Analysis of Formation Conditions of Shale Oils in the Changling Depression, Sourthern Songliao Basin

Previous research has reported that organic-rich shale is hydrocarbon source rock or good hydrocarbon sealing barrier, while it is not oil and gas reservoir. Therefore, it has not gained attention in the oil and gas exploration and development. However, with the discovery of rich oils in shale, shale has been proven to be a good resource of shale oils. So far, oil industries in the world are turning their attention from the conventional oil and gas to the unconventional oil and gas, such as tight oil (gas) and shale oil (gas). Shale oil and gas has become the hotspot of oil and gas exploration and development, which is expected to be important oil and gas fields in the next 20 to 30 years. Songliao Basin, which is one of the largest continental petroliferous basins in China, is rich in oil and gas resources. Changling Depression is located in the south of the central depression of the Songliao Basin. It covers an area of more than 20, 000 km, with a basal maximum depth of about 9000 m. There were several tectonic episodes during the depression period in the Changling Depression. In the late period of the Nenjiang Formation, tectonic movement is the strongest, which affected by fold uplift in southeast uplift area. While the strong pressure torsion movement in the late period of the MingShui Formation contributes to the formation of central depression area and west slope area. After depression period, the study area was influenced slightly by the tectonic movement in the late period of the Nenjiang Formation. Structures are simple and stable, and they belong to large depression. Moreover, faults, which develop not very well, can be divided into the Daqingzi low uplift, Qianan sub-concave, Heidimiao sub-concave, west slope, southern slope and eastern slope, ect. 2 Forming Conditions of Shale Oil