| Several technologies are advancing to better monitor and optimize reservoir production. These include time-lapse surface and borehole seismic, shear wave technology, directional drilling, permanent downhole sensors, intelligent well completions, fiber optics, remote control operations, data management and Internet technology, shared earth models to extract and archive reservoir knowledge, data visualization, parallel computing, and rapid modeling, processing, analysis and decision-making tools. These diverse technologies are converging toward the target of real-time monitoring and optimization of reservoir production: The instrumented oilfield. In the geophysical world, time-lapse seismic technology has been rapidly advancing over the past few years. Several industry case studies have been presented that show the capacity of 4D seismic to monitor injected fluid fronts, locate bypassed oil, map pressure compartmentalization, and delineate the sealing or leaking flow properties of faults. High resolution time-lapse seismic monitoring has been performed in the borehole, in VSP and crosswell geometries. Together, time-lapse surface and borehole seismic techniques have the possibility to cover multiple reservoir scales in terms of both spatial and time-lapse resolution. Permanent installation of receiver arrays, originally motivated by increased repeatability and signal-to-noise energy, have the potential to offer useful benefits in data acquisition cost reduction and real-time surveying flexibility. Since multicomponent receivers can be installed for nearly the same price as acoustic sensors, the additional information from shear waves can be useful for monitoring pressure fronts, in situ stress, and real-time fracturing. However, many hardware, software, and logistical issues remain before permanent seismic arrays become a practical reality. In the engineering world, downhole instrumentation and borehole technology have been experiencing rapid development. Downhole sensors are available to measure reservoir state variables such as pressure, temperature and saturation. These sensors can be permanently installed and can feed continuous data by fiber optics to remote control operation centers at the surface. Directional drilling can be aided in real-time by logging-while-drilling (LWD) measurements and seismic drill-bit steering. Smart wells with multiple-level intelligent completions can drain multiple oil reservoirs in an optimal manner by measuring flow rates and pressure during production, and reconfiguring the completion specs on the fly to maximize recovery. More field pilot tests are needed to advance the technology. On the combined geoscience and engineering analysis front, these complex and real-time monitoring systems will produce a huge volume of data that requires intelligent processing to extract reservoir knowledge and value. How will the flow of data be transmitted, and what portion will be storable? How will the information content—the reservoir knowledge—be extracted from the data stream and archived in a continuously evolving and updated reservoir model? The solutions to these challenges hinge on evolving technologies in data management, information technology, high-speed networks, Internet communications, rapid data visualization, parallel computing, the shared earth model concept, and integrated modeling, processing, analysis and decision-making tools. Much research remains to be done; we need to get out there, put these systems in the ground, test them, and learn as we go. |
