Geomechanical modelling of salt diapirs, Officer Basin, South Australia
Geomechanical modelling of salt diapirs: 3D salt structure from the Officer Basin,
South Australia
D Koupriantchik1, SP Hunt2, PJ Boult3 and AG Meyers4
The presence of geological inhomogeneities, such as
salt domes, causes a significant perturbation of in situ
stress, which has potentially serious implications for
the stability of boreholes drilled in the vicinity of a salt
diapir, for the selection of exploration targets and for the
planning of exploratory drilling programs. In this study,
a salt diapir from the Officer Basin, South Australia, is
modelled numerically and the effects of the diapir on the
surrounding stress regime, rock mechanical properties
and constitutive behaviour are analysed. The results of
the computations validate previous findings. Modelling
suggests that zones of high shear stress (up to 50% higher
than far field values) are found to the northeast and
southwest of the diapir, indicating that these areas have
a higher risk of top seal breach and borehole instability.
The modelling also shows a significant area of low shear
stress to the south of the centre of the modelled salt wall.
The diapir is elongated towards the zones of higher von
Mises stress in the model, suggesting that the diapir has
grown faster in the direction of high shear stress.
(Walter et al 1995), along with the Officer, Amadeus,
Ngalia, Wiso and Georgina basins. The basin is significantly
under-explored for both hydrocarbons and minerals, with
only 7 petroleum and 42 deep stratigraphic drillholes to
date. Previous petroleum studies have detailed a variety
of findings, such as oil shows (Figures 2, 3) from four
genetically distinct families (Tingate and McKirdy 2003),
as well as good sandstone reservoirs, common evaporitic
seals and a range of potential exploration plays, including
compressive, extensional, salt-related and stratigraphic
types (Morton 1997).
The Neoproterozoic of the Officer Basin contains
extensive evidence of salt diapirism, but the outlines of the
salt bodies are not clear from the available seismic, as the
data is of poor quality. Salt bodies have been interpreted
(Boult 2005) by primarily mapping associated features,
such as collapse structures, the formation of peripheral
sedimentary sinks, and roof anticlines or domes.
The aim of this study is to predict stress anomalies around
large diapiric salt structures in the basin (Figure 4). Previously,
stress modelling has been used to predict zones of high shear
stress associated with breach of hydrocarbon seal lithologies
(Camac et al 2004) and possible hydrocarbon “pooling” (Camac
and Hunt 2004). Koupriantchik et al (2004) have shown that it
is possible to use stress modelling of diapirs to predict zones
of likely wellbore instability. An accurate stress model is
therefore useful in the exploration for, and development of
hydrocarbon fields associated with salt diapirs.
With this aim in mind, the objectives of the work
described herein were:
Keywords: South Australia, Officer Basin, numerical
models, geomechanics, viscoelasticity, WIPP-reference
creep law, creep, stress, salt domes, diapirism, borehole
stability, hydrocarbons, petroleum exploration, petroleum
geology
Introduction
Salt diapirs are of considerable economic importance, as
they are associated with oil traps, and their unique physical
properties can also enable storage of various commodities,
such as hydrocarbons and toxic waste (Langer et al 1999).
In the Gulf of Mexico, southern North Sea and the Middle
East, evaporite traps account for up to 60% of hydrocarbon
reserves (Davison et al 1996).
The eastern Officer Basin in South Australia has been
affected by extensive salt diapirism and has the potential
to contain several very large oil fields (Boult and Rankin
2004, Boult 2005). This Neoproterozoic to mid-Palaeozoic
basin covers an area of about 525 000 km2 in western South
Australia and eastern Western Australia (Figure 1). During
the Neoproterozoic, it was part of the Centralian Superbasin
•
•
•
to build a geomechanical model of a diapir
to validate and test the model
to run the model using available data on salt and
surrounding rock mass parameters, and apply commonly
used salt constitutive behaviour models to validate the
130°E
Western Australia
0
Gibson
Sub-basin
w
Yo
ga
al
n
si
ba
b-
Su
ston
King
Defence Science and Technology Organisation, PO Box 1500,
Edinburgh SA 5111. Email: dmitri.koupriantchik@dsto.defence.
gov.au (formerly Australian School of Petroleum, The University
of Adelaide, South Australia).
2
Santos Ltd, GPO Box 2455, Adelaide, South Australia 5001
(formerly Australian School of Petroleum, The University of
Adelaide, South Australia).
3
Petroleum Group, Primary Industries and Resources South
Australia (PIRSA), GPO Box 1671 Adelaide SA 5001 and
Australian School of Petroleum, The University of Adelaide,
South Australia.
4
School of Natural and Built Environments, Division of
Information Technology, Engineering and the Environment,
University of South Australia, Adelaide SA 5001.
1
Shelf
Lennis
Sub-basin
225
450 km
Officer Basin
Northern Territory
South Australia
Waigen
Sub-basin
Birksgate
Sub-basin
ugh
i Tro h
yara oug h
Mun ya Tr roug
n
T
Ma
a
inn
int
W
30°S
30°S
130°E
Figure 1. Location of Officer Basin, showing main tectonic
elements. Box shows location of Figure 3.
Koupriantchik et al
stress values at any significant distance from the diapir
cannot be used for the analysis of risks associated with
borehole stability.
Previous authors modelled salt diapirism as a process
of viscoplastic flow in geological time, and the results
were used to predict various effects of diapirism (Gil and
Jurado 1993, Nalpas and Brun 1993, Poliakov et al 1996,
Davison et al 1996, Barnichon et al 1999). Modelling by
Fredrich et al (2003), based on idealized salt body geometry
undergoing creep within an elastic rock mass, demonstrated
that the interaction of salt and the surrounding rock mass can
lead to significant stress changes in the vicinity of the salt
body. These perturbations in stress may result in increased
risk of drilling failures adjacent to salt diapirs.
The available data on stresses in the immediate vicinity
of diapirs is sparse. Past authors have made qualitative
references to the stress irregularities encountered while
drilling close to salt (Lal 1998, Seymour et al 1993).
Seymour et al mentioned that ‘in formations adjacent to the
flanks of the salt diapir, the in situ stress in the hoop direction
around the salt diapir may be lowered significantly below
the normally stressed value, which occurs at some distance
from the diapir. As this stress is lowered, the difference
between radial and hoop stress increases, thus creating hole
instability and making drilling difficult’. The authors believe
that such qualitative information is insufficient for proper
risk analysis.
Borehole instability and drilling problems associated
with diapirs
Stress-induced wellbore failures are common in the petroleum
industry. Many oil companies have incurred significant
additional costs while drilling in tectonically stressed regions
(in Colombia, northern Argentina, Canada, etc), particularly
in the vicinity of salt domes (Lal 1998). Unscheduled
events, such as stuck pipe and lost circulation, which are
directly related to stability problems, due to uneven stress
concentration around the wellbore, make drilling in such
an environment difficult and costly. Seymour et al (1993)
analysed data from five separate wells close to salt diapir
structures in the Central Graben area of the North Sea. Those
were drilled by Ranger Oil (UK) Ltd between May 1991
and April 1992. The drilling program aimed to explore two
different salt diapirs, but about 26% of operational time was
non-productive. Of this time, borehole instability was the
major contributor (24%), an effect which was compounded
by the open-hole time.
Wellbore instability results from mechanical failure of
the wellbore wall, as a result of interaction between the
in situ stress, rock strength and hole characteristics (eg,
diameter, orientation, drilling practice, etc). As in situ stress
and rock strength cannot be altered, the hole characteristics
greatly influence the effectiveness of a drilling operation.
Good practice in risk reduction involves choosing optimal
mud weights and trajectories for the borehole during predrill
planning sessions. Drilling operators historically tried to stay
away from diapirs as much as possible, but this strategy may
miss commercial quantities of salt-trapped hydrocarbons.
Drilling close to salt diapirs, if properly managed, may prove
very beneficial in finding these accumulations.
Figure 2. Stratigraphic column of the eastern Officer Basin.
•
•
•
results against the findings of other researchers
to formulate and test an algorithm for integration of a
real salt diapir geometry into the model
to establish a procedure to extract stress values at the
points of interest.
to provide basis for recommendations on wellbore
trajectory and possible high risk regions for top seal
breach.
Engineering aspects of salt diapirism
Stress perturbation around a salt dome
The correct estimation of in situ stresses in the near vicinity
of a proposed borehole is very important for the correct
determination of drilling parameters and choice of wellbore
trajectory. The presence of geological inhomogeneities,
such as salt domes, has the potential to result in significant
perturbations of the in situ stress field. Therefore, in situ
Geomechanical modelling of salt diapirs, Officer Basin, South Australia
130°
27°
131°
132°
133°
134°
N
Musgrave Province
gh
rou
iT
ara
M
y
un
28°
Sub-salt
play
Munta-1
gh
Wa
tso
n
rou
aT
y
an
Rid
0
50 km
M
ge
Well with oil shows
Well with no shows
29°
Seismic line
Figure 3. Northeastern Officer Basin (inset from Figure 1) showing locations of seismic lines, wells and Munta-1 (modified after Boult and
Rankin 2004).
Top seal breach analysis
Taking into account the costs commonly associated
with offshore drilling, improvements in the area of
borehole instability would be regarded as beneficial. Such
improvements can be achieved by using information on
diapir-related stress perturbations and planning boreholes so
that their trajectories avoid areas at high risk of borehole
failure as far as is practicable. Better understanding of stress
fields along the proposed borehole path can help an explorer
anticipate potential problems and avoid or mitigate them
proactively. To address this issue, stresses in the rock mass
around a diapir need to be modelled numerically.
Munyarai-1
Ungoolya-1 Lairu-1
It has been shown previously (Castillo et al 2000,
Reynolds et al 2003, Camac et al 2004) that analytical
modelling of stress states on fault planes may reduce the
risk of encountering breached reservoirs in exploration
and appraisal wells. This work concentrated on the risk
of fault reactivation under present-day in situ stress
conditions. High levels of perturbed stress can cause top
seal breach and produce varying local stress fields for a
given structural scenario.
Karlaya-1
Munta-1
near top Trainer Hill Sandstone
near top Acroeillina Sandstone
Giles-1
base Observatory Hill Formation
Relief Sandstone
Tanana Formation
near top Dey Dey Mudstone
near top
Alinga Formation
km
Figure 4. Composite north–south seismic lines intersecting the study area. Salt-withdrawal collapse structures and the Munta salt wall are
clearly evident.
Koupriantchik et al
In the Penola Trough, onshore Otway Basin, South
Australia, the possibility of fault reactivation has been
considered a major risk to trap integrity. In 2001,
Balnaves-1 and Limestone Ridge-1 drilled two structures
that had a low risk of fault breach due to reactivation, but
encountered two partially breached gas columns. Open,
hydraulically conductive fractures, forming a permeable
fracture network, have been interpreted throughout the
brittle top seal in Balnaves-1, based on the Formation
Micro Image Log (FMI), and a vertical rotation of the stress
field was recognised from borehole breakouts (Boult et al
2002). Studies have since been undertaken to integrate the
geomechanics of fault reactivation and cap seal brittleness
(Mildren et al 2002, Dewhurst et al 2003), and provide
a methodology for prospect risking. These previous
authors demonstrated the need to further understand the
geomechanics of structurally complex regions on a regional
scale by using numerical modelling techniques.
Stresses in the rock mass and salt body were initiated
following the methodology of Fredrich et al (2003). Model
boundaries were either fixed laterally (roller boundaries), or
stresses equal to those used in the initialization process were
applied to the vertical boundary planes (stress boundaries).
The bottom boundary of the model was fixed in the vertical
direction in all cases.
Several different sets of rock mass and salt parameters
were used, as well as different constitutive creep models
for salt, as salt masses behave differently from commonly
encountered sediments. Two constitutive creep models of salt
were implemented: a classical viscoelastic (Maxwell) model,
and an empirical creep law, known as the WIPP-reference
creep law, developed to describe the time- and temperaturedependent creep of natural rock salt. This model is described
by Herrmann et al (1980a, b); a different expression of the
same creep law is also given by Senseny (1985).
For each setting, the results of all modelling runs were
very similar and, for σH = σh = 0.7 × σV (normal stress regime),
the results showed no difference from the ones published
by Fredrich et al (2003). Final stress values in salt and rock
mass were independent of salt/rock elastic parameters, or
the choice of salt constitutive model. The effect of boundary
type (stress or fixed) was also negligible, indicating that the
model boundaries were sufficiently far from the diapir, that
boundary effects did not affect the results. However, the
applied stress regime (far field stress) had a very significant
impact on the resultant stress distribution.
On the basis of the above results, it was assumed that
for modeling salt structures that do not have voids within,
or next to them, it is acceptable to assign typical values to
the elastic parameters of the salt and rock mass. It was also
accepted that the simplest constitutive creep model for the
salt (ie viscoelastic) produces realistic modelling results,
requires the least input data (and hence laboratory testing),
and appears to be the least error-prone in numerical codes
(Koupriantchik et al 2005).
Code to enable stress values to be extracted at the points
nominated by the user was written. This code can be used to
examine a particular area of interest, such as trajectory of a
proposed borehole. The information can be used for further
analysis, ie, borehole failure risk analysis, selection of
drilling parameters and regimes, as well as for visualization
in 3D, using specialized software.
GEOMECHANICAL MODELLINg
Modelling generalized shapes
Numerical modelling of the stress state around a salt diapir
was conducted using the three-dimensional, explicit, finitedifference code FLAC3D, by Itasca Consulting Group Inc
(ITASCA 2002). The code simulates the behaviour of threedimensional structures, built of soil, rock or other materials,
that undergo plastic flow when their yield limits are reached.
To analyse the effects of grid zone size, stress regime, and of
salt and surrounding rock mechanical properties, a generic
model of a diapir was built, which featured simplified
axisymmetric diapir geometry (Koupriantchik et al 2004).
Following this work, additional generic shapes were
modelled; these shapes included a sphere (Figure 5) and a
cylindrical column.
Modelling the Munta diapir
4.3980e+006 to 1.5000e+007
1.5000e+007 to 3.0000e+007
3.0000e+007 to 4.5000e+007
The Munta diapir is located in the vicinity of Munta-1 in
the northeastern Officer Basin (Figures 3, 4). It is elongated
in one direction and has steep sides, thus resembling a wall
(Figure 6). Methods of implementing the geometry of a salt
body, such as the Munta diapir, into the FLAC3D model and
the process of acquiring and pre-processing the seismic data,
as well as filtering the surface grid, have been described in
Koupriantchik et al (2004, 2005).
For the convenience of stress initiation in the model, the
model grid axes were orientated along the two horizontal
principal stress directions. The most recent stress orientation
data and an indication of the stress regime in the vicinity of
the Munta site were obtained from the World Stress Map
project (data supplied by Reynolds 2004). Stress magnitude
4.5000e+007 to 6.0000e+007
6.0000e+007 to 7.5000e+007
7.5000e+007 to 8.1691e+007
Figure 5. Von Mises stress (Pa) distribution around a salt sphere
in a rock mass.
Geomechanical modelling of salt diapirs, Officer Basin, South Australia
Depth (m)
N
1 km
0
1 km
-500
-600
-700
-800
-900
-1000
-1100
-1200
-1300
-1400
-1500
-1600
-1700
-1800
a
-1.9326e+007 to -1.9000e+007
Figure 6. Munta diapir; initial seismic interpretation from 2D data.
-1.6000e+007 to -1.5000e+007
-1.9000e+007 to -1.8000e+007
-1.5000e+007 to -1.4000e+007
-1.8000e+007 to -1.7000e+007
-1.4000e+007 to -1.3062e+007
-1.7000e+007 to -1.6000e+007
data for the region is scanty, so for the purpose of the project,
vertical stress was assumed to be the gravitational load:
σZ = σV = ρ × g = 2400 Pa/m,
and horizontal stress gradients were:
σY = σH = 1.2 × σV = 2150 Pa/m and
σX = σh = 0.8 × σV = 1750 Pa/m.
Typical values of rock mass and salt parameters were
used: Young’s modulus E = 6 GPa for rock and E = 31 GPa
for salt (Lama and Vutukuri 1978). The viscoelastic
constitutive model for salt was used, applying a dynamic
viscosity of 3 × 1017 Pa.s. Simulations were run for a model
duration of 1500 years. This was assumed to be enough time
for the deviatoric stress within salt to come sufficiently close
to zero (less than 1 MPa).
b
-1.4984e+007 to -1.4000e+007
-1.1000e+007 to -1.0000e+007
-1.4000e+007 to -1.3000e+007
-1.0000e+007 to -9.0000e+006
-1.3000e+007 to -1.2000e+007
-9.0000e+006 to -8.0000e+006
-1.2000e+007 to -1.1000e+007
-8.0000e+006 to -7.3859e+006
RESULTS AND DISCUSSION OF MODELLING
Results of the Munta diapir modelling showed significant
stress perturbations in the vicinity of the diapir body.
However, the character and degree of the stress changes
varied, depending on the location and depth.
Figures 7, 8, 9 and 10 represent an extract of the program
results. Four maps of stress state are shown at varying depths;
they are Figure 7 (700 m), Figure 8 (1100 m), Figure 9
(1300 m) and Figure 10 (1500 m); the areas highlighted in
grey is the salt diapir.
Figures 7a, 8a, 9a and 10a show distributions of mean
stress, and Figures 7b, 8b, 9b and 10b the distributions of
minimum principal stress at various depths. The distributions
of these stresses are commonly associated with “pooling”
of hydrocarbons, based on the assumption that they migrate
from areas with high levels of mean or minimum principal
stress to less-stressed regions. The results of the modelling
demonstrate that both criteria point at the same areas; ie, the
distributions of mean and minimum principal stress are quite
similar.
The von Mises stress is an indicator of the 3D shear
stress state within a rock mass. Figures 7c, 8c, 9c and 10c
0
c
1 km
3.3390e+006 to 4.0000e+006
8.0000e+006 to 9.0000e+006
4.0000e+006 to 5.0000e+006
9.0000e+006 to 1.0000e+007
5.0000e+006 to 6.0000e+006
1.0000e+007 to 1.1000e+007
6.0000e+006 to 7.0000e+006
1.1000e+007 to 1.2000e+007
7.0000e+006 to 8.0000e+006
1.2000e+007 to 1.2650e+007
Figure 7. Munta salt wall, 700 m depth, plan view. (a) Mean
stress (negative values = compression, Pa). (b) Minimum
principal stresses (negative values = compression, Pa). (c) Von
Mises stresses (Pa).
Koupriantchik et al
a
a
-2.8961e+007 to -2.8000e+007
-2.5000e+007 to -2.4000e+007
-2.8000e+007 to -2.7000e+007
-2.4000e+007 to -2.3000e+007
-2.7000e+007 to -2.6000e+007
-2.3000e+007 to -2.2287e+007
-3.4179e+007 to -3.4000e+007
-3.0000e+007 to -2.9000e+007
-3.4000e+007 to -3.3000e+007
-2.9000e+007 to -2.8000e+007
-3.3000e+007 to -3.2000e+007
-2.8000e+007 to -2.7000e+007
-3.2000e+007 to -3.1000e+007
-2.7000e+007 to -2.6721e+007
-3.1000e+007 to -3.0000e+007
-2.6000e+007 to -2.5000e+007
b
b
-2.9169e+007 to -2.9000e+007
-2.5000e+007 to -2.4000e+007
-2.4000e+007 to -2.3000e+007
-2.3904e+007 to -2.3000e+007
-2.0000e+007 to -1.9000e+007
-2.9000e+007 to -2.8000e+007
-2.3000e+007 to -2.2000e+007
-1.9000e+007 to -1.8000e+006
-2.8000e+007 to -2.7000e+007
-2.3000e+007 to -2.2000e+007
-2.2000e+007 to -2.1000e+007
-1.8000e+006 to -1.7000e+006
-2.7000e+007 to -2.6000e+007
-2.2000e+007 to -2.1000e+007
-2.1000e+007 to -2.0000e+007
-1.7000e+006 to -1.6097e+006
-2.6000e+007 to -2.5000e+007
-2.1000e+007 to -2.0355e+007
0
c
1 km
0
c
1 km
4.2883e+006 to 5.0000e+006
9.0000e+006 to 1.0000e+007
4.1244e+006 to 5.0000e+006
9.0000e+006 to 1.0000e+007
5.0000e+006 to 6.0000e+006
1.0000e+007 to 1.1000e+007
5.0000e+006 to 6.0000e+006
1.0000e+007 to 1.1000e+007
6.0000e+006 to 7.0000e+006
1.1000e+007 to 1.2000e+007
6.0000e+006 to 7.0000e+006
1.1000e+007 to 1.2000e+007
7.0000e+006 to 8.0000e+006
1.2000e+007 to 1.3000e+007
7.0000e+006 to 8.0000e+006
1.2000e+007 to 1.3000e+007
8.0000e+006 to 9.0000e+006
1.3000e+007 to 1.4000e+007
8.0000e+006 to 9.0000e+006
1.3000e+007 to 1.4000e+007
Figure 8. Munta salt wall, 1100 m depth, plan view. (a) Mean
stress (negative values = compression, Pa). (b) Minimum principal
stresses (negative values = compression, Pa). (c) Von Mises stresses (Pa).
Figure 9. Munta salt wall, 1300 m depth, plan view. (a) Mean
stress (negative values = compression, Pa). (b) Minimum principal
stresses (negative values = compression, Pa). (c) Von Mises stresses (Pa).
Geomechanical modelling of salt diapirs, Officer Basin, South Australia
show contours of von Mises stress at various depths. Zones
of high shear stress (up to 50% higher than far field values)
are at the ends of the salt wall and above the top of the diapir,
which indicates that these areas represent higher risk for top
seal breach and borehole instability. The fact that the diapir
is elongated towards the zones of higher von Mises stress
in the model suggests that the diapir has grown faster in the
direction of high shear stress.
Figure 8, at 1100 m, indicates low mean, low minimum
and high deviatoric stresses, all at the east and western tips
of the diapir. This supports the idea of continued growth in
this direction under the current stress regime. As well as this,
around the boundary of the diapir, low mean and minimum,
and slightly raised Von Mises stresses occur as a result of
the irregularity of the diapir curvature and its affect on the
stress distribution.
With increasing depth (Figures 9a–c and 10a–c), the
pattern described for Figures 8a–c continues. The anomalous
low minimum values at the northern boundary of the diapir
decrease in magnitude as the curvature of the diapir walls
decreases with depth.
a
-3.9414e+007 to -3.9000e+007
-3.5000e+007 to -3.4000e+007
-3.9000e+007 to -3.8000e+007
-3.4000e+007 to -3.3000e+007
-3.8000e+007 to -3.7000e+007
-3.3000e+007 to -3.2000e+007
-3.7000e+007 to -3.6000e+007
-3.2000e+007 to -3.1000e+007
-3.6000e+007 to -3.5000e+007
-3.1000e+007 to -3.0743e+007
ConclusionS
The modelling technique passed validation tests using
generic shapes, constitutive behaviour models, discretisation
and stress regime sensitivity. A viscoelastic creep material
model was implemented to ensure realistic behaviour of the
salt. Overall the modelling results show significant stress
perturbations with preferential orientation adjacent to the
Munta salt wall. The predicted distribution of stresses needs
to be taken into account for top seal breach risk analysis
and for planning the exploratory drilling programs. Also,
the modelling identified the areas of high and low mean
and minimum stresses, which may have implications for the
“pooling” of hydrocarbons. Results also indicate that other
target salt structures should be modelled prior to drilling, to
predict shear stress anomalies. The methodology used in this
case study is applicable to salt-dependent hydrocarbon fields
elsewhere, both within Australia and internationally, where
tectonic stress states are well constrained.
b
-3.4448e+007 to -3.4000e+007
-2.8000e+007 to -2.6000e+007
-3.4000e+007 to -3.2000e+007
-2.6000e+007 to -2.4000e+007
-3.2000e+007 to -3.0000e+007
-2.4000e+007 to -2.3380e+007
-3.0000e+007 to -2.8000e+007
Acknowledgements
The authors would like to thank PIRSAfor providing assistance
and the support of Itasca, in particular Mike Coulthard. The
manuscript has benefited greatly from constructive reviews
by Roger Clifton (Northern Territory Geological Survey)
and Torey Marshall (Vibrante Solutions).
0
References
1 km
c
3.5707e+006 to 4.0000e+006
1.0000e+007 to 1.2000e+007
4.0000e+006 to 6.0000e+006
1.2000e+007 to 1.4000e+007
6.0000e+006 to 8.0000e+006
1.4000e+007 to 1.6000e+007
8.0000e+006 to 1.0000e+007
1.6000e+007 to 1.7038e+007
Barnichon JD, Havenith H, Hoffer B, Charlier R, Jongmans D
and Duchesne JC, 1999. The deformation of the EgersundOgna Anorthosite Massif south Norway: Finite element
modelling of diapirism. Tectonophysics 303, 109–130.
Beacom LE, Nicholson H and Corfield RI, 2001. Integration
of drilling and geological data to understand wellbore
instability. paper SPE/IADC 67755, presented at the
SPE/IADC Drilling Conference, Amsterdam, The
Netherlands, February 27–March 1, 2001.
Figure 10. Munta salt wall, 1500 m depth, plan view. (a) Mean stress
(negative values = compression, Pa). (b) Minimum principal stresses
(negative values = compression, Pa). (c) Von Mises stresses (Pa).
Koupriantchik et al
Boult PJ and Rankin L, 2004 Eastern Officer Basin-new
play-sleeping giant?: in Boult PJ, Johns, DR and Lang,
SC (editors) ‘Eastern Australasian Basins Symposium
II, Conference Proceedings.’ PESA Eastern Australasian
Basins Symposium II Adelaide 19–22 September.
Petroleum Exploration Society of Australia, Sydney.
Camac BA and Hunt SP, 2004. Applications of stress field
modelling using the distinct element method for petroleum
production. Asia Pacific Oil and Gas Conference and
Exhibition, Perth. SPE Paper 88473.
Camac BA, Hunt SP and Boult PJ, 2004. Fault and top seal
integrity at relays and intersections, using a 3D distinct
element code – Case studies from the Timor Sea and
Otway Basin. APPEA Journal 44(1), 481–497.
Camac BA, Hunt SP and Bailey, WR, 2005. Distinct
element stress modelling for top seal appraisal in the
Pyrenees-Macedon oil and gas fields, Exmouth Subbasin, Australian North-west shelf: in Chen G, Huang
S, Zhou W and Tinucci J (editors) Proceedings of
Alaska Rocks 2005, the 40th US Symposium on Rock
Mechanics (USRMS): Rock mechanics for energy,
mineral and infrastructure development in the northern
regions, held in Anchorage, Alaska, June 25–29, 2005.
Paper no ARMA/USRMS 05-706. ARMA, University
of Alaska, Fairbanks.
Davison I, Alsop I and Blundell D, 1996. Salt tectonics:
Some aspects of deformation mechanics: in Alsop GI
Blundell DJ and Davison I (editors) ‘Salt tectonics.’
Geological Society, Special Publication 100, 1–10.
Dusseault MB, Maury V, Sanfilippo F and Santarelli FJ, 2004a. Drilling around and under salt: Stresses and
uncertainties: in Yale DP, Willson SM and Abou-Sayed
AS (editors). ‘Gulfrocks 2004. Rock mechanics across
borders and disciplines.’ Proceedings of the 6th North
American Rock Mechanics Symposium (NARMS),
Houston, Texas, June 5–10, 2004.
Dusseault MB, Maury V, Sanfilippo F and Santarelli F-J,
2004b. Drilling through salt: constitutive behavior and
drilling strategies: in Yale DP, Willson SM and AbouSayed AS (editors). ‘Gulfrocks 2004. Rock mechanics
across borders and disciplines.’ Proceedings of the 6th
North American Rock Mechanics Symposium (NARMS),
Houston, Texas, June 5–10, 2004.
Fredrich JT, Coblentz D, Fossum AF and Thorne BJ,
2003. Stress perturbations adjacent to salt bodies in
the deepwater Gulf of Mexico. SPE Annual Technical
Conference and Exhibition, Denver, Colorado, USA,
5–8 October, Paper SPE 84554. Society of Petroleum
Hillis RR, Monte SA, Tan CP and Willoughby DR, 1995.
The contemporary stress field of the Otway Basin, South
Australia: Implications for hydrocarbon exploration and
production. APEA Journal 35(1), 494–506.
Holt J, Wright WJ, Nicholson H, Kuhn-De-Chizelle
A and Ramshorn C, 2000. Mungo field: Improved
communication through 3D visualization of drilling
problems. SPE/AAPG Western Regional Meeting, 19–22
June, Long Beach, California, Paper SPE 62523-MS.
Society of Petroleum Engineers, Richardson, Texas.
Hunt SP and Boult P, 2005. Discrete element stress modelling
in the Otway Basin, Australia: in Boult P and Kaldi J
(editors) ‘Hedberg 2 – Evaluating fault and cap rock
seals.’ Proceedings of the AAPG Hedberg Conference,
December 1–5, 2002, Barossa Valley, South Australia.
American Association of Petroleum Geologists, Hedberg
Series 2, chapter 14.
ITASCA 2002. FLAC3D finite difference code. Version
2.1 User’s manual. ITASCA consulting Group Inc,
Minneapolis, USA.
Jackson MPA and Vendeville BC, 1994. Regional extension
as a geological trigger for diapirism. Bulletin of the
Geological Society of America 106, 57–73.
Koupriantchik D, Hunt SP and Meyers AG, 2004. 3D
Geomechanical modeling towards understanding stress
anomalies causing wellbore instability: in Yale DP,
Willson SM and Abou-Sayed AS (editors). ‘Gulfrocks
2004. Rock mechanics across borders and disciplines.’
Proceedings of the 6th North American Rock Mechanics
Symposium (NARMS), Houston, Texas, June 5–10, 2004.
Koupriantchik D, Hunt SP and Meyers AG, 2005. Generic
and field examples of geomechanical modelling of creep
behaviour in salt diapirs towards predicting localised
stress perturbations: in Chen G, Huang S, Zhou W and
Tinucci J (editors) Proceedings of Alaska Rocks 2005,
the 40th US Symposium on Rock Mechanics (USRMS):
Rock mechanics for energy, mineral and infrastructure
development in the northern regions, held in Anchorage,
Alaska, June 25–29, 2005. Paper no ARMA/USRMS
05-713. ARMA, University of Alaska, Fairbanks.
Lal M, 1998. Drilling wellbore stability and stress magnitudes
and directions: in Müller B, Sperner B and Fuchs, K (editors)
‘Earth stress and industry - The world stress map and
beyond.’ 1st World Stress Map Euroconference, Heidelberg,
Germany, September 3–5, 1998, abstract (available on-line
at http://www.world-stress-map.org), 26.
Lama RD and Vutukuri VS, 1978. Handbook on mechanical
properties of rocks – testing techniques and results 2.
Trans Tech Publications, Clausthal, Germany.
Langer M, 1999. Principles of geomechanical safety
assessment for radioactive waste disposal in salt
structures. Engineering Geology 52, 257–269.
Mildren SD, Boult P and Camac BA, 2002. Risking brittle
failure of caprocks in the Otway Basin, Australia: in
‘Evaluating the hydrocarbon sealing potential of faults
and cap rocks.’ AAPG Hedberg Research Conference,
December 1–5, 2002, Barossa Valley, South Australia,
Abstracts, 108–110.
Morton JGG, 1997. Lithostratigraphy and environments of
deposition: in: Morton JGG and Drexel JF (editors) ‘The
petroleum geology of South Australia, Officer Basin.’
Engineers, Richardson, Texas.
Gil JA and Jurado MJ, 1993. Geological interpretation and
numerical modeling of salt movement in the BarbastroBalaguer Anticline, southern Pyrenees. Tectonophysics
293, 141–155.
Herrmann W, Wawersik WR and Lauson HS, 1980a. Analysis
of steady state creep of southeastern New Mexico bedded
salt. Sandia National Laboratories, Albuquerque, New
Mexico, Report SAND80-0558.
Herrmann W, Wawersik WR and Lauson HS, 1980b.
Creep curves and fitting parameters for southeastern
New Mexico rock salt. Sandia National Laboratories,
Albuquerque, New Mexico, Report SAND80-0087.
Geomechanical modelling of salt diapirs, Officer Basin, South Australia
Senseny PE, 1985. Determination of a constitutive law for
salt at elevated temperature and pressure. American
Society for Testing and Materials, Reprint 869.
Seymour KP, Rae G, Peden JM and Ormston K, 1993.
Drilling close to salt diapirs in the North Sea. Offshore
European Conference, Aberdeen, September 7–10,
1993, paper SPE 26693. Society of Petroleum Engineers,
South Australia Department of Mines and Energy
Resources, Report Book 97/19, 47–86.
Nalpas T and Brun JP, 1993. Salt flow and diapirism
related to extension at crustal scale. Tectonophysics
228, 349–362.
Poliakov ANB, Podladchikov YY, Dawson EC and Talbot
CJ, 1996. Salt diapirism with simultaneous brittle and
viscous flow: in Alsop GI Blundell DJ and Davison I
(editors) ‘Salt tectonics.’ Geological Society, Special
Publication 100, 291–302.
Preece DS and Stone CM, 2003. Use of laboratory triaxial
creep data and finite element analysis to predict
observed creep behavior of leached salt caverns. Sandia
National Laboratories, Albuquerque, New Mexico,
Geoscience and Environment Centre, Underground
Storage Technology Department, Technical Report
SAND82-0678.
Richardson, Texas.
Tingate P and McKirdy D, 2003. Exploration opportunities
in the Officer Basin. Primary Industries and Resources
South Australia, Report Book 2003/1.
Vendeville BC and Jackson MPA, 1992. The rise of diapirs
during thin-skinned extension. Marine and Petroleum
Geology 9, 331–353.
Walter MR, Veevers JJ, Calver CR and Grey K, 1995.
Neoproterozoic stratigraphy of the Centralian Superbasin,
Australia. Precambrian Research 73,173–195.