沉积学研究中的地层倾角测井资料解释

地层倾角测井资料中包含着丰富的地质信息，它不仅可以反映地层的岩性界面，而且对于地层的时间当量层理面也有所响应，即当地层的沉积构造发生变化时，与之相应的地层倾角和侧向也将随之发生变化。在地展倾角矢量图上，根据倾角矢量随深度的变化关系可以将其划分为五种颜色模式:蓝模式、红模式、绿模式、黄模式和白模式，这五种颜色模式分别反映不同的沉积构造。砂岩体在倾角矢量图上主要表现为三种矢量图模式:ａ.古水流模式-水流层理、顺流加积和进积；ｂ.底线模式-侧向加积和冲蚀接触；ｃ.地层形状模式-压实模式、古水流模式和底线模式可以指示以水流为其搬运介质的沉积砂体，如河道沉积和三角洲沉积，压实模式可以指示岩礁或砂坝。综合分析地层倾角矢量图、地层倾斜方位频率图和画有横向对比线的地层倾角极板曲线图可以研究如下所述的地层沉积学问题:１）地层的形状特征，如地层的厚度、地层的延伸方向和延伸范围、地层面形状。２）地层界面特征，即相邻地层的接触关系，是渐变接触还是突变接触。３）层理特征，如块状层理、纹层状层理和非均质层理。４）沉积旋回和韵律。５）古水流方向和砂体加厚方向。６）砂体微相，即当大的沉积环境（如三角洲沉积环境）已知的条件下，可以识别（如分流河道砂体、河口坝砂体等)砂体微相。

Interpretation of Dipmeters in Sedimentological Research

There is a lot of geological information in dipmeters. Not only can lithological boundaries be respondded, but also bedding planes of time equivalent can be detected by dipmet6rs. In other woads,when sedimentary structure of a zone chanses, the dip angle and azimuth of the zone wil change.According tO the relationship of dip vectors with depth, five grouch of dip Patterns (color Patterns)are defined on odpole plot, i. e., blue pattern, red pattern, green pattern, yellow pattern, and white pattern. These patterns stand for different sedimentary structures.Sand bodies contsin three major groupe of dip patterns: peleocurrent indscatort (current boding, downsttea accration and progradation); thalweg indicators (lateral accretion and erosional contact); and topogtsphic indicators (compection).Paieocurrent and thalweg indicators are used in current domiinant sand bodies such as fluvial channes and deltas.The compaction indicators used in defining topograhic features such as reefs and bars.The following edimentolodcal features can be studied by integrated analysis of tadpole plots, azimuth plots, and Pad resistivity curves with correlation lines:(1) Bed shape: bed thickness, lateral dimension of beds, and bedding Plane. (2) Nature of bed boundries:the transition from one lager to another can either be abrupt or gradual. (3) Bedding factores, several types of internal organization can be recognized, such as massive bedding,laminated bedding, and imbricated bedding. (4) Rhythms and cycles. (5)Paleocurrent direction and thicking direction of sand body. (6) Major sand bodies. When sedimentary environment (such as delta) is known, sandbodies (distributary channel or mouth bar sands, etc. ) can be recognized.