Continental shale oil resources and favorable area evaluation of Biyang depression

Biyang depression is a typical Cenozoic oil enriched depression in the east of China and Paleogene Hetaoyuan formation deposited lacustrine shale containing rich organic matter.Previous studies show Hetaoyuan formation in the deep depressed zone of Biyang depression is of favorable conditions for terrestrial shale oil.For the past two years,comprehensive research and geological evaluation of terrestrial oil in Biyang depression have been carried out.There are a series of geological evaluation technologies on 8 key items,such as multi-parameter geological evaluation,petrological analysis,logging reservoir evaluation,reservoir evaluation logging,geophysical reservoir prediction,resource evaluation,favorable target evaluation,and optimized design on horizontal wells.Among them,the resource evaluation and favorable area evaluation technology for the shale oil and gas geological evaluation are the most critical technologies.Through key parameters research on shale hydrocarbon thickness,are and hydrocarbon-bearing resources,by use of volumetric method,the shale oil resource of main shale layers is up to 4.2253×108t,shale gas resource is up to 729×108 m3.Six evaluation indicators,such as organic carbon,thermal evolution,porosity,permeability and etc have been utilized to initially establish the evaluation criteria for continental shale oil favorable area in Biyang depression.Through optimization of horizontal wells deployment,high oil flow has been achieved after fracturing,which was a major breakthrough for continental shale oil exploration in China.