Using geochemical

sedimentary and hydrocarbon accumulation analysis methods

this paper studied the characteristics of source rocks

hydrocarbon migration and accumulation of the low resistivity reservoirs of the 1

st

Member of Zhujiang Formation(Zhu1)in the low-amplitude structure of Qionghai salient in Wenchang-13 block

Qionghai salient.The following results were obtained.The oil of the Zhu1 low resistivity reservoir in Wenchang 13-X is mainly sourced from the shallow lacustrine mudstone of Enping Formation in Wenchang sag

which is another high quality source rock in addition to the Wenchang Formation mudstone of mid-deep lacustrine faciesin.The low resistivity reservoirs of Zhu1 in Wenchang13 block are of structural-lithologic composite type developed in the low amplitude drape anticlines.The main reservoir consists of offshore fine muddy siltstone with fine grain and high mud content

which are the main causes of the low resistivity.The low resistivity reservoirs area characterized by low amplitude structure and low permeability.The low resistivity reservoirs are secondary accumulation with hydrocarbons sourced from the underlying high resistivity reservoir.The low resistivity and high resistivity reservoirs superimpose vertically to form a hydrocarbon enrichment zone.The low resistivity reservoirs in low amplitude structure are important targets for potential-tapping in mature area.