This invention provides near real-time systems and methods for acquiring
seismic data in reservoirs at very high resolution such that advancing
fluid fronts can be mapped substantially in real time. In one system, one
or more autonomous devices are deployed in the well to detect seismic
data. Each device includes at least one seismic receiver. An acoustic
energy source, preferably at the surface, induces acoustic waves into the
subsurface formations. The autonomous devices move in the well and detect
seismic waves at selected discrete locations in the well. The seismic data
is stored in on-board memory. After the data acquisition, the devices dock
at a receiver stations in the well. The receiver stations download the
stored data from the memory and transmit such data to a surface control
unit via a two-way data link between the receiver and the surface control
unit. The surface computer system also sends command signals to the
downhole receiver to control the operation of the individual devices. The
receiver stations can be programmed to control the operation of the
devices. The devices may include resident programs to perform the survey
operations at specified intervals. The data gathered by the devices is
used to update existing seismic maps in determining the boundary
conditions of the fluid fronts. For subsea wells, autonomous devices may
also be deployed at sea bottom to travel along predefined paths to collect
seismic data. A subsea control station or receiver provides power and data
transmission function for the subsea devices. The seismic data from the
well and the sea bottom are then used to update the 3D maps to obtain 4D
maps and to model the reservoirs.