Large-Scale Structural and Centimeter-Scale Sedimentary Analysis Based on Enhanced Dip and Image Patterns - A Case Study of Well-B

Imaging logging, renowned for its high resolution, is widely utilized to identify small-scale geological features such as fractures, vugs, and sedimentary structures, especially for identifying centimeter-scale sedimentary characteristics like current beddings. However, during the actual interpretation process, large-scale structures exceeding ten or twenty meters are frequently encountered. At such cases, imaging interpretation needs to be conducted at both large and small scales to accurately identify or deduce the true geological features. This paper comprehensively enhances the classic colored dip patterns and the classified imaging log patterns. By introducing more patterns and assigning detailed geological meanings, these enhanced patterns are successfully applied to Well-B which is drilled in a complex structural area. Based on the dip and image patterns, in combination with conventional logging data, at the large scale, structural zones are divided, large and small faults, fault zones, and unconformities are identified. At the centimeter scale, sedimentary features such as cross-beddings are identified, paleo-current directions are inferred, and sedimentary facies analysis is carried out. The authors emphasize the significance of considering the scale during the imaging interpretation process to avoid the pitfall of “focusing solely on details while neglecting the whole” and “only seeing the images but missing the dips”, and vice versa. The enhanced dip and imaging patterns, along with the introduced relevant charts, analysis processes, and inference methods, provide valuable references for similar imaging log interpretations in the future.