摘要
四川盆地东部和南部中、下寒武统广泛发育膏盐岩层系，形成了多种样式的盐相关构造。依据露头、钻井和地震资料分析，认为四川盆地寒武系膏盐岩形成于克拉通内局限台地环境，具有时代老、埋藏深、厚度分布不均、膏多盐少及伴生岩石类型多样等特点。受膏岩和盐岩流动性差异、构造挤压、基底断裂和滑脱作用等多种因素影响，膏盐岩层系相关构造分层性明显。盐上层表现为背斜、推覆体和断块背斜构造；盐层表现为盐枕构造、盐缩颈形成的鱼尾构造和岩盐塑性流动构造；盐下层则表现为受复杂基底断裂控制的叠瓦冲断和背冲断块构造。寒武系膏盐岩为震旦系-下寒武统目的层系的油气聚集提供了优质的封盖条件；同时，膏盐岩自身参与的TSR反应（硫酸盐热化学还原反应）和表生溶蚀也可以有效地改善储层的储集物性。更重要是，寒武系膏盐岩作为区域滑脱层对盐上和盐下震旦系-下古生界构造变形起着重要控制作用，形成一系列含油气构造圈闭。从盐相关构造的发育特点来看，鄂西-渝东区的盐下断背斜和川东南地区的盐上断背斜是有利的勘探目标。
Abstract
Gypsolyte-salt layers of the Middle-Lower Cambrian are widely developed in the southern and eastern Sichuan Basin,resulting in a variety of salt-related structures.Analyses of outcrop,drilling and seismic data reveal that the gypsolyte-salt layers of the Cambrian in Sichuan Basin formed on restricted intra-craton platform and has the characteristics of old age,deep burial depth,uneven thickness,more gypsolyte and less salt,and various associated rock types.The gypsolyte-salt related structures show obvious layering due to the differential gypsolyte and salt mobility,tectonic compression,basement faults,and detachment,.The post-salt structures are mainly anticlines,thrust nappes and faulted-anticlines.The structures within the salt layers are mainly salt pillows,tail structures and plastic flow structures.The presalt structures mainly include imbricate thrusts and pop-up structures controlled by the complex basement faults.The gypsolyte-salt layers of the Cambrian provide good sealing conditions for hydrocarbon accumulation in the Lower Sinian-Lo-wer Cambrian.Meanwhile,they also can improve reservoir quality through TSR and supergene dissolution that they are involved.Even more important,as a region detachment layer,the gypsolyte-salt rock plays an important role in the structural deformation of the post-salt and pre-salt Sinian-Lower Paleozoic,resulting in a series of hydrocarbon traps.According to the characteristics of gypsolyte-salt related structures,the pre-salt faulted anticlines in western Hubei-eastern Chongqing and post-salt faulted anticlines in southeast Sichuan are the favorable exploration targets.
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