Turbidite reservoir compartmentalization and well targeting with 4D seismic and production data: Schiehallion Field, UK

Abstract

This paper discusses integration of production surveillance techniques, focusing on the use of 4D seismic data to identify reservoir compartmentalization. We present two examples of recently drilled compartments that were successfully identified following integration of surveillance data with detailed reservoir modelling work. Our examples are from the faulted, Paleocene channelized turbidite reservoirs of the Schiehallion oil field, offshore West of Shetlands, U.K. The first example provides a good case history of a 4D Integrated Reservoir Modelling (4D IRM) approach -which involved integration of dynamic well data with 4D seismic, and iterative revision of geological and reservoir simulation models. Two newly identified targets were drilled and completed successfully using these techniques. The second example illustrates a situation where 4D seismic interpretation was key in identifying a new infill target.Production in the Schiehallion Field started in 1998, and the current development scheme totals 46 wells (22 producers and 24 water injectors). During the early years of production it became apparent that geological connectivity, fluid flow and pressure communication between wells was not as inter-connected as expected. As a result the number of wells required to maximize the recovery has more than doubled to that specified in the original development plan, and the number is expected to increase further as the field matures. Continuous collection of bottom hole pressure data from permanently installed gauges, well testing and production logging (PLT) supported by a regular time-lapse (4D) seismic programme are used to update conceptual thinking and thus constrain geological and flow simulation modelling. This data integration results in improved understanding of the static and dynamic reservoir compartmentalization and well connectivity.

The geological risks of exploring for a CO2 storage reservoir

“…Some Paleogene oilfields in UK water have a complex architecture, formed by turbidite channels, sheet turbidite sandstones and sealing faults . Examples include the Schiehallion Field and Pierce Field (Gainski et al, 2010;Scott et al, 2010). In the Southern North Sea, it has been reported that the Triassic Bunter Sandstone aquifer is more suitable for CO2 storage reservoir than the Permian Rotliegend Sandstone because it has less compartmentalization problems (Holloway et al, 2006).…”

Evaluation of reservoir compartmentalization and property trends using static modelling and sequence stratigraphy

“…This leaves the middle and western regions devoid of well control. The area coloured yellow represent volume of gas not tested by any well often realized through experience relatively late in production life of reservoirs (Gainski et al 2010). Successful field appraisal and production optimization can be achieved through accurate characterization and prediction of reservoir compartmentalization and its effects on fluid flow (Barkved et al 2003).…”

Stochastic simulation of channelized sedimentary bodies using a constrained L-system

“…These bodies are composed of heterogeneous deposits that can contain fluids or act as flow barriers. Such barriers may compartmentalize the reservoir and make its exploitation harder, especially when combined with sealing faults [e.g., Gainski et al, 2010]. Channel modeling can help to study and anticipate more precisely the flow behavior.…”