Evaluation of hydrocarbon preservation on the Laoshan uplift

The Laoshan uplift is located in the middle of the South Yellow Sea basin, on which thick Mesozoic-Paleozoic marine sequences are widely distributed. Tectonically, it has suffered many times of tectonic movements, such as the Caledonian, Hercynian, Indosinian, Yanshanian and Himalayan. Early hydrocarbon accumulation might have been damaged to certain degrees by the tectonic movements. Therefore, the hydrocarbon preservation conditions are the key factors for the breakthrough of hydrocarbon exploration on the uplift. In this study, the relationship of hydrocarbon preservation with tectonic movements as well as that with cap-rock property is discussed. The differences in hydrocarbon preservation conditions on the Laoshan uplift are analyzed for hydrocarbon exploration in that area. The results show that the Gaoshi Stable Zone in the middle and southern part of the Laoshan uplift is a weak deformation zone. The lower Paleozoic of the zone is mainly composed of large traps, magmatic activity is relatively weak, and hydrocarbon preservation conditions are superior. However, in the Qingfeng deformation zone in the northern part of the uplift, the fractures and folds are strong, and the individual traps are small in scale and thus the hydrocarbon preservation conditions are relatively poor. In conclusion, the middle and southern parts of the Gaoshi stabilization zone are the key target areas for further oil and gas exploration.