深层-超深层白云岩储集层:机遇与挑战

Deep or super-deep dolostone reservoirs:Opportunities and challenges

深层—超深层白云岩储集层是未来油气勘探的重要领域和目标,是潜在的优质油气储集体或储集层。查明白云岩的成因、孔隙发育与保存机理以及流体性质与演化路径,建立符合实际地质状况的储集层地质模型,对于预测深层—超深层白云岩储集层的分布规律是非常重要的。疏理了白云岩成因的几个核心问题的现状与发展趋势,指出了白云石化作用模式的演变过程和发展方向,提出了建立深层—超深层白云岩多阶段动态演化模式应考虑的问题。中国三大克拉通盆地(四川盆地、塔里木盆地和鄂尔多斯盆地)深层—超深层赋存丰富的白云岩,并且已经有一些重要的油气发现,为开展深层—超深层白云岩油气勘探提供了好的机遇,但深埋藏、多期构造改造、叠加和复杂的流体演化历史也是此项研究重要的挑战。

Deep or super-deep dolostone reservoirs tend to be the important exploration field and targets in the future. Resulting from dolomite replacement and dissolution,abundant volumes of secondary porosity were commonly produced,which made the dolostones the potential high-quality petroleum reservoirs. In this context,it is imperative to reveal the mechanisms of dolomitization,porosity generation and preservation,as well as to investigate responsible fluid attributes and evolution pathay,then to establish reliable geological reservoir models. Under documenting the core issues related to ＂dolomite problems＂,this review listed the major dolomitization models,present bandawagons,and main concerns in future dolomite studies,particularly for the deeply-buried dolostones experiencing complicated tectonic and fluid modifications. In China,abundant dolostones occur at great depths of 〉6500m in the three largest cratonic sedimentary basins（ Sichuan Basin,Tarim Basin and Ordos Basin）,which have contributed numerical commercial petroleum reserves and provided favourable opportunities for petroleum exploration in deep or super-deep formations. However,big challenges would also exist due to the great burial depths,multiplephase,superimposed tectonic overprinting and complicated history of basin-fluid evolution.