Seismic Reservoir Monitoring : Market, Technology and Players
Authors: Christie Philip A.F. 
Published: October 2008

Abstract
Seismic Reservoir Monitoring denotes the interpretation of successive 3D seismic volumes acquired over a producing reservoir to provide information on production-induced changes in the reservoir. The concept is not new but hitherto there have been few documented examples of its successful application and even fewer statements of economic value. Several recent case studies have demonstrated the technical viability of time-lapse seismic to image reservoir changes and drive decisions on reservoir development. New technology for reservoir monitoring is emerging from the collective efforts of oil companies, institutes for research and development, and contractors. While a driver for this technology is the perceived need to image hydrocarbons and their movements in the subsurface, the business challenges are as important as the technical challenges. Seismic Reservoir Monitoring may be demonstrated, but further development remains to convert this technical progress into a business reality. This paper explores some of the challenges from a contractor's viewpoint, reviews the business opportunity in the context of recent experience in the industry and offers some thoughts on how oil company and contractor may reach a win-win situation.

Introduction
Time-lapse measurements - of which successive 3D seismic surveys ("4D seismic") is the principal technology, supported by time-lapse borehole seismic and repeat well-log measurements - can indeed image production-related changes in the sub-surface away from the well. The ability of 4D seismic to image reservoir changes varies with the type of reservoir rock and the fluids filling the pore space. In general terms, less consolidated clastic reservoirs with good porosity and light hydrocarbons are the most amenable to time-lapse seismic. Depending upon the nature of the reservoir setting, the time-lapse signal may be due to fluid movements, fluid phase changes, pore pressure changes, temperature effects or the propagation of stress changes into geomechanical elements within and beyond the reservoir. The separation of these effects pose some of the future technical challenges to researchers, but studies presented at the SEG Development and Production Forum in Kananaskis - and at the 69th SEG Annual International Meeting in Houston - demonstrated the existence of a production-related, time-lapse signal (Refs. 1-3). Some case studies also quantified the projected economic benefits from reservoir management decisions based on timelapse surveys interpreted with reservoir simulations (Ref. 4). We might ask ourselves whether, after several years of experimentation, we are at the threshold of a 4D business. How might the economic climate affect the emergence of this promising technology ? I review some of the ideas discussed at Kananaskis, offer some personal opinions on the way that the technology and the market may develop, especially in the current business climate, and close on a contractor's dream for the future - which in large part may already be upon us.

4D Technology Development
Like other contractors, Schlumberger has focused on new technology to support its range of products and services.