含盐盆地地震勘探技术浅析

世界上有58%已发现的商业性油气田与盐系地层有关;在欧亚大陆的含盐盆地,无论属于哪个地质年代的含盐地层均含油气。1990年由埃克森公司在密西西比河谷获得首次盐下油气重大发现以来,对盐岩的勘探技术受到了广泛重视。盐岩具有折射效应强烈、横向变化快速、边缘倾角较陡及存在含流体穴等特点,给地震勘探造成严重影响。对盐岩地震勘探技术及地震模型作了综合分析,对盐上、盐顶、盐内、盐底、盐下等不同盐层部位的常用勘探方法进行了讨论,最后指出了一些正在努力改进的勘探技术或方法。三维成像技术的进步,尤其是三维地震数据的叠前深度偏移和海上大地电磁技术,可提供盐下构造与厚度的准确成像。

Overview of Seismic Prospecting Technology in Salt Basins

There are 58% of discovered commercial oil and gas fields related with salt strata in the world.Every salt-bearing basin is petroliferous in the Euro-Asian continent no matter what geochronologic salt strata it is.A wide attention has been paid to the exploration technology of salt strata since the hydrocar- bon under salt strata was first discovered by Exxon Corp.in Mississippi Valley in 1990.Salt rock is characterized by inten- sive refraction effect,rapid lateral variety,steep edge dips and existing fluid-bearing spaces,which will seriously influence the seismic prospecting result.In this paper,the author com- prehensively analyzes the seismic prospecting technology of salt rock and the seismic models,and discusses common seis- mic methods of prospecting different salt parts that are on,un- der,within,at top and at bottom.Some improving prospecting technology and methods are also put forward.Development and progress of 3-D imaging technology,particularly the tech- nology of depth-migration-before-stack of 3-D seismic data and the MT technology in the sea,can indicate the correct imaging of structures and thickness under salt strata.