台湾海峡盆地西部坳陷油气地球化学特征及其勘探远景评价

Near-surface oil and gas geochemical characteristics and exploration prospect of the western depression of Taiwan Strait Basin

台湾海峡盆地一直被认为具有良好油气远景,然而以往的研究都是基于沉积学、地球物理学等方面的成果,尚缺少直接的钻探资料来证明其油气资源,或油气地球化学资料证明该区油气渗漏体系的存在与否。笔者拟通过该区的油气地球化学勘探普查,探索该区油气渗漏体系的存在性及其地表响应特征,为进一步的海域油气详查提供有力证据。结果表明,各项油气化探指标在该区均有一定的地表响应,为低背景场反映,表明研究区下伏地层中存在烃类渗漏现象;通过化探指标有效性遴选及综合异常评价,在九龙江凹陷和晋江凹陷共遴选了7个异常区,且均具有较好的油气远景,是下一步油气详查的优选靶区。

Taiwan Strait Basin is commonly considered to be a good petroleum?bearing area. However, the former studies were all fo?cused on the data from sedimentology and geophysical exploration, and no direct evidence from drilling or petroleum geochemistry can prove the existence of any economic oil or gas reservoirs in areas supposed to have good petroleum prospects. In this study, submarine near?surface geochemical exploration for oil and gas was conducted to reveal whether the hydrocarbon seepage is existent in these areas in the hope that it could further provide direct evidence for the existence of petroleum reservoirs at subsurface. The result indicates that the hydrocarbon seepage system do exist in this area, and the near?surface response of hydrocarbons in the sediments further indicate that the study area has a good petroleum prospect.