Fractured Network Evaluation Across Two Nearby Wells in a Carbonate Reservoir Using Borehole Image Logs: A Case Study in Onshore Abu Dhabi

Understanding fracture connectivity in carbonate reservoirs plays a critical role in optimizing well placement, production performance and stimulation design. This study presents a focused evaluation of potential natural fracture networks encountered in two closely spaced horizontal wells, X and Y, targeting the upper drain interval of the ‘Target A’ formation. The wells, drilled approximately 500 m apart, exhibited similar borehole image log responses characterized by sharp, planar discontinuities. This study aimed to assess the likelihood that the observed features represent partially filled or open fractures and to evaluate the possibility of lateral continuity of these features across the two wells, aligned along a regional WNW–ESE structural trend. The approach involved a comparative interpretation of borehole image logs acquired from the two wells. High-resolution resistivity-based image logs from LWD were processed to extract fracture orientations and dips. Image features were classified using standard criteria such as sinusoidal shape, continuity, aperture sharpness and resistivity contrast. Only those features meeting key fracture-identification parameters were retained for further structural analysis. A rose diagram and Schmidt plot analysis were conducted to understand dominant fracture sets and their orientation. Additionally, the spatial separation and relative positions of the two wells were incorporated into a 3D subsurface structural model to evaluate the likelihood of these fractures forming part of a continuous regional system. Both X and Y wells displayed multiple sharp, planar features across similar stratigraphic intervals in the upper ‘Target A’ drain. These features exhibited high-angle dips and were aligned consistently with a dominant WNW–ESE orientation, suggesting structural control by regional tectonics. The resistivity contrast and sharpness of these features indicate partial mineral infill, supporting their classification as partially filled natural fractures. The orientation similarity between the wells, despite the 500-m spacing, indicates a potential regional fracture trend with lateral continuity. This hypothesis is further supported by the alignment of the features with regional fault and stress orientation trends previously mapped in the field. The identification of a potentially continuous fracture network across wells X and Y has important implications for reservoir modeling, development planning, and future well orientation. If validated through additional data, such as pressure interference testing or production logging, this fracture network could represent a preferential flow path, enhancing reservoir connectivity and influencing drainage patterns. For development planning, this could support more effective infill drilling strategies or inform the placement of injectors and producers for optimized sweep efficiency and enhance the recovery factor. From a geomechanical standpoint, the WNW–ESE trending fractures should be incorporated into future reservoir geomechanical models and hydraulic fracturing simulations. This study demonstrates the critical value of borehole image logs in recognizing fracture trends and building confidence in early-stage field development assessments. The findings serve as a foundation for proposing a broader integrated study of fracture characterization and its influence on well performance in this structurally complex carbonate reservoir.