Abstract
This paper demonstrates how new Logging While Drilling (LWD) and Measurement While Drilling (MWD) tools were used to optimise placement of 3 sub-horizontal wells in a faulted, sand-shale oil bearing Brent Group reservoir known as the Otter Field, Northern North Sea, United Kingdom. As the target reservoir layer is only 8m thick and sub-seismic faulting and subtle changes in dip occur in the field, geosteering of the well paths was anticipated prior to commencing drilling. To aid with geological steering of the wells a new LWD tool was run: the azimuthal GR-resistivity device and this provided high-resolution borehole images of formation geology (eg. formation layering and dip, fault location and orientation). Using state-of-the-art mud-pulse MWD telemetry and the world-wide web, the images and other LWD data (eg. porosity) were made available, real-time, to both the onshore and offshore drilling team. Detailed geological cross sections constructed in real-time from the image logs aided steering the wells to the optimum geological locations. One of the three production wells [well 210/15a-T2 (P1)] is used to demonstrate how the imaging while drilling, viewed real-time via the web, was applied. This case study highlights the benefits the technology brought to the drilling operation and field development in terms of efficiency improvements in geological analysis and well steering decision making and maximized oil production through optimum well placement.
