Integrating Reservoir Mapping and High-Resolution Imaging Technologies Leads to Deliver the Fastest Well with Enhanced Production in an Unconventional Limestone

Well placement in an Unconventional Jurassic Formations of North Kuwait is challenged by poor seismic resolution and high uncertainty in the stratigraphy leading to lateral variability of petrophysical parameters and thickness of the pay zone. The 6-9 feet thick target zone is located at 14,000 feet depth with expected uncertainty in the bed dipping angle. Key technologies were deployed to increase gas production in the tight carbonate formation with depositional uncertainties. A pre-well model was built from existing offset wells to assess the well-placement capabilities. A combination of ultra-deep azimuthal resistivity mapping (UDAR) and gamma ray imaging tools were deployed for accurate landing and steering of the lateral section. The objectives were to keep the well trajectory in the payzone, anticipate and identify any abnormalities in the formation while passing through sub-seismic faults and enable rapid response to sudden changes in formation dip due to structural changes. The ultra-sonic high-resolution imaging (UHRI) tool was utilized across the lateral section to evaluate fractures, faults, and hole shape for optimizing completion design and enhancing production. The 9.25″ landing phase successfully reached the desired target with around 1 degree higher-than-expected formation dipping angle. The target was identified and confirmed by the UDAR and additional logging-while-drilling (LWD) data. The 6″ lateral section was maintained within the target zone, achieving the maximum reservoir exposure passing through several geological features including faults, which were reflected on the resistivity inversions. The combination of deep and short-range measurements enabled successful well placement in the target zone. A spectral gamma ray image helped to identify the clay layers close to the wellbore, whereas the resistivity inversion identified multiple layers on a bigger scale, away from the wellbore. The UHRI helped to facilitate the optimization of completion design and further the field development by identifying 129 features including 125 fractures, 2 faults and 2 bed boundaries. The combination of UDAR with UHRI helped to deliver the fastest well in unconventional Najmah Limestone and supported optimization of the completion design providing enhanced production from the well. This methodology was further recommended to be utilized in upcoming similar well profiles to improve the field development in Unconventional Najmah Limestone reservoir of North Kuwait