Mapping subsurface flow paths: Connecting reservoir data with passive and reflection seismic imaging
High-resolution reflection seismic data can reveal fracture domains, corridors, and property variations that correlate with fractures. Volumetric structural attributes reveal subtle fracture and fault patterns. Seismic attributes such as velocity anisotropy and mechanical properties can help define fracture domains. Similarly, high resolution seismic data reveals subtle structures that define fracture domains. Correlating seismic attributes with structural interpretations increases confidence in both sets of results. Are these features the reservoir plumbing system? Reflection data cannot image reservoir permeability, natural or induced fracture transmissivity, or the connectivity of such features. A road map does not show the traffic. Conversely, microseismic methods can illuminate induced and natural fracture fluid flow paths – but microseismic methods primarily illuminate features connected to a treatment well, not all transmissive features. Conventional microseismic methods show only hypocenters, the highest energy microseismic events, which typically occur in the near-wellbore region and around fault zones . This talk will also discuss Tomographic Fracture Imaging™ (TFI™) – a new, patented microseismic technology that is capable of mapping large areas with uniform coverage and extremely high sensitivity. TFI can be used during fracture treatments or in a purely passive mode, for example during continuous recording of 3D reflection surveys. TFI directly images seismically active fractures as complex surfaces in space, not dots-in-a-box, and can track movement of the frac fluid pressure wave through time. TFI can also be used for quiet-time monitoring as an add-on to conventional 3D reflection surveys, and for injection and production monitoring. Integrating TFI with conventional microseismic results, 3D seismic attributes, kinematic structural interpretations, natural fracture data from image logs or core, and reservoir data including interference tests and chemical tracer results reveals which potential flow paths imaged by reflection seismic methods are transmissive during fracture treatments, or are seismically active during purely passive monitoring.
AAPG Search and Discovery Article #90156©2012 AAPG Rocky Mountain Section Meeting, Grand Junction, Colorado, 9-12 September 2012