Abstract The South Kuwait Deep Jurassic formation is classified as an unconventional with abnormal pressure, low matrix permeability, and porosity. This heterogeneous carbonate formation yields light oil but has a significant issue with asphaltene deposition in the wellbore. During the initial field development phase, the field began to suffer from a significant production decline and rapid reservoir pressure depletion. These challenges led to the stimulation of the wells, driven by multiple factors, the desire to connect natural fractures, fully drain the formation, and increase the Estimated Ultimate Recovery (EUR) of the wells by accessing additional stimulated reservoir volume. Following well candidate selection, developing a solution phase that would achieve the treatment’s objectives while addressing reservoir challenges such as asphaltene flocculation, stimulation under depleted conditions, and high fluid leak-off tendency became one of the primary concerns. Upon identification of organic deposits, cost-effective remediation strategies were implemented, including the injection of unique Aromatic-Aliphatic Blends (AAB) to re-dissolve deposited asphaltenes near the wellbore and increase injectivity for stimulation. The wells were then treated using High Viscosity Friction Reducer (HVFR) PAD fluid and a modified single-phase retarded acid system (mSPRAS) to ensure deep and branched ramifications. The chemical diversion system was designed with hydrochloric acid and viscoelastic surfactants to enhance penetration and divert fluid from high-permeability zones into low-permeability zones. Holistic design diagnostics—including memory gauge data, Diagnostic Fracture Injection Test (DFIT) analysis, and swift log analysis for fracture height computation—were conducted to revalidate fracture simulations and fine-tune the design, rather than relying on conventional "cookie-cutter" methods. The treatment design focused on improving fluid loss control while initiating high-conductivity fractures within the reservoir. Strategic measures, including the use of optimized diverters and tailored acid systems, were implemented to maximize fracture length and effectiveness. Based on comparative evaluation, employing these strategies has resulted in significantly improved performance compared to wells fractured conventionally. Bottom-hole data, fracture analysis, and log data confirmed that the fracture remained within the targeted interval, with an average half-length of 300 ft. In fact, the productivity index of the wells increased significantly, representing a substantial enhancement in output. Furthermore, the treatment effectively mitigated risks associated with asphaltene deposition. This paper summarizes the candidate selection criteria, application of this unique stimulation design in Kuwait, operational procedures, diagnostic tools, well clean-up, and the production performance aspects of the treatment. The success of this technique is critical for overcoming production decline and reservoir pressure depletion and for effectively stimulating this prolific unconventional carbonate formation. The insights presented can be applied to similar challenges in other fields.
AlAsfour et al. (Mon,) studied this question.