Time‐lapse seismic reservoir monitoring

David E. Lumley
2001 Geophysics  
Time-lapse seismic reservoir monitoring has advanced rapidly over the past decade. There are currently about 75 active projects worldwide, and more than 100 cumulative projects in the past decade or so. The present total annual expenditures on 4-D seismic projects are on the order of $50-100 million US. This currently represents a much smaller market than 3-D seismic, but the use of 4-D seismic has grown exponentially over the past decade and is expected to continue to do so. The major
more » ... ty provided by 4-D seismic data is its ability to image fluid flow in the volumetric region not sampled by wells. Fluid flow is thus directly imaged by 4-D seismic data, rather than solely predicted by flow simulation. In contrast to 3-D seismic, which is an exploration and development tool, 4-D seismic is quickly becoming a vital engineering reservoir management tool. Time-lapse seismic images can identify bypassed oil to be targeted for infill drilling, and add major reserves to production to extend a field's economic life. 4-D seismic can monitor the progress of costly injected fluid fronts (water, gas, steam, CO 2 , etc.) that can save hundreds of millions of dollars in optimizing injection programs. 4-D seismic can map reservoir compartmentalization and the fluid-flow properties of faults (sealing versus leaking), which can be extremely useful for optimal design of production facilities and well paths in complex reservoir flow systems. Rock physics measurements made in the mid 1980s at Stanford University predicted that thermal enhanced oil recovery (EOR) processes, especially steam injection, should be visible in repeated surface seismic surveys. The first field tests of the concept were conducted in the mid-late 1980s and early 1990s in Canada, the US, and Indonesia at several steam injection sites and one fireflood site. These early projects showed conclusively that large anomalies related to steam and heated gas were indeed strikingly visible in time-lapse seismic data. This was followed by projects to monitor isothermal gas-fluid movement, particularly by early work in the North Sea and Paris basin. These gas monitoring experiments were also successful, but it became clearer that the interaction of the reservoir rock, fluid, and gas components could enhance or degrade the time-lapse seismic signal depending on specific reservoir conditions. The past five years has seen an increased * 4th Wave Imaging Corp.,
doi:10.1190/1.1444921 fatcat:ujd6gvjj7nh75lfovfndcufubi