Formation and tectonic evolution of Laoshan uplift of South Yellow Sea basin and its effect on hydrocarbon accumulation

Based on the newly acquired drilling data and seismic data, comprehensive study has been devoted to the stratigraphic and tectonic evolution of the Mesozoic-Paleozoic on the Laoshan uplift in the South Yellow Sea Basin, and comparison is made with southern Jiangsu Province and western Zhejiang Province in the land area of the Lower Yangtze platform. It is revealed that there are two depositional stages, the first stage from late Sinian to early Ordovician, and the second stage of early Triassic, dominated by carbonate platform deposits consisting of limestone and dolomite, while deep water deposits of mudstone and argillaceous limestone occur in the western Zhejiang Province. During the period from Late Ordovician to Silurian, tectonic movement became intensified. The Laoshan uplift rose as a whole in Mesozoic and Cenozoic. At the same time, thicker dolomite reservoirs were formed, which provided large space for hydrocarbon accumulation. The uplift formed in the early stage favored the migration of hydrocarbons upwards from the deep water basin or aulacogen and finally accumulated in the traps of the uplifted area.