Estimation 1D Geomechanical Model by IPv3.5.pdf

Using IP to build GM

1. Petroleum Geomechanics
Chapter 12: Case Study for Estimation of
1D GeomechanicalModel by IP V3.5 and
Applying for Wellbore Stability Analysis
Ta Quoc Dung, PhD
Tran Trung Dung, PhD
Nguyen Van Thuan, MSc
Geomechanicsconsultant.
Contact:
E: [email protected]
T: [phone]

2. Data input

3. Data input
•GR (Shale Volume)
•Density
•DTC, DTS (velocity)
•Resistivity
•Core (mechanical test)
•LOT/FIT
•MDT
•Well top
•Well survey.

4. Data QC and Preparation
•DTC_velwas derived from Velocity of Seismic
•DTC_vel= 304800/Vel

5. Data QC and Preparation
•Splice the curves of DTC_veland DTC (from wireline).
•Right-click on track 2 to make 2 zones for each curves.
•Click on DTC_velcurves in zone 1 in track 2, and click on DTC
curves on zone 2 in track 2.
•Click and keep the line between two zone to up or down for
fitting the DTC_fullcurves.

6. Equation of DTS vs DTC
•DTS = 0.6970*DTC^1.2116

7. DTS or Vp
•Splice DTS_fullas way of DTC_full

8. Density Estimation
•Calculate the gap
density by using
Gardner equation.
•RhoGrad=
0.24*DTC_full^0.25
•Splice 2 curves
density as splice
DTC_fullcurves.

9. Overburden Stress (Sv)
•Advanced Interpretation ->Pore Pressure
Calculation ->Overburden Gradient Calculation

10. Rock Properties
•Estimate Poisson Ratio, Bulk
Modulus, Shear Modulus.

11. Rock Properties
6.894*(0.018*(e_dyn/6.894)^2+0.422*e_dyn/6.894)2*density*(1+pr)*vs^2/10000000
•Estimate Young’s Modulus
(Dynamic and Static)

12. Rock Properties
•Internal Friction Coefficient
0.9*tan((18.532*(Vp/1000)^0.5148))
tan(asin((Vp-1000)/(Vp+1000)))
•For Sandstone
•Shale Volume
cut-off: 0.7
•For Shale

13. Rock Properties
•Rock Strength (UCS)
•For Sandstone
•For Shale
•Shale Volume
cut-off: 0.7
185165*exp(-0.041*DTC_full)
2.12e9*(dtc_full)^-2.93

14. Rock Properties

15. Rock Properties
•Calculated data
is well fitted
with core.

16. Pore Pressure (Pp)

17. Pore Pressure (Pp)
•Using the NCT
to edit the
trend of Pp
calculated by
Sonic and
Resistivity

18. Pore Pressure (Pp)
•Then, based
on the
measured
points (MDT)
and offset well
located nearby
region, Pp
trend was
created.

19. Pore Pressure (Pp)
•Adjust the
NCT and
reduce noise
to fit MDT
data.

20. Fracture Gradient (FG)
•FG_EatonEquation:
FG_Eaton= (poisratio/(1-poisratio)*(obgrad-test:ppg_son))+test:ppg_sonmin
()
1
h vp p
v
SSPP
v


Minimum Horizontal Stress (Shmin) or
FG was estimated by following
equation related to Pore Pressure (Pp),
Overburden Stress (Sv) and Poisson
Ratio:

21. Fracture Gradient (FG)

22. This case study located in Normal Faulting Regime.
The magnitude of S
Hmaxat depths without modelling is determined
using an effective stress ratio approach:
S
HmaxProfile 
 
max
max min
min
H
Hh
S
vh
SS
ESR
SS



ESR
S
Hmax
= Effective Stress Ratio for calculating S
Hmax
S
v = Overburden Stress
S
hmin = Minimum Horizontal Stress
Based on the previous study in similar
location, in this case study also was
used the ESR = 0.5to estimate S
Hmax

23. 1D GeomechanicalModel
LOT
FIT
MDT
ECD
The
calculated
results best
fit with
measured
points.

24. 1D GeomechanicalModel
LOT
FIT
MDT
ECD
The
calculated
results best
fit with
measured
points.

25. Output Data for Wellcheck
Stick on box to make the excel format
TVD for matching with rock file

26. Wellbore stability analysis by Wellcheck

27. Collapse Pressure: In-house softwaresvs Excel