Dynamic simulation of gas hydrate reservoirs in the Shenhu area,the northern South China Sea

为进一步了解南海北部神狐海域天然气水合物的成藏匹配条件,利用典型二维地震剖面,构建了该区的地质模型,并对其进行了天然气水合物成藏动力学的模拟。研究结果表明:神狐海域具备天然气水合物成藏的温度、压力条件;生物气和热解气的资源潜力巨大,满足水合物形成的气源条件;运移条件优越,有利于天然气水合物的聚集成藏。并提出了该区天然气水合物的成藏模式。The north slope of the South China Sea is structurally characterized by a passive continental margin and has various Cenozoic oil-and gas-bearing depositional basins,where hydrocarbon resources are abundant,and the geological and tectonic settings,the temperature and pressure regimes as well as the methane-generative potential of thick organic-rich sediments are all favorable for the formation of gas hydrate.As a result,this region is also an ideal area for studying gas hydrate accumulations.In order to understand natural conditions of the gas hydrate formation,based on the typical 2-dimensional seismic image of the Shenhu area,a geological model of gas hydrate reservoirs was established and a dynamic simulation of gas hydrate accumulations was carried out as well.The results indicated that the temperature and pressure of the Shenhu area are appropriate for gas hydrate accumulations,source rocks there have a huge gas-generative potential and hydrocarbon migration conditions are favorable,providing an abundant gas source and good pathways for the gas hydrate formation.A forecasting model of the gas hydrate formation was given based on basin analysis,indicating that the Shenhu area is a better prospect area of gas hydrate because of its huge potential of gas hydrate resources.国土资源部公益性行业科研专项(200811014)“天然气水合物成藏的控制因素研究”;国家自然科学基金项目(No.40930845)“南海北部深水盆地油气渗漏系统与天然气水合物富集机制研究”;国家重点基础研究发展规划(973)项目(2009CB219501)“南海北部天然气水合物成藏的气源条件研究”联合资

南海北部琼东南盆地天然气水合物成藏数值模拟

为查明南海北部琼东南盆地生物成因和热成因天然气的资源潜力及其对天然气水合物成藏的贡献,根据琼东南海域天然气水合物调查区典型二维地震剖面,构建了该区的地质模型,并结合区域内岩性、地热和地球化学等参数对其进行了天然气水合物成藏的数值模拟。结果表明:琼东南盆地具备天然气水合物成藏的稳定域范围,稳定域厚度介于220~340m之间;生物气和热解气的资源潜力巨大,满足天然气水合物形成的气源条件;运移条件优越,有利于天然气水合物的聚集成藏。最后根据气体来源及其运移特征讨论了该区域天然气水合物成藏的地质模式

东沙海域smi与甲烷通量的关系及对水合物的指示

硫酸根甲烷界面(SMI)是识别海洋沉积物中天然气水合物赋存(甲烷通量)的一个重要生物地球化学标志.通过对南海北部陆坡东沙海域37个站位浅表层沉积物中孔隙水的SO_4~(2-)和H_2S含量变化和沉积物顶空气甲烷含量的变化等地球化学特性进行分析,研究南海北部东沙海域硫酸根甲烷界面(SMI)的分布情况,通过硫酸根变化梯度估算甲烷通量.研究结果显示,东沙海域存在南部深水区“海洋四号”沉积体和北部浅水区九龙甲烷礁两个水合物有利区域,SMI埋深普遍较浅,指示较高的甲烷通量(3.8×10~(-3)~5.9×10~(-3)mmol/(cm~2·a)),与国际上已发现天然气水合物区的地球化学特征相类似.这种高甲烷通量很可能是由下伏的天然气水合物所引起的,暗示着该区海底之下可能有天然气水合物层赋存