A set of shale-dominated source rocks series were deposited during the heyday of lake basin development in the Member 7 of Triassic Yanchang Formation, Ordos Basin, and the thickness is about 110 m. Aimed at whether this layer can form large-scale oil enrichment of industrial value, comprehensive geological research and exploration practice have been carried out for years and obtained the following important geologic findings. Firstly, widely distributed black shale and dark mudstone with an average organic matter abundance of 13.81% and 3.74%, respectively, lay solid material foundation for the formation of shale oil. Secondly, sandy rocks sandwiched in thick organic-rich shale formations constitute an oil-rich “sweet spot”, the average thickness of thin sandstone is 3.5 m. Thirdly, fine-grained sandstone and siltstone reservoirs have mainly small pores of 2–8 μm and throats of 20–150 nm in radius, but with a large number of micro-pores and nano-throats, through fracturing, the reservoirs can provide good conductivity for the fluid in it. Fourthly, continued high-intensity hydrocarbon generation led to a pressure difference between the source rock and thin-layer reservoir of up to 8–16 MPa during geological history, driven by the high pressure, the oil charged into the reservoirs in large area, with oil saturation reaching more than 70%. Under the guidance of the above theory, in 2019, the Qingcheng Oilfield with geologic oil reserves of billion ton order was proved in the class I multi-stage superimposed sandstone shale reservoir of Chang 7 Member by the Changqing Oilfield Branch through implementation of overall exploration and horizontal well volume fracturing. Two risk exploration horizontal wells were deployed for the class II thick layer mud shale interbedded with thin layers of silt- and fine-sandstones reservoir in the Chang 7₃ submember, and they were tested high yield oil flows of more than 100 tons per day, marking major breakthroughs in petroleum exploration in class I shale reservoirs. The new discoveries have expanded the domain of unconventional petroleum exploration.

在鄂尔多斯盆地三叠系延长组七段湖盆发育的全盛时期，沉积了一组以页岩为主的烃源岩系列，厚度约110 m。针对这一层能否形成大规模的工业增值油品，多年来进行了综合的地质研究和勘探实践，获得了以下重要的地质发现。首先，分布广泛的黑色页岩和深色泥岩，平均有机质丰度分别为13.81％和3.74％，为页岩油的形成奠定了坚实的物质基础。其次，夹在富含有机物的厚页岩地层中的砂岩构成了富含石油的“甜点”，薄砂岩的平均厚度为3.5 m。第三，细粒砂岩和粉砂岩储层主要有2-8μm的小孔和半径为20-150 nm的喉道，但由于裂隙，大量的微孔和纳米喉道可以提供良好的电导率。里面的液体。第四，持续的高强度碳氢化合物的产生在地质史上导致源岩与薄层油藏之间的压力差高达8–16 MPa，这是由于高压所致，大面积地向油藏中注入了石油。油饱和度达到70％以上。在以上理论的指导下，2019年，长庆油田分公司通过实施整体勘探和水平井体积压裂技术，在长七段Ⅰ类多级叠加砂岩页岩储层中证实了具有十亿吨级地质油藏的青城油田。长7井的II类厚层泥页岩夹有薄层粉砂岩和细砂岩储层，部署了两个风险勘探水平井₃个子成员，他们接受了每天100吨以上的高产油流测试，标志着I类页岩油藏的石油勘探取得了重大突破。新发现扩大了非常规石油勘探的领域。