高校地质学报2017，Vol.23Issue(4)：725-736,12.DOI:10.16108/j.issn1006-7493.2017068
长江三角洲启东地区全新统气源岩有机地球化学特征及生物气形成的控制因素
Organic Geochemistry of the Holocene Gas-generating Source Rocks and Controlling Factors of Shallow-biogenic Gas in the Qidong Area, Yangtze River Delta
摘要
Abstract
Based on a relatively systematic study of core lithology, paleontology, organic petrology and organic geochemistry, combined with regional geological background, the abundance, types and maturity of organic matter in the two sets of gas-generating source rocks of the ZK01 well, Qidong area, Changjiang (Yangtze) River delta, were investigated. Controlling factors for the formation of shallow biogenic gas in this study were further addressed. Results show that TOC value of the estuary-floodplain facies is between 0.20％and 0.65％with an average of 0.46％, and the chloroform bitumen content averages at 71.71 × 10-6. The TOC value of the shallow marine facies is between 0.19％and 0.52％with an average of 0.34％, and the chloroform bitumen content averages at 65.69 × 10-6. Thus, the organic matter abundance of estuary-floodplain facies is higher than that of shallow marine facies. This implies a higher gas productivity for the source rocks in the estuary-floodplain facies floodplain. Terrigenous organisms take dominance in organic matters of the Holocene gas-source sediments, and lower aquatic organisms are also present. The organic matter types are herbaceous sapropel-humic and herbaceous humic. Organic matters are still in immature stage, with the Ro ranging between 0.50％and 0.65％, an odd even predominance of n-alkanes, and Tmax value below 435℃. The formation of the shallow biogenic gas is mainly controlled by three factors, i.e., geological conditions, material conditions and geochemical conditions. The interaction, influence and supplement of these three factors are conducive to generate and accumulate shallow-biogenic gas.关键词
长江三角洲/启东/全新统/有机地球化学特征/浅层生物气/控制因素Key words
Yangtze River delta/Qidong/Holocene/organic geochemistry/shallow-biogenic gas/controlling factors分类
天文与地球科学引用本文复制引用
冯旭东,林春明,张霞,邓程文,王淑君..长江三角洲启东地区全新统气源岩有机地球化学特征及生物气形成的控制因素[J].高校地质学报,2017,23(4):725-736,12.基金项目
国家自然科学基金项目(41572112 （）
41402092) （）
江苏省自然科学基金项目(BK20140604)联合资助 （BK20140604）
