As projects grow in complexity, interface management becomes more important and difficult. In February, a group of 120 reservoir and topsides professionals met in San Antonio, Texas, for SPE’s “Bridging the Gap Between Reservoir Engineering and Facilities Design” workshop to discuss the topsides/reservoir interface.
The eight-session workshop addressed a variety of projects and challenges, ranging from community issues in shale gas developments to new methods of reservoir surveillance and integrated modeling.
The reservoir requirements session included identification of reservoir issues, lessons learned in accounting for reservoir uncertainty in the design of surface facilities for a heavy oil waterflood development on the North Slope of Alaska, and a comprehensive overview of environmental issues involved in the development of surface facilities for unconventional reservoirs.
Facility requirements for offshore facilities, including major deepwater developments, and for the design of onshore, midstream facilities were covered in another session.
Effective reservoir fluid sampling and characterization and its importance in subsurface modeling and topsides design were highlighted. Speakers presented state-of-the-art sampling technologies and identified common sampling errors. Topsides engineers learned that reservoir fluids are not well mixed as in a stirred tank. Instead, engineers need to be mindful that composition/concentration gradients exist in reservoir fluids, and fluid composition changes over time.
In the discussions of approaches to managing the reservoir/topsides interface, a reoccurring topic was reservoir uncertainty. Reservoir data are inherently uncertain because of factors that cannot be accurately measured or controlled (e.g., pressure, permeability, water saturation, etc.). Conversely, topsides designs tend to be point designs (designed for a particular operating rate) with much less consideration given to the uncertainties in operating conditions and production rates.
One of the sessions was dedicated to common reservoir uncertainties. Speakers addressed means of early identification of uncertainty in project planning, the novel use of decision trees to better quantify uncertainties, and the integration of uncertainties into the flow assurance strategy.
Presentations on reservoir surveillance and integrated modeling included case studies demonstrating the integration of reservoir surveillance and facility design/operation to maximize production from a mature field. A newly developed integrated modeling method and work processes to maximize benefits from the modeling were also discussed.
While much of the workshop’s content dealt with planning and design, a session focused on integrity management over the entire life cycle of the facility. The changing reservoir fluid compositions mentioned above are also the drivers of changing integrity issues—and their management—over the life cycle of the project.
A speaker representing a major operator presented the company’s approach to early decision framing and decision analysis. Another shared an operator’s optimization of drilling center locations in the consideration of a facility design.
While engineers are typically most comfortable discussing technical issues, no interface workshop would be complete without a nod to social issues. The final session included discussions of cognitive and psychological bases for interface problems; the need for sharing of reservoir uncertainty with topside design personnel; and a look at the future of the oil field with suggestions for development of more flexible designs to account for the reservoir uncertainties that change over time.