Luochang Syncline is located in the southern Sichuan Basin.The main target layer of Wufeng-Longmaxi Formations shale has been deformed during Indosinian

Yanshanian and Himalayan.The shale deformation was relatively weak with moderate burial

promising good condition for shale gas accumulation and preservation.Thus the syncline has become an important part of the core shale gas area in the upper Yangtze region.According to characteristics of lithology

electrical

mineral composition

organic matter and gas bearing property

Wufeng-Longmaxi Formations shale of the Syncline can be divided into three third-order sequences

three lithologic sections

three types of facies and four types of sub-facies and various of micro-facies.Deep water shelf depositional stage is the best stage (layerⅠ) for possible organic rich shale deposition and could be subdivided into five layers

namely Ⅰ

1

Ⅰ

2

and Ⅰ

3

Ⅰ

4

Ⅰ

5

.Integrated analysis of physical property and pressure coefficient of the shale in the Huangjinba development block

shale gas is mainly preserved in the residual syncline which was the main part of deep shelf.The gas reservoirs are divided into two sets

the bottom of the Longmaxi Formation and the Wufeng Formation

separated by the Guanyinqiao Member limestone.Based on fracturing evaluation and production test results

the bottom of Longmaxi Formation Ⅰ

3

and Ⅰ

4

are the best production layers after fracture transformation.