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对深海钻探计划(DSDP)岩心的分析揭示了侏罗纪、白垩纪和新生代古海相细粒沉积物沉积速率与总有机碳含量之间的关系。这种关系大多与沉积背景、地质年代和差异压实作用无关,但却受到岩性的强烈影响。对于任何给定的沉积速率,以重量百分此计的总有机碳含量(TOC)从钙质沉积向着钙—硅质沉积、硅质沉积,进而向着黑色页岩而增大。总有机碳含量还随各种岩性的沉积速率而变化。在低沉积速率时,由于沉积物通过有机质分解作用强烈的近表地带时速度较快,总有机碳含量先随沉积速率的增大而增大,但当沉积速率高于某些临界值时,由于碎屑稀释了输入的有机质,总有机碳含量又随沉积速率的增大而减小.然而,因近表有机质分解作用随受埋速率的增高而减弱,故利于生油的有机组分的生油潜势应继续随沉积速率的增大而增大。在总有机碳堆积速率与颗粒堆积速率之间也确立了同样的关系,这些关系既证明了近表有机分解作用的减弱,也证明了碎屑的稀释效应。采用生油岩总有机碳含量的截止值,便可利用这些关系确定海相沉积盆地中生油岩建造的赋存状况。这项研究的结果对于前缘地区的石油勘探可能具有十分重要的意义。在只能获得有限钻井资料的盆地内,可利用它们的地震反射记录或地震等厚线来确定它们的沉积速率。地震记录因此而可用来在钻探之前或钻探初期确定各种前缘沉积盆地的潜在生油岩,以及估算这些生油岩的相对生油潜势。
The analysis of Deepwater Drilling Program (DSDP) cores revealed the relationship between sedimentation rate and total organic carbon content of Jurassic, Cretaceous and Cenozoic fine marine sediments. Most of this relationship has nothing to do with sedimentary background, geologic age and differential compaction but is strongly influenced by lithology. For any given deposition rate, the total organic carbon content (TOC) by weight percent increases from calcic to calcic-siliceous deposits, siliceous deposits and, in turn, toward black shale. Total organic carbon content also varies with the deposition rate of various lithologies. At low deposition rates, total organic carbon content first increases with deposition rate as the sediment passes through the near-surface zone where organic matter decomposes strongly. However, when the deposition rate is above some critical values, As the detritus dilutes the input organic matter, the total organic carbon decreases with the increase of deposition rate, however, because the near surface organic matter decomposition decreases with the increase of burial rate, The potential for oil generation should continue to increase as the deposition rate increases. The same relationship was also established between the total organic carbon deposition rate and the particle build-up rate, both of which demonstrate both the reduction in near-surface organic decomposition and the dilution effect of the debris. Using the cut-off values for total organic carbon in source rocks, these relationships can be used to determine the occurrence of the source rocks in marine sedimentary basins. The results of this study may be of great importance to oil exploration in the frontier areas. In basins where only limited drilling data is available, their seismic reflection records or seismic isobars can be used to determine their deposition rate. Seismic records can thus be used to identify potential source rocks for various frontal sedimentary basins prior to or during drilling and to estimate the relative potential for oil generation of these source rocks.