic Leikoupo Formation in the Sichuan Basin develops a set of shallow water carbonate platform sedimentary system

including 4 major sedimentary facies

namely

restricted platform

evaporitic platform

platform edge and open platform.In general

the formation appears to be higher in the east and plunges to the west

with significant uplift and sag within the platform driven by early Indosinian tectonic movement.Due to basement uplift

some of the upper sections of the formation are eroded by long-term exposure

companied by development of a weathering crust.Furthermore

based on sedimentary facies recognition and sequence interface markers

we divided the Middle Triassic Leikoupo Formation into 4 third-tier sequences and 8 system tracts:the paleo-uplift in the central basin and its surrounding dolomite flat

and the platform edge bank of the northwestern Mianzhu and Jiange uplifts

are favorable reservoir facies because of their better reservoir properties and effective coupling of reservoir and caprock.Therefore

we conclude that these fairways are the most favorable areas for future exploration in the Middle Triassic Leikoupo Formation in the Sichuan Basin.