Operators and service companies have to constantly re-evaluate their understanding of the sub-surface, the technology and methodology of accessing the reservoirs, and the ways and means of extending the production plateau for as long as possible. As has been stated by others, the only constant in the continued search for hydrocarbons is change. This requires an open mind as to the technology employed during reservoir characterization and wellbore construction, but should also entail a critical review of the collaboration efforts between operators and service companies.
The paper illustrates the benefits of an integrated team approach to Reservoir Navigation, based on the critical review of several multi-lateral wells drilled recently to successfully access the thin reservoir layers offshore Dubai. Combining the extensive field knowledge of operator experts with the specific Logging While Drilling (LWD) tool response knowledge of service company experts allowed multi-lateral wells of over 4,000' length to be positioned accurately in challenging reservoirs of less than 6' thickness.
This paper illustrates the introduction of several techniques for navigating and characterizing challenging hydrocarbon reservoirs utilizing real-time borehole images from LWD density and Gamma Ray measurements, coupled with the more traditional deep reading resistivity measurements. Incorporating structural geological information derived from the imaging tools into real-time reservoir modeling provided crucial information that allowed the use of traditional resistivity data for wellbore placement in spite of the low resistivity contrast between the reservoir and the surrounding formations. Wellbore tortuosity was minimized using the latest generation rotary closed loop steerable system (RCLS), ensuring completion operations proceeded without any problems.
Integrating the expertise of both operator and service company experts by providing a central data review and collaboration center enabled the true value of the data to be realized. Real time data review and interpretation provided the basis for informed real-time decisions, positively impacting well placement and reservoir contact as well as reducing Non Productive Time.
The paper summarizes best practices and learning points regarding the cost-effective application of LWD and RCLS to gain access to challenging reservoirs.