Understanding of the interior of the Archaeozoic metamorphic basement rocks in Ciyutuo buried hill

Liaohe Depression

is relative poor.The comprehensive research that involves logging

seismic

core and experimental data could be of great help to detect the lithology and distribution of the basement rock

types and characters of reservoir space as well as the impact of lithology on the reservoir physical properties

to further explore and develop petroleum effectively

and to perfect the new theory of petroleum accumulation in the interior of basement rock reservoirs.The Archaeozoic basement rock litho- logy in the study area is quite complicated

and can be classified into 11 categories and 18 kinds.The lithologies of the me-tamorphic reservoir include migmatitic granite

biotite granite-gneiss

migmatitic-gneiss

cataclasite and murbruk rock.The basement rocks feature vertical segmentation and lateral zonation of lithology:migmatitic granite with cataclasite interlayer occurring the lower part

migmatitic-gneiss and migmatitic granite with cataclasite interlayer in the middle-lower part

and gneiss in the upper part.The reservoir space of the metamorphic buried hill is cracks and dissolved pores and fractures starting from the cracks

with the structural fractures being dominant.The fractures are developed to various degrees in different lithologies

have strong heterogeneity

and are characterized by zonation.Reservoir zones with highly developed fractures are the main target of the exploration.The basement rock reservoir in Ciyutuo buried hill is controlled by petrology and mineralogy.Fragmented migmatitic granite and fragmented granite-gneiss could be quality reservoirs.Statistics show that the cataclasite-migmatitic granite with a ferromagnesian content of less than 10% and the cataclasite granite-gneiss with a ferromagnesian content of less than 12% are favorable for the formation of quality reservoir rocks.