scholarly journals Focused Fluid Flow, Shallow Gas Hydrate, and Cold Seep in the Qiongdongnan Basin, Northwestern South China Sea

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Minghui Geng ◽  
Ruwei Zhang ◽  
Shengxiong Yang ◽  
Jun Guo ◽  
Zongheng Chen
Keyword(s):  
Fluid Flow ◽  
South China Sea ◽  
South China ◽  
Gas Hydrate ◽  
Qiongdongnan Basin ◽  
Cold Seep ◽  
Shallow Gas ◽  
Free Gas ◽  
China Sea ◽  
Gas Chimneys

The 3D seismic data acquired in the central Qiongdongnan Basin, northwestern South China Sea, reveal the presence of shallow gas hydrate, free gas, and focused fluid flow in the study area, which are indicated by multiple seismic anomalies, including bottom simulating reflectors, polarity reverses, pulldowns, minor faults, and gas chimneys intensively emplaced within the shallow strata. A new cold seep is also discovered at approximately 1520 m water depths with an ~40 m wide crater in the west part of the study area. Water column imaging, seafloor observation, and sampling using the remotely operated vehicle “Haima” demonstrate ongoing gas seepages and shallow gas hydrates at this site. Thermogenic gas in the study area migrates from the deep reservoir through the gas hydrate stability zone along deep faults and gas chimneys, forms shallow gas hydrate and free gas, and sustains localized gas seepage within this cold seep. The results provide insight into the relationship between shallow gas hydrate accumulation and deep hydrocarbon generation and migration and simultaneously have important implications for hydrocarbon explorations in the Qiongdongnan Basin, northwestern South China Sea.

Subsurface fluid flow at an active cold seep area in the Qiongdongnan Basin, northern South China Sea

2018 ◽  
Vol 168 ◽  
pp. 17-26 ◽  
Author(s):  
Jiliang Wang ◽  
Shiguo Wu ◽  
Xiu Kong ◽  
Benjun Ma ◽  
Wei Li ◽  
...  
Keyword(s):  
Fluid Flow ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Qiongdongnan Basin ◽  
Cold Seep ◽  
China Sea ◽  
Subsurface Fluid

scholarly journals Gas Hydrate Accumulation and Occurrence Associated with Cold Seep Systems in the Northern South China Sea: An Overview

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Wei Zhang ◽  
Jinqiang Liang ◽  
Qianyong Liang ◽  
Jiangong Wei ◽  
Zhifeng Wan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Northern South China Sea ◽  
Cold Seep ◽  
Cold Seeps ◽  
Associated Gas ◽  
China Sea ◽  
Gas Bearing

Studying deep-water cold seep systems is of great significance to gas hydrate exploration due to their close relationship. Various cold seep systems and related gas hydrate accumulations have been discovered in the northern South China Sea in the past three decades. Based on high-resolution seismic data, subbottom profiles, in situ submergence observations, deep drilling and coring, and hydrate gas geochemical analyses, the geological and geophysical characteristics of these cold seep systems and their associated gas hydrate accumulations in the Qiongdongnan Basin, the Shenhu area, the Dongsha area, and the Taixinan Basin have been investigated. Cold seep systems are present in diverse stages of evolution and exhibit various seabed microgeomorphic, geological, and geochemical features. Active cold seep systems with a large amount of gas leakage, gas plumes, and microbial communities and inactive cold seep systems with authigenic carbonate pavements are related to the variable intensity of the gas-bearing fluid, which is usually derived from the deep strata through mud diapirs, mud volcanoes, gas chimneys, and faults. Gas hydrates are usually precipitated in cold seep vents and deeper vertical fluid migration pathways, indicating that deep gas-bearing fluid activities control the formation and accumulation of gas hydrates. The hydrocarbons collected from cold seep systems and their associated gas hydrate reservoirs are generally mixtures of biogenic gas and thermogenic gas, the origin of which is generally consistent with that of deep conventional gas. We also discuss the paragenetic relationship between the gas-bearing fluid and the seafloor morphology of cold seeps and the deep-shallow coupling of gas hydrates, cold seeps, and deep petroleum reservoirs. It is reasonable to conclude that the deep petroleum systems and gas-bearing fluid activity jointly control the development of cold seep systems and the accumulation of gas hydrates in the northern South China Sea. Therefore, the favorable areas for conventional oil and gas enrichment are also prospective areas for exploring active cold seeps and gas hydrates.

scholarly journals Gas hydrate risks and prevention for deep water drilling and completion: A case study of well QDN-X in Qiongdongnan Basin, South China Sea

2014 ◽  
Vol 41 (6) ◽  
pp. 824-832 ◽  
Author(s):  
Liang ZHANG ◽  
Chong ZHANG ◽  
Haidong HUANG ◽  
Dongming QI ◽  
Yu ZHANG ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Deep Water ◽  
Gas Hydrate ◽  
Qiongdongnan Basin ◽  
China Sea
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