莫桑比克盆地油气地质特征与勘探前景

PETROLEUM GEOLOGICAL CHARACTERISTICS AND EXPLORATION PROSPECT OF MOZAMBIQUE BASIN

东非海岸地区近几年相继有多个重大的天然气发现,但该地区勘探程度总体较低,天然气的聚集规律仍未得到较好的认识。东非的莫桑比克盆地近年来显示出较为显著的天然气潜力。分析了该盆地构造沉积特征、生储盖、含油气系统等基本油气地质特征,继而评价了其油气资源勘探潜力,以期对我国在东非的油气合作和勘探有利区优选等工作起到指导作用。盆地的构造样式多样,广泛分布有卡鲁岩层。盆地内有3套潜在烃源岩,白垩系海相泥岩提供了主要的天然气来源,最有潜力的为下白垩统Maputo组与Sena组;已证实储层均位于白垩系,为白垩系Domo组砂岩和Grudja组下段砂岩层,白垩系同时也是主要盖层。盆地可以划分为2个含油气系统,分别为白垩系—白垩系含油气系统和二叠系—二叠系煤层含油气系统。赞比西三角洲、北部陆上区域、Beira区、Inhambane区、Palmeira和林波波地堑是勘探有利区。

Substantial natural gas fields have been discovered recently on the East African coast. How ever, the exploration level is still low and the principles of gas accumulation remain unclear there. The Mozambique Basin in East Africa has shown great potential for gas accumulation. Study of structural and sedimentary geology, source rock, reservoir, seal conditions and petroleum system is required for evaluation of hydrocarbon potential and selection of favorable exploration targets in the region. There are various structural styles in the basin and the Karoo stratum is widely distributed. According to the data available so far, there are three sets of potential source rocks, and the Cretaceous marine mud- stone provides the major gas sources. The confirmed reservoirs all occur in the Cretaceous, namely the Domo Formation and the Lower Grudja Formation sandstones. The main seals also occur in the Cretaceous. There are two petroleum systems, namely the Cretaceous Grudja/Domo and the Permian Coal Seams. The favorable exploration areas include the Zambezi Delta, the northern land, the Beira area, the Inhambane area and of the Palmeira and Limpopo grabens.