In order to study the lithology

property and brittleness of Gulong shale reservoir

a whole-section coring well

Well-GY8HC

is deployed in Gulong Sag. Detailed core description and element analysis show that the sedimentary microfacies in Gulong Sag are mainly semi-deep to deep lacustrine facies during the sedimentary period of Q1 to Q9 reservoirs

with thick organic-rich shale developed and can be subdivided into four types of lithology which are shale

siltstone

shell limestone and dolomite. Based on the classification principle of “structure+lithology” and combined with the lithology content characteristics

the lithofacies are divided into four types which are laminated shale

intercalated shale

massive dolomite and massive siltstone. The paleo-sedimentary environment is fresh water-brackish water+weak provenance+strong reduction in warm and humid climate

providing favorable place for organic matter formation and preservation. Comprehensive evaluation of three indexes of reservoir capacity

oil-bearing property and fracability shows that several reservoir space types of Q1 to Q3 reservoirs with good physical property

excellent oil bearing property and efficient fracability for shale oil production

being the most favorable interval for medium and high mature shale oil exploration in Daqing Oilfield.