Intelligent instrumented fields or i-fields hold promise to be the next game changer technology in the Exploration & Production industry. The instrumented oilfield consists of a network of sensors permanently installed in wells and on the surface or on the seabed. The network will continuously monitor a range of parameters, including temperature, pressure, acoustics and fluid flow. Changes in reservoir dynamic properties that occur during production and injection are recorded by the sensors in real time. Real time monitoring of flood fronts between wells provide “an early warning system” to optimize field development strategies and longer term recovery.

Geophysical monitoring tools are based on measurements of physical properties and their contrasts over the producing life of a reservoir. Each tool responds to contrasts in a physical property like electrical resistivity, magnetic susceptibility, density and elastic modulii. In intelligent oilfields, a variety of seismic and non-seismic instruments will be permanently installed along with other instruments in the total infrastructure. The measurements will image reservoir fluid distribution during the life of a field. Some tools are proven while many others are emerging. Time lapse seismic measurements or 4D seismic is a mature technology used successfully in many fields to monitor injected fluid flood fronts, locate by-passed oil and map pressure compartmentalization. Permanently installed multicomponent seismic receiver arrays on sea floor and in boreholes are being used for acquiring 4D seismic frequent intervals. The additional shear wave data monitor in-situ stress changes, fracturing and pressure fronts. The permanent receivers can also be used for continuously recording passive seismic data. In passive mode the sensors will detect triggered microseismic events emanated from minute slippages in reservoir rocks due to injection and production activities. Recorded events could map the flood front movement and preferential flow paths at interwell scale. Electromagnetic or EM methods, on the other hand, rely on changes in electrical properties due to reservoir saturation changes as hydrocarbons are produced and water injected. Surface deformation caused due to pore pressure changes in reservoirs with production and injection activities can be continuously monitored using satellite radar interferometry (InSAR), ground-based GPS, and surface tilt meters.

This lecture will discuss the various proven and emerging geophysical tools that demonstrate promise in detecting and mapping of reservoir flood front movement during the life cycle of a producing field. Geophysical methods could be incorporated in the suite of instrumentation deployed in the intelligent fields of the future. Permanently installed geophysical instruments in the i-fields could bring a new paradigm in real time field wide reservoir fluid monitoring.