"Time-lapse" or "4D" are names used to describe geophysical data sets that are acquired over the same area at different epochs in time (3D + the dimension of time = 4D). The general purpose is to analyse differences between data sets from different epochs, the underlying assumption being that such differences are due only to production or injection from subsurface reservoirs (subsurface saturation-change maps shown right). Differences between data sets due to other sources such as variations in acquisition/processing parameters, tides, and background noise, must be removed or equalised prior to differencing.
The Edinburgh Time Lapse Project (ETLP) is an industrially-sponsored, university-based research consortium specialising in the development and application of analysis tools for engineering-consistent quantitative interpretation of 4D seismic data. Due to its location in a Petroleum Engineering Institute, the consortium has a strong emphasis on the integration of seismic data with reservoir engineering techniques. It aims to deliver accurate estimates of those dynamic reservoir parameters that are of value in understanding the reservoir flow behaviour and connectivities, and can assist in improving field management.
One of the principal drivers in ETLP research is the data donated from sponsors. The Phase II work portfolio covered clastic and carbonate fields from the North Sea, Southern Gas Basin, Norwegian Sea, West Coast Africa, Gulf of Mexico and Oman. The next three-year phase (Phase III) of the project continues this theme, but now focussing on those datasets of high repeatability. This will allow ETLP to comprehensively examine the limits, uncertainties and insights associated with its proposed integrated engineering methodologies, and to widen their application.
For further information about this research, contact Prof. Colin MacBeth.