无为盆地周冲村组膏盐层地震响应特征研究及其油气地质意义

Seismic response characteristics of the gypsum-salt layer in the Zhouchongcun Formation of the Wuwei Basinand its petroleum geological significance

膏盐层作为油气田的主要盖层,对油气藏封存具有重要意义。文章在无为盆地开展二维地震勘探工作的基础上,运用井震联合对比分析方法,总结区域内膏盐层的地震响应特征,较细致地刻画无为盆地周冲村组膏盐层的厚度和空间分布规律。研究结果表明:膏盐层厚度与地震振幅属性具有一定的正相关性,地震振幅越强,膏盐层厚度越大;无为盆地膏盐层在纵向上厚度变化范围为45~540 m,横向上在盆地核心区和凹陷区膏盐层发育较厚,主体介于300~500 m之间,在盆地构造高点位置膏盐层发育较薄,主体介于50~150 m之间,膏盐层分布特征与无为盆地构造总体呈现“低厚高薄”规律。文章为无为盆地天然气和页岩气勘探突破提供了技术保障。

The gypsum-salt layer,as the main cap rock of oil and gas fields,is of considerable importance for the sealing of oil and gas reservoirs.On the basis of a 2D seismic exploration in Wuwei Basin,the seismic response characteristics and spatial distribution regularity of the gypsum-salt layer in Zhouchongcun Formation were analyzed using the integrated analysis method of well logs and seismic data.Results indicate a certain positive correlation between the thickness of the gypsum-salt layer and the seismic amplitude attribute.A thick gypsum-salt layer leads to a strong seismic amplitude.The thickness of the gypsum-salt layer varies from 45 to 540 m in the longitudinal direction.Horizontally,the gypsum-salt layer is relatively thick in the core and depression areas of the basin,and the main part is between 300 and 500 m.The gypsum-salt layer is relatively thin in the structurally high position of the basin,and the main body is between 50 and 150 m.The distribution characteristics of the gypsum-salt layer generally show that the low tectonic position corresponds to a thick gypsum-salt layer,and the high tectonic position corresponds to a thin gypsum-salt layer.This study provides a technical guarantee for the breakthrough of natural and shale gas exploration in the Wuwei Basin.