Reviving the Jurassic: An Integrated Evaluation and Stimulation Strategy for Complex Carbonate Reservoirs in North Kuwait Gas Field

Abstract The North Kuwait Jurassic carbonate HPHT gas reservoirs present a dual challenge of low matrix permeability and significant pressure depletion, complicating production efforts. Severe depletion renders these reservoirs highly susceptible to near-wellbore damage from drilling fluids and solids, which often creates a barrier that conventional acid stimulation cannot penetrate due to rapid reaction rates at high temperatures. This paper details an integrated workflow developed to overcome these limitations, utilizing advanced diagnostics and a novel mechanical-chemical stimulation approach. The methodology employs Pulsed Neutron Multifunction Spectroscopy (PNMS) and Far Field Acoustic Imaging (FFAI) to quantify formation damage and identify solid impediments such as Barite and cement fines within fracture corridors. To restore injectivity, a Post Perforation Dynamic Underbalance Explosive Clean-up (PPDUBEC) strategy was implemented, utilizing optimized gun carrier lengths and wellbore pressure offloading to maximize debris removal. This was followed by a stimulation treatment using a Lightweight Single-Phase Retarded Acid (SPRA) system with nitrogen foaming to achieve deep matrix penetration. Case studies of three Middle Marrat wells (Well-A, Well-B, and Well-C) demonstrate the efficacy of this workflow. Quantitative validation via PNMS logs revealed a greater than 50% reduction in near-wellbore solids and significant porosity increases—up to 400% modeled efficiency in Well-C—confirming successful tunnel cleaning and connection to the natural fracture network. The integrated approach successfully unlocked commercial gas deliverability in tight, depleted reservoirs where previous methods had failed. Post stimulation stabilized production reached the level up to 3.0 folds of increase compared to nearby wells stimulated without the Post Perforation Dynamic Underbalance Explosive Clean-up (PPDUBEC) approach.