Advanced Time-Lapse InSAR for Reservoir Management

Surface deformation data is increasingly being used to actively manage reservoirs and optimize production. One of the techniques capable of providing a dense network of precise ground displacement data over large areas is InSAR. Recent improvements in data processing algorithms and in radar satellite characteristics have increased the quantity and quality of surface deformation measurements.

The most advanced InSAR techniques process a large number of radar images to determine displacement of naturally occurring or man-made targets. The use of multiple images allows sophisticated statistical calculations of atmospheric noise, which can then be removed from the displacement readings, increasing measurement precision to millimeter scale. SqueeSAR™, a recently released algorithm, in addition to making measurements from point targets, has introduced the capability to also extract information from spatially distributed targets, which greatly increases the density of measurement points in areas that were traditionally challenging for InSAR.

Recently launched radar satellites have lower revisiting times (i.e. the interval between subsequent radar images), which is now less than 8 days in some cases, and spatial resolution is close to 1 m2. Furthermore, the optimization of algorithms and powerful parallel processors now allow data to be processed in near-real-time.

Volumetric changes in reservoirs due to fluid extraction or injection can induce either subsidence or uplift of the ground surface. The magnitude of surface displacement depends on reservoir depth and on the reservoir/overburden characteristics. It has been shown that even reservoirs located at great depth can induce deformation of the ground surface.

Measurement of surface displacement can help understand the dynamic behavior of a reservoir and inversion techniques can lead to estimates of reservoir volume changes through time. Accurate assessments and detailed understanding of reservoir properties (e.g. the location of flow barriers or of areas of enhanced permeability) require repeated, high density measurements over large areas and with millimeter precision.

Surface deformation measurements are valuable in EOR, water flooding and SAGD activities as they can provide indirect observation of subsurface fluid movement. We show here case studies in which SqueeSAR™ data is used for the characterization of reservoirs, the delineation of active faults and for the observation of fluid flow behavior.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California