Deep‐water Fan Systems and Petroleum Resources on the Northern Slope of the South China Sea

Abstract

The shallow shelf deltalstrand arenaceous-pelitic deposit region in the north of the Pearl River mouth basin, sitting on the northern continental shelf of the South China Sea, has already become an important oil production base in China. Recent researched has revealed that a great deal of deepwater fans of great petroleum potentiality exist on the Baiyun deep-water slope below the big paleo Pearl River and its large delta. Based on a mass of exploration wells and 2-D seismic data of the shallow shelf region, a interpretation of sequence stratigraphy confiied the existence of deep-water fans. The cyclic falling of sea level, abundant detrital matter from the paleo Pearl River and the persistent geothermal subsidence in the Baiyun sag are the three prerequisites for the formation and development of deepwater fans. There are many in common between the deepwater shelf depositional system of the northern South China Sea and the exploration hotspots region on the two banks of the Atlantic. For example, both arc located on passive continent margins, and persistent secular thermal subsidence and large paleo rivers have supplied abundant material sources and organic matter. More recently, the discovery of the big gas pool on the northern slope of the Baiyun sag confirms that the Lower Tertiary lacustrine facies in the Baiyun sag has a great potentiality of source rocks. The fans overlying the Lower Tertiary source rocks should become the main exploration areas for oil and gas resources.

Dynamics Analysis of the Baiyun Sag in the Pearl River Mouth Basin, North of the South China Sea

“…I), the Baiyun sag trends nearly E-W, with The Baiyun sag has kept subsiding since the rifting stage. The deepwater turbidite fans of different ages in the sag were laid almost in the same position (Pang et al, 2004). This is supposed to be closely related with the evolution of the sag.…”

“…The Pearl River Mouth Basin lies on the northern continental margin of the South China Sea. Before drifting, the basin experienced three stages of rifting during the Tertiary (Li et al, 1989;Chen et al, 2003;Pang et al, 2004). The first stage named the Shenhu Event started at around the late Cretaceous on the northern margin of the South China Sea, and sediments controlled by NNE-NE trending faults of this period in the Zhu-1 depression were dated to be of the late Paleocene (about 54 Ma) (Chen et al, 2003).…”

“…an area of around 2x104 km2. Between the Main sag and the Sun et al Geological frame and structures of the Baiyun sag(Li et al, 1989;Chen et al, 2003;Pang et al, 2004).The ages of the magmas are:…”

Geochemical Indications of Possible Gas Hydrates in the Northeastern South China Sea

“…The brightness temperature anomalies of satellite based thermal infrared remote sensing, the high methane concentrations and the high thermoluminescence values of subsurface sediments are also possible related to conventional oil and gas migrations. Although there is no direct evidence for the seepage of oil and gas in the study area, there indeed exist the active natural gas migrations from the big gas pool on the northern slope of the Baiyun sag (Pang et al, 2004), which is adjacent to the study area. If based on the deep-basin gas accumulation theory (Wang et al, 2003), it is also possible for the deep-basin gas pool to migrate upwards, causing seepages of hydrocarbon gases in the study area.…”

Heavy Metal Distributions and Source Tracing in the Lacustrine Sediments of Dongdao Island, South China Sea

“…I). The nearby sea with thousands of reefs, atolls, submerged reefs and banks is probably one of the most biologically diverse bodies of water on the planet (Morton and Blackmore, 2001), and abundant oil and gas resources have been found in the South China Sea (Pang et al, 2004;Lu et al, 2006). Little researches have been conducted to date due to the distance from mainland China and the restriction on the travel to this coral island.…”