Taking well-X

a typical core well of the Wufeng-Longmaxi Formation in Southern Sichuan Basin

as an example

based on core observation

geochemical analysis

X-ray diffraction

physical properties testing

argon ion polishing SEM

hydrocarbon generation simulation and other testing methods

and by using the research idea of “source-storage coupling”

the properties of the core segment as the “source” and the “storage” respectively are analyzed

and the mechanism of “source-storage coupling” is further discussed

. The research results show that the bottom shale in Wufeng-Longmaxi Formation is characterized by sapmpelic kerogen

abundant organic matter

and high degree of thermal evolution

in which dry gas mainly generate. The average porosity of matrix is 6.5 %

mainly are inorganic pores. The inorganic pore types are mainly intergranular pore

clay mineral pore

feldspar alteration pore and pyrite intergranular pore. The average amount of adsorbed gas under formation temperature and pressure conditions is 0.9 m

3

/t. The average permeability is 0.38×10

-3

μm

2

which means it belongs to an ultra-low permeability reservoir. Generally speaking

the well-X has sufficient “source” at the bottom of the Wufeng-Longmaxi Formation with large amount of generated gas. The current stagnant gas volume is only about 54.8 % of the amount of generated gas

and the matrix pores are mainly inorganic pores. Meanwhile

organic pores are an important supplement. Free gas is the main body. The development of organic-rich shale section improves the permeability of the reservoir. At the same time

the biogenic siliceous minerals enhance the brittleness of the reservoir and make the reservoir easy to be fractured. Therefore

the organic-rich shale section is the best source-storage coupling interval

and also is the main interval of shale gas exploration and development and the key target layer of a horizontal well.