东海盆地椒江凹陷古新统烃源岩地球化学特征及生烃历史

为揭示东海盆地椒江凹陷油气勘探潜力，基于地球化学和盆地数值模拟方法对古新统月桂峰组、灵峰组和明月峰组烃源岩开展生烃能力和生烃过程研究.结果表明，月桂峰组和灵峰组泥岩有机质丰度高，以Ⅱ型干酪根为主，为水生生物和陆源高等植物混合来源，且形成于偏还原环境.夹有薄层炭质泥岩和煤的明月峰组泥岩有机质丰度低，以Ⅲ型干酪根为主，为陆源高等植物来源且形成于氧化环境.古新世至始新世，椒江凹陷大幅度沉降且古热流较高，是古新统烃源岩热演化程度增加的主要时期.受埋藏史和成熟度史共同控制，月桂峰组和灵峰组经历了2次生烃作用，第1次发生在古新世晚期，第2次发生在始新世中期至晚期，生烃强度高.明月峰组仅在始新世末期经历了1次生烃作用，生烃强度低.椒江凹陷古新统烃源岩生烃潜力强，具有广阔的油气勘探前景，应围绕生烃中心尤其是月桂峰组生烃中心选择形成于中新世之前的有效圈闭进行钻探. 

Geochemical Characteristics and Hydrocarbon Generation History of Paleocene Source Rocks in Jiaojiang Sag,East China Sea Basin

In order to understand oil and gas exploration potential of Jiaojiang sag in the East China Sea basin, hydrocarbon generation capacity and process of the Paleocene Yueguifeng (E₁y), Lingfeng (E₁l) and Mingyuefeng (E₁m) Formations were investigated using geochemical analysis and basin modeling. Results show that E₁y and E₁l mudstones are high-quality source rocks with high organic matter abundance and type Ⅱ kerogen, which is dominated by both aquatic organisms and terrestrial higher plants deposited in sub-reduced environment. E₁m mudstone interbedded with thin carbonaceous mudstone and coal is poor-quality source rock with low organic matter abundance and type Ⅲ kerogen, whose organic matter was derived from terrestrial higher plants under oxidized environment. Great subsidence and high paleo-heat flow from the Paleocene to the Eocene made it main period for increasing thermal maturity of source rocks. Controlled by burial and maturity histories, the E₁y and E₁l formations experienced two hydrocarbon generation stages, which took place in the Late Palaeocene and in the Middle to Late Eocene, respectively, and is characterized by high hydrocarbon generation potential. The E₁m Formation only had one hydrocarbon generation process at the end of Eocene, which is characterized by low hydrocarbon generation potential. The Paleocene source rocks in the Jiaojiang sag have strong hydrocarbon generation capacity, so the future oil and gas exploration should focus on hydrocarbon generation center, especially that of the E₁y Formation, and select effective traps formed before the Miocene.