Logging Response Characteristics of Gas Hydrate Formation in Shenhu Area of the South China Sea

分析了南海北部神狐海域含天然气水合物沉积层声波速度及密度的分布特征和变化规律,并通过对比dSdP 84航次570号钻孔含天然气水合物层段测井资料,总结出神狐海域含水合物地层的测井响应规律特征:神狐海域含水合物地层存在着明显的高声波速度、低密度特征,地层密度随声波速度的变化并不是单一的反比例关系,总体趋势上随声波速度的升高而降低;含水合物地层高声波速度值主要集中在197--220 M段,饱和度值在15%--47%之间,低密度值集中在200--212 M段,分布在水合物饱和度大于20%的地层内;含水合物地层声波速度平均值为2 076 M/S,其上覆和下伏地层的声波速度平均值为1 903 M/S和1 892 M/S,所对应的地层密度值分别为1.89 g/CM3、1.98 g/CM3和2.03 g/CM3,声波速度受孔隙度和饱和度的共同影响,地层密度受水合物饱和度影响较大;从水合物上覆地层到声波速度最高值段,声波速度值增加了9.1%,相对应的地层密度值减少了4.55%,从水合物声波速度最高值段到下伏地层,声波速度值减少了8.86%,相对应的地层密度值增加了7.41%。这些测井响应特征,可用来识别地层中天然气水合物,并可以用来计算水合物的饱和度,同时结合其他地质和地球物理资料,确定水合物层的厚度、分布范围,计算天然气水合物的资源量。With analysis of the distributing feature and the changing law of the sonic velocity and density of sediments with gas hydrate in Shenhu Area of the South China Sea,by comparing with logging data of gas hydrate formation at Site 570 of DSDP 84,the logging response characteristics of gas hydrate formation in Shenhu Area were conducted.The results show that:(1)Sediments with gas hydrate in Shenhu Area have the clear features that the sonic velocity is high and density is low,and the density is generally decreased with the increasing of the sonic velocity.(2)The high sonic velocity section in sediments with gas hydrate is in the depth of 197 to 220 m,and the low density section is in the depth of 200 to 212 m;the value of saturation is in the range of 15%to 47%.(3)The average sonic velocities of sediments with gas hydrates and the overlying strata and underlying strata are 2,076 m/s,1,903 m/s and 1,892 m/s,respectively,and the corresponding densities are 1.89 g/cm3,1.98 g/cm3 and 2.03 g/cm3,respectively;sonic velocity is effected by porosity and saturation,and density is greatly influenced by saturation;(4) The sonic velocity increases by 9.1% from the overlying strata of hydrates to the maximum-value section,and the corresponding density decreased by 4.55%;the sonic velocity decreases by 8.86% from the maximum-value section to the underlying strata of hydrates,and the corresponding density increases by 7.41%.The logging response characteristics can be used to identify the existence of gas hydrates and to calculate the saturation of gas hydrate,furthermore,to provide accurate area and thickness of gas hydrate zone for calculating gas hydrates reserves with combination of other geological and geophysical data.中国科学院边缘海地质重点实验室项目(MSGL08-03);国家重点基础研究发展计划(2009CB219508

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

The Seismic Detecting Technique on Gas Hydrates Based on Wave Impedance Inversion

天然气水合物作为特殊的地质体,可以有效地粘结碎屑颗粒,降低沉积物孔隙度,它的存在改变了地层沉积物的物理性质,造成天然气水合物与围岩速度反差较大,从而与围岩之间存在明显的波阻抗差。为了对地层中是否有天然气水合物赋存进行地震检测,对南海北部神狐海域的天然气水合物赋存区域的地震资料进行波阻抗反演分析,结果显示波阻抗反演方法能够作为探测天然气水合物的一种技术手段,研究区天然气水合物矿体的波阻抗呈高值分布特征,波阻抗值约为3 850--3 960 g/CM3.M/S。综合分析认为,波阻抗反演方法能够用于天然气水合物的地震探测、储层分析和综合研究工作中,反演结果可以为天然气水合物储量计算提供比较准确的矿体面积和厚度参数。As specific geologic body,gas hydrate can cement effectively clastic particles and reduce porosity of deposition,so its presence changes physical property of the sedimentary strata and results in the difference of seismic-wave velocity between gas hydrate and the surrounding rock,and there exists obviously wave impedance difference.In order to detect the presence of sediments with gas hydrate,seismic data of gas hydrate zone in the Shenhu area of the northern South China Sea were used in the wave impedance inversion through practice,testing and summary.Wave impedance inversion method is considered as a kind of good seismic detection technique for identification of gas hydrates,meanwhile,the wave impedance of gas hydrate zone shows high value in the study area,and the wave impedance value is about 3,850-3,960 g/cm3·m/s.All the results suggested that wave impedance inversion can be used for detection,reservoir analysis and comprehensive research of gas hydrates.The wave impedance inversion results can provide comparatively accurate area and thickness parameters of gas hydrate zone for reserves calculation.国家高技术研究发展计划项目(2006AA09A202);国土资源部公益性行业科研专项项目(200811014);国土资源部海洋油气资源与环境地质重点实验室资助项目(MRE200911);国家重点基础研究发展计划项目(2009CB219502

中国海及邻近区域碳库与通量综合分析

中国海总面积约470万平方公里,纵跨热带、亚热带、温带、北温带等多个气候带.其中,南海北依\"世界第三极\"青藏高原、南邻\"全球气候引擎\"西太平洋暖池,东海拥有全球最宽的陆架之一,跨陆架物质运输显著,黄海是冷暖流交汇区域,渤海则是受人类活动高度影响的内湾浅海.中国海内有长江、黄河、珠江等大河输入,外邻全球两大西边界流之一的黑潮.这些鲜明的特色赋予了中国海碳储库和通量研究的典型代表意义.文章从不同海区（渤海、黄海、东海、南海）、不同界面（陆-海、海-气、水柱-沉积物、边缘海-大洋等）,以及不同生态系统（红树林、盐沼湿地、海草床、海藻养殖、珊瑚礁、水柱生态系统等）多层面对海洋碳库与通量进行了较系统地综合分析,初步估算了各个碳库的储量与不同碳库间的通量.就海气通量而言,渤海向大气中释放CO2约0.22Tg Ca-1,黄海吸收CO2约1.15Tg Ca-1,东海吸收CO2约6.92～23.30Tg Ca-1,南海释放CO2约13.86～33.60Tg Ca-1.如果仅考虑海-气界面的CO2交换,中国海总体上是大气CO2的\"源\",净释放量约6.01～9.33Tg Ca-1.这主要是由于河流输入以及邻近大洋输入所致.河流输入渤黄海、东海、南海的溶解无机碳（DIC）分别为5.04、14.60和40.14Tg Ca-1,而邻近大洋输入DIC更是高达144.81Tg Ca-1,远超中国海向大气释放的碳量.渤海、黄海、东海、南海的沉积有机碳通量分别为2.00、3.60、7.40、7.49Tg Ca-1.东海和南海向邻近大洋输送有机碳通量分别为15.25～36.70和43.39Tg Ca-1.就生态系统而言,中国沿海红树林、盐沼湿地、海草床有机碳埋藏通量为0.36Tg Ca-1,海草床溶解有机碳（DOC）输出通量为0.59Tg Ca-1;中国近海海藻养殖移出碳通量0.68Tg Ca-1,沉积和DOC释放通量分别为0.14和0.82Tg Ca-1.总计,中国海有机碳年输出通量为81.72～103.17Tg Ca-1.中国海的有机碳输出以DOC形式为主,东海向邻近大洋输出的DOC通量约15.00～35.00Tg Ca-1,南海输出约31.39Tg Ca-1.综上,尽管从海-气通量看中国海是大气CO2的\"源\",但考虑了河流、大洋输入、沉积输出以及微型生物碳泵（DOC转化输出）作用后,中国海是重要的储碳区.需要指出的是,文章数据是基于中国海各海区碳循环研究报道,鉴于不同研究方法上的差异,所得数据难免有一定的误差范围,亟待将来统一方法标准下的更多深入研究和分析.国家重点研发计划项目(编号:2016YFA0601400);;国家自然科学基金项目(批准号:91751207、91428308、41722603、41606153、41422603);;中央高校基础研究项目(编号:20720170107);;中海油项目(编号:CNOOC-KJ125FZDXM00TJ001-2014、CNOOCKJ125FZDXM00ZJ001-2014)资

南海北部神狐海域沉积物颗粒对天然气水合物聚集的主要影响

An important parameter is the saturation of gas hydrate within the sediment pore for evaluating its impact on energy, climate and environment. So it is significant of understanding which factors affecting the saturation of gas hydrates. There is a good r

The methane hydrate accumulation controlled compellingly by sediment grain at Shenhu, northern South China Sea

An important parameter is the saturation of gas hydrate within the sediment pore for evaluating its impact on energy, climate and environment. So it is significant of understanding which factors affecting the saturation of gas hydrates. There is a good r

多种反演方法在南海北部神狐海域天然气水合物识别中的应用

针对海域天然气水合物储层特征及不同反演方法的特点，对南海北部地震资料进行了多种反演方法的试验及研究，随后对反演结果进行对比分析，并最终提出了适合南海海域天然气水合物勘探的反演方法。中国可再生能源学

南海北部神狐海域AVO属性反演及其对天然气水合物的指示

中国地球物理学