Time-Lapse Seismic in Reservoir Management
by Ian Jack
Duration: One to two days
Intended Audience: Intermediate
Summary: This course is intended to appeal to a wide audience (most attendees are geophysicists, but a significant number are geologists, reservoir engineers and petrophysicists). It will bring them up-to-date with the current state of the art and to enable them to make decisions involving the use of the method. It covers the rationale and driving forces behind "time-lapse seismic" by examining the current global state of reserves and trends. It examines the economics of reservoirs and their likelihood as candidates for the 4D method. It illustrates the limitations of existing methods of tracking fluid flow between wells. It will examine those reservoir properties which change with time, and what might be observed on seismic data as a function of elapsed time, together with warnings about those things which may also change which we would prefer to remain constant.
Rock and fluid physics is the link between reservoir depletion and seismic observations. Pore fluid properties and rock/fluid properties are examined in detail, together with the methodology of fluid substitution. In these sections, key success factors, key calibration requirements, and key uncertainties are addressed.
The repeatability requirements of seismic data and the use of "legacy" data sets are discussed, together with a review of the data acquisition schemes and data processing requirements for successful time-lapse analysis. The analysis and interpretation methodologies are described, as are some of the risks and a summary of experience to date. The value of the 4D technology is quantified.
A representative selection of industry case-histories covers the historical development of the method in land and marine environments right through to the current state of the technology. It includes the latest data from the permanent seismic monitoring installation at Valhal. These case histories will illustrate many of the above points and will be worked through in detail. The course finishes by noting some remaining challenges and future directions. It is up-to-date as of March 2007.