The lower Cambrian Qiongzhusi Formation in southern Sichuan is one of the important strata for marine shale gas exploration. In the early stage

the exploration of black shale in Qiongzhusi Formation has achieved certain results

but the thin thickness of black shale restricts the breakthrough of commercial productivity. Silt-shale of Qiongzhusi Formation's gas logging shows high. Therefore

it is necessary to strengthen the systematic research of this new type of shale reservoir and widen the exploration field of unconventional shale gas. Based on the experimental data such as

TOC

X-ray diffraction

thin section

SEM

Helium porosity

pulse permeability

Nitrogen adsorption

and mer

cury intrusion porosimetry

the studies of the geochemical characteristics

petrological characteristics

reservoir space types

physical properties and pore structure of this new type of reservoir have been carried out. The study shows that the new type of shale reservoir is mainly composed of silty shale

which has the property of low

TOC

high brittleness

high porosity

good pore connectivity and high gas bearing. The main types of reservoir space are brittle mineral intergranular pores

carbonate minerals and feldspar dissolution intrapores

with only a small amount of organic pores. The support of silty brittle minerals is the key factor for pore preservation. It is generally considered that the new strata of shale reservoirs in Qiongzhusi Formation of southern Sichuan have good reservoir conditions for shale gas exploration.