摘要
孔隙性砂岩在应变过程中首先发生应变局域化并形成肉眼不易识别的变形条带(deforrnation band),这与低孔隙性的碳酸盐岩的应变效应迥然不同。实例分析说明,天山南缘库车坳陷后期构造变形强烈,自白垩纪以来构造应变具有南北分带、东西分异的显著特征。结合盆地构造格架以及砂岩物性分布特征,本文提出了该区六类砂岩储层改造的构造样式,并描述了其中砂岩的构造非均质性。其中深层卷入型(3类)主要发育于盆地西部,而浅层卷入型发育于盆地东部,其分布受基底构造、盐煤等滑脱层、近南北向的调节断裂、盆山边界接触方式的控制。除变形条带外,研究发现本区最大埋深大于6500～7000m的白垩系致密砂岩的应变属性亲近灰岩,其由于后期抬升或深层次构造应变将容易导致裂隙的发育,这一点在有效储层预测中值得重视。
Structural strain of porous sandstones, evidently different from that of low porous limestones, will preferentially produce strain localization and form microscopic deformation bands. A case study shows that late structural deformation developed in the Kuqa subbasin in the northern Tarim basin, the southern foot of the Tianshan mountain and were characterized by north-southern zonation with east-western differentiation since Cretaceous. Based on structural deformation framework and sandstone physical features (porosity and permeability), six types of structural deformation patterns, controlling structural heterogeneity of sandstone reservoirs, are presented in this paper. The deep involved structural patterns (three types) and the shallow involved structural patterns principally occur in the western and eastern Kuqa subbasin respectively, which is controlled by basement blocks, salt-coal detachment beds, north-southern adjusting faults and basin-range boundary types as well as stress distribution. Except deformation bands of porous sandstones, the study also shows that structural strain properties of the Cretaceous tight sandstones buried bigger than 6500 similar to 7000m in depth are similar to that of limestones, which will easily produce more effective fractures accompanying late uplift and/or intense structural strain. This consideration is important for prediction of deep buried sandstone reservoirs in the study area.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第10期2320-2330,共11页
Acta Petrologica Sinica
基金
国家973项目(2006CB202304)
中国科学院知识创新工程重要方向项目(KZCX3-SW-147)资助.
