Pushing the Limit of Formation Pressures Data Acquisition in HPHT, Sour Tight Carbonates of N. Kuwait Jurassic Gas with Differential Depletion Challenges and Opening New WRM, Development Frontiers

Better understanding of current formation pressure in differentially depleted carbonate and sour reservoirs of North Kuwait's HPHT Jurassic Asset (~12,000 psi, ~285 °F) is critical for Well & Reservoir Management (WRM) and further field development. These tight, heterogeneous reservoirs (porosity <10 %) exhibit significant depletion and pressure variation (~3000-11000 psi) in several zones. Recent shifts in KOC's field development strategy include include horizontal and underbalanced coiled tubing drilling (UBCTD). Due to large pressure variation, precise formation pressure data is essential for well placement, managing stress-related risks with geomechanical models, and ultimately enabling targeted perforation and development strategies. Traditionally, in highly deviated wells, pressure measurements are often excluded due to high risk of differential and mechanical sticking. Furthermore, formation tightness poses challenges in achieving stable pressure readings. To address these limitations and optimize rig time, a fast wireline pretest tool (PressureXpress) with dynamic pretest control was deployed successfully. This study further integrates pressure data from multiple sources - Production Logging (PL), Static Bottom-Hole Pressure (SBHP) and Formation Tester (FT) to enhance reservoir understanding. The integrated dataset supports WRM decisions and field development planning by enabling accurate depletion mapping, compartmentalization analysis, and improved well placement strategies in complex HPHT environments. In tight, complex reservoirs such as North Kuwait's Middle Marrat formation, acquiring reliable zonal contribution data using multirate production logging (PLT) is highly challenging due to low flow rates and crossflow effects. Reliable PLT data is therefore difficult to obtain, making pressure measurements in open hole essential for evaluating reservoir behavior. This paper also demonstrates that a formation tester rated for 8,000 psi differential pressure was operated near its upper design limits without operational anomalies. Multiple pressure points were acquired across the reservoir, revealing distinct pressure regimes and significant depletion in certain intervals. Successfully acquired formation pressures highlighted current zonal pressures ranging from ~3,000 to 11,000 psi, caused by the tight limestone matrix and anhydrite acting as vertical flow barriers. Interval Pressure Transient Testing (IPTT) performed on the buildup data enabled estimation of permeability across zones. Reservoir pressure and permeability profiling played a critical role in bridging the gap between static and dynamic in-place volumes, identifying development targets, optimizing zonal coverage, and supporting effective field development planning in these tight HPHT carbonate reservoirs. This paper contributes novel insights by demonstrating how accurate formation pressure measurements are not only critical for dynamic reservoir characterization but also instrumental in planning advanced operational strategies such as Coiled Tubing Drilling (CTD) and stimulation. The integration of pressure data into WRM workflows further enhances development planning by identifying unlocked reservoir potential. As a result, this work not only reinforces the value of pressure data but also adds a practical framework for its application in improving field development efficiency in complex reservoirs.