Characteristics of Oligocene sediments in Block 05-1(a), Nam Con Son basin
Abstract
The paper presents the development of Oligocene sediments together with biostratigraphic, etrographic and geochemical characteristics to facilitate petroleum system modelling in Block 05-1(a). The biostratigraphic study results show the existence of Oligocene sediments, which are distributed from the southern flank to the northern uplifts of Dai Hung field and were deposited in the environmental conditions from coastal plain to shallow marine. The lithological composition is mainly fine-grained to coarse sandstone and tends to coarse towards Dai Hung uplift. The visible pore is 2.0 - 6.5% and affected by the compression process from 10 - 80% and cemented by secondary minerals from 10 - 70%. The source rock in the southern flank is rich in organic matter, reaching thermal maturity to the oil-window and having potential for mixed oil-gas while Dai Hung uplift is prone to gas potential. This also shows that the characteristics of source rock in Block 05-1(a) are local and do not represent the source rocks of the region.
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