Velocity-porosity relationships in hydrate-bearing sediments measured from pressure cores, Shenhu Area, South China Sea

IOCAS-IR

	Velocity-porosity relationships in hydrate-bearing sediments measured from pressure cores, Shenhu Area, South China Sea
	Lin Lin ; Jun Cao ; Jin Qian ; Jiu-jing Shang ; Wei Zhang ; Jin-gan Lu ; Jin-qiang Liang
发表期刊	China Geology
ISSN	2096-5192
	2022-04-25
出版年	2022
卷号	v.5 期号:02 页码:73-81
文献类型	CNKI期刊论文
摘要	Evaluating velocity-porosity relationships of hydrate-bearing marine sediments is essential for characterizing natural gas hydrates below seafloor as either a potential energy resource or geohazards risks. Four sites had cored using pressure and non-pressure methods during the gas hydrates drilling project(GMGS4) expedition at Shenhu Area, north slope of the South China Sea. Sediments were cored above, below, and through the gas-hydrate-bearing zone guided with logging-while-drilling analysis results. Gamma density and P-wave velocity were measured in each pressure core before subsampling.Methane hydrates volumes in total 62 samples were calculated from the moles of excess methane collected during depressurization experiments. The concentration of methane hydrates ranged from 0.3% to 32.3%.The concentrations of pore fluid(25.44% to 68.82%) and sediments(23.63% to 54.28%) were calculated from the gamma density. The regression models of P-wave velocity were derived and compared with a global empirical equation derived from shallow, unconsolidated sediments data. The results were close to the global trend when the fluid concentration is larger than the critical porosity. It is concluded that the dominant factor of P-wave velocity in hydrate-bearing marine sediments is the presence of the hydrate.Methane hydrates can reduce the fluid concentration by discharging the pore fluid and occupying the original pore space of sediments after its formation.
关键词	Natural gas hydrates (NGHs) Methane hydrate P-wave velocity Porosity Saturation Pressure-core NGHs exploration trial engineering Oil and gas exploration engineering Shenhu Area South China Sea
CNKI专辑号	A;B;
CNKI专辑名称	基础科学;工程科技Ⅰ辑;
CNKI专题号	A011;B019;
CNKI专题名称	地质学;石油天然气工业;
分类号	P618.13
语种	英文;
资助项目(基金）	jointly supported by the National Natural Science Foundation of China (42076072) ; the project of China Geological Survey (DD20160211) ; the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou, GML2019ZD0506)
文献类型	CNKI期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/187446
专题	中国科学院海洋研究所
作者单位	1.GuangzhouMarineGeologicalSurvey,ChinaGeologicalSurvey,MinistryofNaturalResources 2.SouthernMarineScienceandEngineeringGuangdongLaboratory(Guangzhou) 3.InstitutionofOceanology,ChineseAcademyofSciences
推荐引用方式 GB/T 7714	Lin Lin,Jun Cao,Jin Qian,et al. Velocity-porosity relationships in hydrate-bearing sediments measured from pressure cores, Shenhu Area, South China Sea. 2022.