New Image Process Technique Reveals New Hidden Formation Structures Using Anisotropy and Dip Images

摘要

A new image processing technique has been developedin which resistivity-based image data is used to createnew images based on anisotropy. The advantage ofimaging tools is that they can provide high resolutiongeological information in 3 dimensions (i.e., verticallyand azimuthally around the borehole). Therefore, it ispossible to interpret this data in more detail than withlogs that produce only depth-associated information.Consider a resistivity imager that takes an array ofmeasurements around the borehole. This information iscomposed of an array of measurements much like thepixels in a photograph. These pixels can be displayed sothat the position of the points is aligned with depth inthe vertical axis and angular displacement in thehorizontal axis in a frame of data. Based on the spatialorientation of the data, it is possible to upscale thesepoints to determine the up-scaled horizontal (Rh) andvertical resistivity (Rv) associated with these points.The entire frame of data is resolved into a single-valuedpoint with anisotropy. By repositioning the center pointof the frame, a new anisotropy is then determined andan image log is created by processing the entire image.This upscale anisotropy image assumes that theanisotropy is relative to the borehole. In another step,the axis of the data frame is rotated until a minimumanisotropy is determined, resulting in anisotropy and adip value associated with that point. As a result, both ananisotropy and dip image can be created by processingthe entire image in this manner.These new anisotropy and dip angle images open up anentirely new way of analyzing image data and revealhidden structures that are not readily apparent in theoriginal image. This new image processing method isused to analyze resistivity image logs, and the resultsshow dramatic new images that enhance theunderstanding of the geologic structures.