Enhancing Fault Mapping in Complex Structure with Applications of Ultra-Deep Azimuthal Resistivity Imaging

Heavily faulted reservoirs require clear understanding of their structures for optimal development and reservoir management. Relying on seismic data has been the main enabler for identifying faulted regions, however, seismic data resolution is impacted by the throws (shifts) of the faults, resulting in many faults being undetected. This study discusses the use of Ultra-Deep Resistivity (UDAR) image in accurate detection of faults, and how these results can gap the uncertainties of fault mapping. A candidate well, located within a heavily faulted area, has been selected for the utilization of UDAR imaging. The well provides a unique opportunity for mapping the congestion of faults and their potential extension towards the surrounding areas. The objectives of utilizing UDAR imaging include providing a comprehensive insight on the complex structure of the area, and assisting the geo- steering in a challenging trajectory crossing several faults. The UDAR imaging results have been benchmarked with resistivity image log and seismic data to identify the areas of uncertainties in faults identification from each data source. The obtained results from the UDAR image log added substantial information and data points for a better understanding of the area. The UDAR results identified several unexpected faults that were not detected previously by seismic data. The tool also estimated the throws (shifts) of each detected fault clearly, while they were not captured by seismic due to limitations in seismic resolution for detecting minor faults with small throws. The picked faults from UDAR have been confirmed with conventional resistivity image tool, as a benchmark approach to confirm their accuracy. Besides fault detection, the tool provided valuable insights on the extension of several fractures, ultimately assisting the lower completion design and compartmentalization of the lateral. Combining the data obtained from seismic, resistivity images, and UDAR image provided a comprehensive view of the complex structure of the area, ultimately assisting the planning of wells, and optimal development in the future. Combining structural data obtained from several sources resulted in a better delineation of complex structures and faulted regions. The paper discusses the process of structural delineation starting from seismic, resistivity images, and finally complimenting the data with UDAR image logs to gap uncertainties. It provides a clear reference for areas with similar challenges by identifying the values and limits of each data source.