膏盐岩油气封盖性研究进展

膏盐岩是全球范围内最为重要的一种油气盖层，越来越多的勘探实例显示膏盐岩油气封盖性差异显著。为加强对这个科学问题的理解，综述了此领域的研究进展。结果表明，膏盐岩的成因主要有膏盐盆和萨布哈两种，分别呈环带状和平行岸线的带状分布。前者分布广、厚度大，最具封盖意义。膏盐岩的封盖机理主要包括物性、超压和塑性三重封闭。膏盐岩的溶蚀在垂向上可划分为4个带：顶部溶蚀带、断层溶蚀带、层内水溶蚀带和底部溶蚀带；平面上可划分为3个区：岩溶高地、岩溶斜坡和岩溶盆地。在评价膏盐岩封盖性时，要多方面综合考虑。首先是内因，即膏盐岩的分布面积、完整度与厚度等。在此基础上再分析溶蚀作用和构造作用（外因）对封盖性的影响。评价的定量化是发展趋势，尤其是溶蚀和构造作用（外因）对膏盐岩封盖性的影响，目前的研究还处于探索阶段，这是今后工作的重点与难点。

Research advances on hydrocarbon sealing properties of gypsolyte/saline rocks

Gypsolyte/saline rocks are one of the most important hydrocarbon cap rocks worldwide.More and more exploration cases indicate that their sealing properties are highly variable from well to well.To better understand the rocks and its implication as cap rocks,we present in this article an overview of the research advances in the industry.It shows that these rocks are mostly originated from evaporitic basins and sabkhas,largely presented themselves as annular rings or bands parallel to shorelines.The rocks of the former origin have been considered ideal cap rocks as they are usually widely distributed and big in thickness.The sealing mechanisms of the gypsolyte/saline rocks may be summarized as favorable physical properties,overpressure and plasticity.The dissolution of the rocks was recorded vertically by four zones:top dissolution zone,fault dissolution zone,intra-layer water dissolution zone and bottom dissolution zone,and horizontally by three zones:karst uplift,karst slope and karst basin.Many factors,such as the distribution area,integrity,thickness and etc.(the internal controlling factors for sealing properties),shall be taken into consideration during the evaluation of sea-ling properties of the rocks.The impacts of dissolution and tectonism (external controlling factors for sealing properties) on the sealing properties of the rocks are then analyzed.Current research is focused more on quantitative evaluation of the sealing capacity of the rocks,especially the impacts of dissolution and tectonism.The research is still in a stage of exploration and it is both challenging and exciting.