Using Advanced Formation Evaluation and Well Placement Techniques in Horizontal Wells to Improve Reservoir Delineation and Avoid Problem Areas
In highly produced clastic reservoirs such as the Wilmington field, well control forms the backbone of structure mapping. Conventional interpretation uses abundant vertical wells in the field to develop a structure map, which is used to identify and plan horizontal wells to access unproduced hydrocarbons. When horizontal wells are not used to update structure maps, crucial information about reservoir geometry may be missed, resulting in costly unexpected exits and water contacts that could be mitigated during planning with appropriate use of data acquired during the horizontal drilling phase of previous wells.
This paper discusses use of a newly deployed azimuthal resistivity sensor for advanced geosteering and well placement in the Wilmington field. The sensor’s geosteering capabilities in conjunction with integrated geosteering software, enabled design of an optimum well trajectory to isolate a previously produced well that exhibited water coning and to optimize well placement for maximum production. The well was steered by geosignal information that was used to map the boundary. This mapping information, from a sensor at some distance from the boundary, was incorporated into the structure map, allowing the asset team to refine the reservoir structure and confirm / discount previous interpretations. With multiple depths of investigation and an azimuthal 32 bin measurement around the borehole, the system created a complete picture around the sensor, improving understanding of reservoir structure and aiding in precise well placement for isolation and mapping.
Planning and execution of geosteering operations with this new technology in a clastic sequence of the Wilmington field is explained. Advanced well placement techniques based on this new azimuthal reading technology and software are detailed. Lessons learned, pitfalls to avoid, and best practices and challenges in this field are described in detail, with examples showing the usefulness of this new technology during the well placement planning and process.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009