Abstract
The industry today is challenged to maximize recovery from existing assets, meaning that increasingly complex and thin reservoirs must be drilled and evaluated. Consequently, reservoir management efforts aimed at maximizing production through optimal wellbore placement require increasingly sophisticated geosteering and formation evaluation capabilities.
This paper discusses the use of a newly deployed azimuthal, deep-reading, resistivity tool for geosteering and formation evaluation while drilling in the Oseberg Field. This tool, combined with well steering software, gave geosteering engineers the ability to steer the well not only on variations in resistivity but on direct measurements of resistivity that delineated layer boundaries and provided early warning of approaching bed boundaries. This system created a complete picture of the layers above, below, and around the sensor. A complete picture improved our understanding of the reservoir's geology and aided us in placing the well in thin sand. It also improved the capability to steer the well through the most productive part of the reservoir while maintaining a desired distance from adjacent formations.
In addition to geosteering and well placement, advanced application algorithms developed for this tool are used to calculate formation resistivity and formation anisotropy, as well as dip and azimuth of formations within and around the reservoir.
This paper describes the planning and execution of the geosteering job done with this new technology. A flowchart of the geosteering workflow is discussed. Formation evaluation and well placement techniques based on this new azimuthal deepreading technology are explained and detailed. Lessons learned, pitfalls to avoid, and best practices and challenges are described in detail. Finally, field examples are included that show the usefulness of this new technology during steering and evaluating the Oseberg field.
