Exploration of the lacustrine shale gas in Sichuan Basin has discovered strong gas shows and/or commercial gas flow in the Middle and Lower Jurassic of Jiannan

Fuling

and Yuanba areas

east of Sichuan

which are prospective areas for petroleum exploration.Compared with organic-rich marine shale

the lacustrine shale is characterized by fast change of sedimentary facies

diversity of lithofacies(interbed and alternating beds)

low abundance of organic matters

strong reservoir heterogeneity and complex source-reservoir configuration.According to the types of lithofacies

the lacustrine shale can be divided into two types of source-reservoir configuration

namely the type of “reservoir interbedded within source rocks” configuration and the type of “source-reservoir alternating” configuration

which can be further subdivided into four subtypes.Through such methods as organic geochemistry

microscopic storage and permeability experiments and nano CT

we stu-died the characteristics of hydrocarbon generation

storage capacity and fracturability for each type of source-reservoir configurations

and established the evaluation model for source-reservoir coefficients conformable to the characteristics of the lacustrine source-reservoir configurations of various types

with each type as an independent “source-reservoir” unit.The evaluation results show that the source-reservoir configuration of the alternating shale and shell limestone deposited in a carbonate lake has favorable conditions for hydrocarbon generation

shale gas storage

permeability and fracturability

beneficial to the formation and stimulation of shale gas reservoirs

thus functions as the most favorable type of source-reservoir configuration of the lacustrine facies.In comparison

the source-reservoir configuration with shell limestone interbedded within shale has favorable hydrocarbon generation and reservoir conditions

but poor permeability and fracturability

thus is fair in quality.The above two types can be taken as the preferred layer for the development of lacustrine shale gas.