Hwang Ingul¹, Keunpil Park¹
(1) Korea Institute of Geology, Mining, and Material, Taejun, South Korea

Abstract: Geohistory and petroleum potential of the Kunsan Basin, Yellow Sea

The Kunsan Basin was initially formed by left-lateral strike-slip fault probably related to the northeastward movement of the Phillippin plate during the Cretaceous. However, the basement is characterized by a series of half-grabens and tilted blocks bounded by listric faults. The rifting continued until Paleocene. At the end of Miocene, regional uplift resulted in erosion of thick Paleocene, Eocene, Oligocene and Miocene sedimentary sections.

Cutting samples and well log data from the five drilled wells suggest that the basin was filled with Cretaceous and Tertiary clastic sediments mainly deposited in alluvial fan, fluvial to shallow lacustrine environments. These wells suggest low petroleum potential with total organic carbon content less than 0.5%. However, climatic change during the middle Eocene from arid subtropical to humid subtropical resulted in deposition of thick deep lacustrine sediments in the central part of the basin. Lake level change during the late Eocene to Miocene probably resulted in deposition of thick fluvial, deltaic to sublacustrine fan sandstone. The deep lacustrine mudstone may act as a potential source rock, whereas overlying sandstone units are potential reservoirs.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana