川中灯影组碳酸盐岩岩溶地层测井响应特征

川中磨溪-高石地区震旦系灯影组受桐湾运动Ⅰ幕和Ⅱ幕的影响,致使灯二段及灯四段顶部遭受风化剥蚀,区内大规模发育的溶蚀孔洞在测井曲线上具有明显的响应特征。通过对研究区的钻井、常规测井及FMI成像等资料分析,将研究区岩溶剖面从上而下分为地表岩溶带、垂直渗流岩溶带、水平潜流岩溶带及深部缓流岩溶带。研究表明,地表岩溶带由风化残余物杂乱堆积而成,水平潜流岩溶带顺层孔洞发育,二者是研究区储层最为发育层位;渗流岩溶带储层较发育,深部潜流带储层不发育。从区域上看,研究区位于古岩溶斜坡带,从南西向北东方向,岩溶作用逐渐增强。

Well logging interpretation of the carbonate karst strata in the Dengying Formation in central Sichuan

Affected by the episodes I and II of the Tongwan movement,the topmost parts of the 2nd and 4th members of the Dengying Formation were subjected to the weathering and denudation,which gave rise to the wide-spread dissolution of the carbonate rocks in the Sinian Dengying Formation in the Moxi-Gaoshi region,central Sichuan. The distribution of hydrocarbon reservoirs may be predicted on the basis of boreholes,well logging and FMI images. The karst sections in the study area may be divided,in a decending order,into surficial karst weathering zone,vertical infiltration karst zone,horizontal subsurface flow karst zone and deep sluggish flow karst zone. The surficial karst weathering zone accumulated by chaotic accumulation of the weathered residual materials and the horizontal subsurface flow karst zone with developed pore spaces are believed to be the best favourable horizons for the development of the reservoir rocks,followed by the vertical infiltration karst zone. Regionally,the karstification becomes progressively stronger from southwest to northeast in the study area in the palaeokarst slope zone.