层间风化壳岩溶发育演化模式——以塔中川庆EPCC区块奥陶系鹰一段—鹰二段为例  

Evolution modes of interbedded weathering crust karst:A case study of the 1^(st) and 2^(nd) members of Ordovician Yingshan Formation in EPCC block,Tazhong,Tarim Basin

作　　者：冯仁蔚 欧阳诚 庞艳君[2] 李柱正 罗璇 张沁 李世银[4] 周瑜 程亮 

机构地区：[1]中国石油川庆钻探工程公司地质勘探开发研究院 [2]中国石油西南油气田公司勘探开发研究院 [3]中国石油川庆钻探工程公司川东钻探公司 [4]中国石油塔里木油田公司勘探开发研究院

出　　处：《石油勘探与开发》2014年第1期45-54,共10页Petroleum Exploration and Development

基　　金：国家科技重大专项"大型油气田及煤层气开发"(2011ZX05059-001)

摘　　要：基于塔中川庆EPCC区块区域地质背景,结合钻井显示、录井取心、成像测井、地震反射等特征,分析鹰山组鹰一段—鹰二段层间风化壳岩溶发育特征及演化过程。研究表明:不整合面附近溶洞充填与否取决于水动力作用的强弱,水动力与纵向上的岩相分布共同决定了层间岩溶内幕溶洞的发育情况;岩溶单元可划分为高地、次高地、上下斜坡、洼地等一级单元,以及溶峰、陡崖、平台、溶丘等次一级单元,整体呈北西—南东向带状展布;表层风化带仅发育在EPCC区块北部,垂直渗流带在南北厚度各异,季节变动带从南部和中部向北部"相变"为水平渗流带;沉积微相影响岩溶发育但非岩溶旋回划分的决定因素,构造隆升、气候、古水文条件是造成岩溶南北分异的主因;EPCC区块鹰一段—鹰二段层间风化壳岩溶可划分为3期旋回、8级次旋回,最终残留第3期旋回(第5~8级次旋回),其中第5、8级次旋回从南到北具有明显"同期异相"特征。The evolution of interbedded weathering crust karst on the top of the Ordovician Yingshan Formation were described based on the geological background, oil and gas show while drilling, core, log imaging and seismic reflection features in the Tazhong area. The study shows that： Filling features of dissolved caves near unconformities depend on the hydrodynamic strength, which, together with the vertical lithofacies, determines the development degree of the interbedded karst. Karst units are classified into several first order units, namely highland, sub-high, slope, and sub-sag, and some secondary units such as dissolved peak, cliff, platform, and dissolved mound, stretching like a strip from northwest to southeast on the whole. The surface weathering zone developed only in the north of the EPCC block, the vertical vadose zone has different thickness in south and north, while the seasonal variation zone changes to horizontal vadose zone from south to north. Sedimentary microfacies affects karst development, but it is not the deciding factor of karst cycle classification, the main factors resulting in the karst difference between south and north are structural uplift, climate, and ancient hydrological conditions. Three cycles and eight secondary cycles are identified in the interbedded weathering karst in Member Yingl-Ying2 in the EPCC block, among them, the third cycle, including the fifth to the eighth secondary cycles, remains, and the fifth and eighth secondary cycles show obvious ＂different facies＂ features from south to north.

关 键 词：塔中 川庆EPCC区块 奥陶系 层间岩溶 岩溶旋回 发育模式 

分 类 号：TE122.1[石油与天然气工程—油气勘探]