Automatic Microseismic
Reverse Time Imaging
Ashley Fish⇤ and Paul Sava
Center for Wave Phenomena
Colorado School of Mines
X
Well A
WellB
Geophones
Z
Stimulation Well
X
Well A
WellB
Geophones
Z
Stimulation Well
wellA
Data courtesy of Cimarex Energy
wellB
wellA
wellB
Imaging strategies
Pick: on the data
Propagate: by ray tracing
Propagate: by modeling
Pick: on the wavefield
clean
noisy
dt (s)
xt
dz (kft)
xz
zt
dx (kft)
dt (s)
clean
noisy
Imaging by time reversal
Imaging principle:
Events exist where wavefields focus
Imaging by time reversal
Imaging principle:
Events exist where wavefields focus
Spatial focusing:
Temporal focusing:
W (x, y , z, t = tperf )
W (x = xperf , y , z, t)
Challenges
Acquisiton aperture - limited
Time reference - unknown
Velocity model - innacurate
Limited aperture
Incorrect time
Incorrect velocity
Limited aperture
wellA
wellB
✏
Single array - well B
synthetic
field
Single array - well A
synthetic
field
Dual array
synthetic
field
Incorrect time
synthetic
field
Incorrect velocity
Incorrect velocity
Future work
Research questions
Sufficient acquisition aperture?
Correct slowness assumption?
Update velocity model?
Acknowledgement
Cimarex Energy