Technical Luncheons
4D Seismic in the Deepwater – Challenges and Rewards
Speakers:
David Johnston, ExxonMobil
(AAPG Distinguished Lecture)
Date/Time: Thursday, April 10, 2008 - 11:30 am
Location: Telus
Convention Centre - Calgary, Alberta
The cut-off date for ticket sales is 1:00 pm, Monday, April 7, 2008*
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ABSTRACT
Time-lapse or 4-D seismic data has proven value in reservoir management, increasing reserves and recovery by locating bypassed and undrained hydrocarbons and optimizing infill well locations and flood patterns. 4-D seismic can also decrease operating costs by reducing uncertainty in the reservoir geologic model and flow simulation, optimizing completions, and minimizing the number of dry holes. 4-D is simply the use of multiple seismic surveys shot over a producing field. Changes in the seismic response typically occur because of production-induced changes in saturation and pressure. Successful 4-D projects have been carried out in a wide range of geographical areas, geological settings, and depletion scenarios.
To maximize the value of a 4-D seismic project, planning for 4-D is a critical part of an overall field lifecycle strategy. In exploration, assets can be screened for potential 4-D application. Early in development planning, 4-D seismic models based on reservoir flow simulations and geologic models are used to estimate the magnitude and interpretability of the 4-D response, evaluate optimal survey repeat times, and assess potential business impact. Once the field is under production, effective 4-D project execution requires collaboration among asset team geoscientists, engineers, and field operations with geophysical acquisition and processing specialists.
Fields in West Africa and the Gulf of Mexico demonstrate that the deepwater production environment presents unique opportunities and challenges for 4-D projects. Issues range from the impact of surface facilities on data quality to contending with ongoing field operations. In addition, aggressive drilling schedules dictate a rapid turnaround of 4-D data. But these fields have high drilling and well intervention costs and 4-D seismic may be the only available field-wide reservoir surveillance tool. This presentation shows how 4-D seismic technology can be used in deepwater reservoir management and discusses some of the challenges faced in its application.
BIOGRAPHY
David Johnston graduated in 1973 with his B.Sc. in Earth Science from Massachusetts Institute of Technology. He then went on to receive his Ph.D. in Earth Sciences from Massachusetts Institute of Technology in 1978. Between 1978 and 1979 Johnston did doctorial research at the Massachusetts Institute of Technology. From 1979-2000 Johnston worked as a Research Geophysicist for Exxon Production Research Company. From 2000 to 2002 he worked as a Research Geophysicist for ExxonMobil Upstream Production Research Company.
Presently Johnston is a Senior Geophysical Advisor for ExxonMobil Exploration Company. Johnston has authored and co-authored over 25 external publications, numerous publications internal to ExxonMobil, and presented over 50 technical papers at conferences including AAPG, SEG, SPE, and OTC. Johnston is involved with AAPG, Society of Exploration Geophysicists, Society of Petroleum Engineers, and American Geophysical Union.
