High-Fidelity Real-Time Time Imaging With Electromagnetic Logging Logging-While While-Drilling Measurements
Abstract: A pixel-based based inversion approach is introduced for interpretation of deep directional resistivity logging logging-while-drilling drilling electromagnetic measurements. It can be used for real-time time reservoir mapping while drilling to accurately place the well with respect to o reservoir boundaries and fluid contacts as well as for reservoir characterization in high angle and horizontal wells. The methodology is based on the Gauss-Newton Newton approach, using an adaptive l1 l1-norm norm regularization and a robust error term to determine the 1-D D formation anisotropic resistivity profile and local formation dip. The new inversion allows high high-resolution resolution imaging of the subsurface resistivity distributions and consistent integration of measurements of different depth of investigation. To further enhance the robustness and accuracy of the subsurface images, a fast approximate 22-D D inversion is developed, which uses approximate modeling based on locally 11-D D models, resulting in reservoir images of improved accuracy and consistency in mildly 22-D and 3-D D scenarios. The inversion's ability to generate a stable robust but detailed resistivity image of the formation near the wellbore is proven on synthetic and field data.