Distribution law and reservoir forming characteristics of shale oil in America

In recent years, America has achieved great success in the exploration and development of shale oil.Through the analysis of the distribution law and the reservoir characteristics of shale oil in America, it is held that, shale oil mainly distributes in West Coast region, Rocky Mountain region, Gulf Coast region, southwest region, and mid-continent region, basin types include foreland basin, craton basin and graben basin, and Mississippian of Neopaleozoic and Cretaceous of Mesozoic are the main shale oil-bearing strata. The reservoir characteristics of shale oil in America are more lithologic association types, high TOC (>2.0%), favorable kerogen type (mainly type IIoil-prone kerogen), moderate Ro(0.6%~1.0% in Bakken and Barnett, 1.0%~1.3% in Eagle Ford), tight reservoir (shale porosity 2%~3%, interlayer or interbed porosity<10%), high content of brittle mineral (quartz volume fraction>40%) or carbonate (>60% in Eagle Ford), high formation pressure (pressure coefficient 0.99~1.80), and light oil(density<0.8448 g/m3).According to the reservoir characteristics, the shale oil in America can be divided into two types: pure shale system shale oil and hybrid system shale oil. Lacustrine shale formations of Mesozoic and Cenozoic in China have the basic conditions of forming shale oil, and the prospect regions and strata for shale oil exploration are proposed.