First Use of Ultra-Deep Resistivity 2D Deep Azimuthal Images to Identify Reservoir Sweep in a Mature Waterflood of Al-Shaheen Field

The Al Shaheen field has been on production for 25 years and is developed using waterflood and ERD wells, some of which are openhole. Production logging Tools are occasionally required to assess waterflood performance, and the implementation of appropriate mitigation steps. Wellbore architecture and offshore facility limitations make conventional production logging challenging. Therefore to identify swept zones or non-conformances an ERD producer and injector, a novel data acquisition plan based on Ultra-deep resistivity LWD measurements and more conventional open hole measurements was designed to overcome these challenges. Ultra-deep directional resistivity measurements recorded in the injector well were used to map the reservoir structure and fluid distribution up to 100 feet above and below from the injector well. In addition to time lapse resistivity logging, a novel 2D deep azimuthal imaging using extended set of ultra-deep directional resistivity measurements with 3D sensitivities were used to identify movement of fluid in horizontal direction towards the producer well. Full 3D modeling of deep directional resistivity responses was performed before the data acquisition to evaluate sensitivities and signatures of invaded fracture swarms of variable fracture density on measurements and real-time interpretation based on 1D inversions.

The 2D deep azimuthal imaging using the extended 3D set of ultra-deep directional resistivity measurements provided resistivity maps used to identify the fluid fronts and evaluate movement of fluids in lateral direction and heterogeneities not only above and below but also left and right up to 100ft away from the wellbore. The identified flooded zones were consistent with time-lapse resistivities. The 3D modeling and 1D inversion helped to understand patterns in real-time deep directional resistivity interpretation. Detailed analysis of resistivity responses and original while drilling images confirmed identified fracture swarm zones. Besides overcoming challenges with conventional production logs, the methodology provides a unique 3D view of the reservoir from LWD logs at the scale of inches to 100ft.

The case study demonstrates the potential of newly developed deep azimuthal 2D imaging using ultra-deep directional resistivity data to refine the 3D structural interpretation and evaluate the fluid distribution up to 100 feet away from the injector well. This information will be critical to build for the first time consistent 3D interpretation from the wellbore to reservoir scale, calibrating 4D seismic in challenging Middle East carbonates reservoir and bridging the gap between the time-lapse conventional resistivity logs and 4D seismic.