In order to further study the pore characteristics of shale reservoir oin Sha-3 and Sha-4(the 3

rd

and 4

th

Member of Shahejie Formation respectively)and their accumulation significance in Liaohe depression

samples from 5 wells were chosen to conduct a series of experiments including focused ion beam-scanning electron microscope(FIB-SEM)

helium adsorption and desorption

whole rock analysis by XRD

microscopic examination of kerogen and related organic geochemistry experiments.The results show that there are 6 types of pore including intergranular pore

intragranular pore

inter-crystal pore

dissolution pore

organic pore and micro-cracks.Furthermore

development of these pores are not only related to sedimentary compaction

cementation and dissolution

but also closely related to the lithology

mineral fabric

type of organic matter and organic geochemistry.The intergranular pores and interlayer micropores and cracks of clay mineral aggregates make the greatest contribution to the storage and migration of shale oil and gas

and they are also the major controlling factor of the anisotropic(permeability)of the shale reservoir

followed by the dissolution pores and inter-crystal pores.The organic pores contribute the least due to the relatively poor development

but they still plays an important role in storage of absorbed shale oil and gas.Meanwhile

micro-cracks are also negligible in connecting macro-pores and meso-pores.In addition

large amount of organic pores are found in adhesive-combining organic matter with low maturity

indicating that clay minerals play an important role in the early period of hydrocarbon generation.The feature of close symbiosis between organic matter and minerals(mainly clay minerals)also reflects the close relationship between the preservation pattern of organic matter and hydrocarbon generation.The experiments also demonstrate that the amorphous solid is the major contributor to the generation of shale oil and gas in Sha-3 and Sha-4 shale.