Hydraulic fracturing to determine 4 - John T. Foster · Second cycle 2050 2000 1950 1900 8 1850...
Transcript of Hydraulic fracturing to determine 4 - John T. Foster · Second cycle 2050 2000 1950 1900 8 1850...
Hydraulic fracturing to determine Hydraulic fracturing to determine S3
Hydraulic fracture initiation in vertical wellHydraulic fracture initiation in vertical well
= 3 − − 2 − ΔP − = −σminθθ
Shmin SHmax Pp σΔTT0
Leako� test (mini-frac, FIT, XLOT)Leako� test (mini-frac, FIT, XLOT)
© Cambridge University Press (Fig. 7.2, pp. 211)Zoback, Reservoir Geomechanics
from instantaneous shut-in pressure from instantaneous shut-in pressure
© Cambridge University Press (Fig. 7.3, pp. 213)
S3
Zoback, Reservoir Geomechanics
© Cambridge University Press (Fig. 7.3, pp. 213)Zoback, Reservoir Geomechanics
Step-rate testStep-rate test
© Cambridge University Press (Fig. 7.5, pp. 216)Zoback, Reservoir Geomechanics
Be careful!Be careful!
When When integrate density logs integrate density logs
© Cambridge University Press (Fig. 7.4, pp. 214)
∼S3 Sv
Zoback, Reservoir Geomechanics
What about What about ??
so
or
SHmax
ΔP = −Pb Pp
= 3 − − +SHmax Shmin Pb Pp T0
= 3 − (T = 0) −SHmax Shmin Pb Pp
Does it work?Does it work?Consider a system with compressibility βs
=βsΔVs
Vs
1
ΔP
ΔP = Δ1
βsVs
Vs
=ΔP
Δt
1
βsVs
ΔVs
Δt
Answer: Not very well.Answer: Not very well.