High Resolution Reservoir Characterization While Drilling: First Case Study from the Middle East Carbonates with Innovative Multi-Measurement Borehole Imager for Non-Conductive Mud
التفاصيل البيبلوغرافية
العنوان:
High Resolution Reservoir Characterization While Drilling: First Case Study from the Middle East Carbonates with Innovative Multi-Measurement Borehole Imager for Non-Conductive Mud
The Middle East Carbonates have been prolific hydrocarbon reservoir, producing through different units of Cretaceous, Jurassic and Permian over decades. However; inherent heterogeneity, karstification and fracturation in various facies often spring surprises in development wells; and many wells drilled with Oil-base mud (OBM) could not image these features with logging while drilling (LWD) technology for characterization and model updating since e-line logging is usually discouraged in such wells. This work presents the first ever case study from the Middle East Carbonates where an innovative new technology LWD borehole imager for OBM was deployed to understand the subtle geological variations that control the fluid flow. The multi-measurement borehole imaging technology was deployed while drilling with OBM to acquire apparent resistivity and ultrasonic images simultaneously to image the subtle geological features that often control the reservoir properties but didn’t get characterized earlier due to technology limitations. Around 13,000ft of lateral was logged while drilling through Cretaceous carbonates, traversing through different layers going up and down in stratigraphy; showcasing subtle variations with complementing images that helped understand the vug distribution, bioturbation, faults and dissolution seams in addition to the bedding boundaries.Vugs tend to control the fluid flow rates in many facies, and vug density curves derived from the images helped in characterizing the key-intervals. Qualitative trends are validated with mobility estimated from independent LWD measurement, providing much-needed confidence in the new technology imaging. Also, the correspondence of image facies to the fluid facies derived with surface logging while drilling confirmed the subtlety observed in the geological variations through the lateral. This first-ever case study provides plethora of new information for model updating that was hitherto unavailable for some reservoirs where development wells were drilled with OBM, and existing imaging technology of gamma ray, photoelectric factor and density were not able to decipher any of such features that are imaged now while drilling with multi-measurement technology.
