|
|
|
|
Fracture Analysis and Microseismic |
|
|
|
Production from fractured reservoirs
requires an indepth knowledge of fracture patterns,
networks, and orientations. VSP assists this process by
providing fracture information at a seismic scale, which
usually complements local petrophysical information, such as
image log and core analysis, and regional information based
on surface seismic information obtained using techniques
such as CGGVeritas’s FracVista™ system.
Fracture Delineation
Analysis of shear-wave data yields information about the
fracture azimuth. Shear waves split into a fast and slow
mode with directions of propagation parallel and
perpendicular to fractures respectively. |
Baker Atlas’ multilevel tools have
thesensitivity to receive high frequency
microseismic energy. |
|
To
analyze shear-wave data, VSFusion uses a proprietary wavemode
separation technique to perform amplitude analysis on 3D
rotated data. Hodogram displays and amplitude ratio charts
reveal the orientation of fractures hidden in the seismic
data. |
|
Fracture Mapping
Mapping of fractures provides information on the orientation
and 3D location of fractures in the reservoir. This
information is crucial for well planning in
compartmentalized reservoirs and can be applied to enhance
production in all
fractured reservoirs. We first analyze natural seismic
activity in the reservoir generated along dynamic fractures
using techniques developed by earth seismologists.
Injection, production, and other fluid movements enhance
the microseismic activity. Micro-epicenters fractures and
seismic lineations are accurately mapped in much the same
way as the Earth’s tectonic plate boundaries have been
mapped using earthquake seismology.Highly sensitive Baker Atlas
receivers are placed in the well for a period long enough to
receive seismic energy from numerous microseismic events. If
the reservoir exhibits significant microseismic activity, it
is worth considering deployment of permanent sensors to
monitor the field throughout its life to reveal valuable
information about injection efficiency, production decline,
and fluid front movements.
|
A North Sea example of fracture mapping. Each red dot is a
microseismic epicenter revealing fracture patterns in the
reservoir. |
|
 |
|
|
