砂砾岩体精细划分与对比新探索

New approach to fine division and comparison of glutenite

通过深入研究东营凹陷北带盐22块砂砾岩体,探索出一套利用常规测井资料可操作的基于沉积动力分析的对比方法。对比岩心及成像测井刻画的沉积剖面与常规测井曲线发现:在测井曲线整体平直的背景上,有2种岩相厚度发育较薄,测井响应明显:代表最大沉积动力的块状巨砾岩相具有高GR、低AC、低CNL的特征,是基准面下降到极低点的沉积响应;代表相对较小沉积动力的平行层理砂岩或砂泥互层相具有(中)高GR、高AC、高CNL的特征,是基准面上升到极高点的沉积响应。以常规测井易识别的岩相"段"代替不易识别的"面"在单井上划分沉积旋回(或基准面旋回);利用高分辨率层序地层学原理实现侧向对比,建立高精度等时层序地层格架。

By deeply researching the glutenite in Yan 22 Area of Northern Zone, Dongying Depression, this paper explores a set of methods to fine division and correlation of glutenite based on sedimentary dynamic analysis and using conventional logging curve. Comparing with conventional logging responses and sedimentary section depicted by core and imaging logging, it is showed that two kinds of lithofaeies have thin thickness and distinctive logging response in the flat background of conventional logging. The massive boulderstone lithofaeies representing the largest deposition power have logging responses of high GR, low AC and CNL. They are the sedimentary responses of base level deseending to very low point. The parallel bedding sandstone and sand-shale interbed lithofaeies representing a relatively small deposition power have logging responses of mid-high GR, high AC and CNL. They are the sedimentary responses of base level rising to very＂ high point. The section easily identified by conventional logging is used to replace the section not easily identified to divide sedimentary cycles （base level cycle） on single well; using high-resolution sequence stratigraphy theory, the lateral comparison of thick glutenite is tan＇led out and high resolution chronostratigraphic sequence framework is established.