Advanced Geological Characterization of Karst Morphologies Utilizing Integrated Drilling and 3D Seismic In Production Optimization Strategies

Summary Results from the latest infill drilling campaign in Qatar’s largest offshore oil field revealed a unique network of incisions and karstification. Utilization of 3D seismic attribute analysis at both planning and drilling stage using Spectral Decomposition allowed detail mapping of the incision channel network including the estimated thickness and dimensions. Additionally, the application of advanced ultra deep azimuthal resistivity tool (GeoSphere) was pivotal in accurately identifying and mapping the incisions, dolines, and fissures. The characterization of the incisions allowed precise implementation of the multizone completion strategy. The ability to estimate the properties (and possible flow potential) of the incisions allowed accurate isolation of the selected incisions deemed high risk of non-conformance in the event of accidental penetration. Additionally, the complexity of the facies variability and diagenetic imprint was accurately captured through the integrated geological characterization. Since each facies carries a different PI, the integrated characterization played a critical role to accurately differentiate each facies. Separating the different facies using multizone smart completion has proven to be very successful in production optimization and reservoir management in numerous horizontal wells, as proven by the quarterly and half yearly zonal tests.