The Utilization of High-Definition Borehole Images to Determine Fracture Properties and Their Relative Age for Fractured Basement Reservoirs

Fracture data from borehole images has been a critical portion of well data for the fractured granite basement reservoir characterization for long in Vietnam. However, acquiring good quality electrical borehole images can be often challenging due to extremely high formation resistivity and also abnormal wide range of resistivity spectrum within the basement. A new imaging tool was introduced in the local basement wells recently to provide highdefinition full-coverage electrical borehole images. The enhanced borehole images allowed better interpretation confidence and accuracy for fracture properties for the basement reservoirs. There are a few case studies presented in this paper to illustrate some key improvements and applications of this new image data. First of all, the image quality enhancement from the high-definition tool is shown in comparison with conventional image data acquired from the same basement formation. Secondly, a case example is presented to show that accurate fracture properties derived from the high-definition images can help to better predict permeable zones with validation from dynamic data in the same well. Thirdly, examples on how to interpret relative fracture ages for the various sets of fractures developed in the basement using the new images are also discussed. Such fracture information potentially allows better understanding of the fracture/fault development as well as assisting geoscientists to build proper fracture models in the basement.