东非鲁武马盆地油气地质特征与勘探前景

近几年，在东非海上相继发现了多个巨型天然气田，使得东非莫桑比克和坦桑尼亚可能成为全球 新的天然气生产中心。查阅多项最新外文资料，认为东非的天然气来自同一个盆地---鲁武马（Ruvuma）盆地。该盆地为全球少数几个未开展大规模勘探的古近纪-新近纪三角洲沉积盆地之一，近期的天然气勘探发现证实该盆地具有巨大的资源潜力与良好的勘探前景，但该盆地勘探程度低，对天然气形成与聚集规律的认识还处于初级阶段。目前推测烃源岩为4 套，天然气主要来源为中生代地层（以侏罗系为主）的热成因气，也可能存在古近系的生物成因气；主要储层为古近系古新统、始新统、渐新统和新近系中新统的三角洲砂体，潜在储层包括二叠系-三叠系碎屑岩，上、中侏罗统碎屑岩和碳酸盐岩以及白垩系碎屑岩和碳酸盐岩；在全球海侵的背景下，上白垩统页岩为区域盖层，古近系和新近系的层间页岩为局部盖层，侏罗系和白垩系期间在局限海沉积环境下的页岩可作为潜在盖层。鲁武马盆地为下部裂谷沉积体系、上覆三角洲沉积体系的模式，具有极佳的油气赋存条件。对该盆地资源潜力的认识将有助于指导我国在东非的油气合作与勘探目标优选。

Petroleum geologic characteristics and exploration prospect in Rovuma Basin,East Africa

In recently years, several giant natural gas fields have been found in East Africa, which makes Mozambique and Tanzania in East Africa become the focus of the gas generation in the whole world. According to new foreign statistical data, it is believed that the gas in East Africa are all from a same basin-Rovuma Basin. Rovuma Basin is one of the few unexplored Tertiary delta sedimentary basins in the world. Recent natural gas exploration findings confirm that the basin has huge resource potential and favorable exploration prospect, but the exploration degree is low, and the knowledge of natural gas generation and accumulation is still at the primary stage. It is supposed that there are four set of source rocks, the gas is mainly of thermogenic gas in Mesozoic strata, and Paleogene biogenic gas may also exist. The main reservoirs are delta sand bodies in Paleocene, Eocene and Oligocene of Paleogene and Miocene of Neogene. The potential reservoirs include Permian-Triassic clastic rocks, Upper-Middle Jurassic clastic rocks and carbonate rocks and Cretaceous clastic rocks and carbonate rocks. In the background of global transgression, Upper Cretaceous shale is regional cap rock, Paleogene and Neogene layer shale is local cap rock, and during Jurassic and Cretaceous, shale can act as potential cap rock in the sedimentary environment of restricted sea. Rovuma Basin is a composite basin of lower rift deposit and upper delta sediment, which has excellent hydrocarbon accumulation condition. The study of Rovuma Basin will be in favor of guiding the international corporation in east Africa, and help the decision of oversea energy strategic target.