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Some Applications of Geomechanics in Petroleum Engineering: - Australasian Stress Map

This document discusses various applications of geomechanics in petroleum engineering such as understanding in-situ stresses, induced stresses from activities like drilling and production, wellbore stability, hydraulic fracturing, and how faults and fractures impact operations. Mechanical properties can be estimated from logs and changes in pore pressure or temperature can influence stresses. Directional drilling response and casing collapse are also covered.

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150 views10 pages

Some Applications of Geomechanics in Petroleum Engineering: - Australasian Stress Map

This document discusses various applications of geomechanics in petroleum engineering such as understanding in-situ stresses, induced stresses from activities like drilling and production, wellbore stability, hydraulic fracturing, and how faults and fractures impact operations. Mechanical properties can be estimated from logs and changes in pore pressure or temperature can influence stresses. Directional drilling response and casing collapse are also covered.

Uploaded by

wiwinwdja
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Some applications of Geomechanics in

Petroleum Engineering

Australasian Stress Map


Blacktip field
location and
regional
stress

Indicates
SHmax
direction

Reference: www.asprg.adelaide.edu.au/asm/

Vertical wells BTN-1, BT-1 and BT-2 are drilled vertical wells
BTP-1 and BTP-2 are deviated planned wells
F1 to F4 are major faults in the area

BTN-1
F1

F2

F4
BTP-2

F3
BT-2

BT-1

BTP-1

Local stresses around the wellbore maybe completely


different due to the existence of faults or many other factors

E, UCS, ,
C, ,

Mechanical
properties

Petrophysical logs carry


information regarding
Mechanical properties
and stresses.
For example, the larger
the sonic velocity or the
lesser the porosity the
stronger
g the rock will be

Principal stresses in the field


before drilling, production
(depletion) or injection, etc

h
H

Induced stresses in the field


before drilling, production
(depletion) or injection, etc

Tangential (hoop)
stress ()

h
H

Radial
stress (rr)

Hydraulic Fracturing
Deep fractures tend
to be vertical; shallow
fracs often horizontal

Deep
well

Shallow
well

1
High
compressive
stress

Preferred
fracture
planes

Hydraulic Fracturing
v
h

Stable Mud Weight Windows determination

Pore
Pressure
Gradient

Kick
Low

Breakout
Pressure
Gradient

Borehole
Breakout

Breakdown
Pressure
Gradient

Minimum
Stress
Gradient

Safe/Stable
Mud Weight

Loss

Drilling Induced
Fracture
High

Directional Drilling

v
h

H
v> H > h

Normal Stress Regime

Fault/fracture reactivation during


drilling

Drilling fluid invasion


into the fracture plane
changes the normal
stress magnitude

Fault/fracture Morphology
Surface roughness affects
hydro-mechanical response
of a fracture significantly

Pore pressure
Total Stress (v)

v v PP
Total Stress= effective stress (Grains)+Pore pressure (Fluid)

Stress Transfer to Over- and Underburden


Wellbore

h concentration
Far-field stresse
es

h stress trajectories

final
h

h along
wellbore

Depleted
p
zone

initial
h

15

Temperature Gradients
d
A

Fluid injection
(hot or cold)

Low k Shale

Conductive heat flow


Convective heat flow
High k

T
B

Reservoir
Shale

+/- T
+/-T
B

T
d
16

Casing collapse due to depletion/injection


induced stresses

Cased, cemented
wellbore
Ductile
interval

Hard interval
Collapsed
casing
Damaged
cement

Fault/fracture reactivation due to


depletion/injection induced stresses

Production

v = 1
hmin = 3

n = n - p

Applications
Understanding In-situ stresses and how to
determine them
The impact of fractures and discontinuities at
different scales (e.g. faults) on drilling and
production
Estimation of formation Mechanical properties from
logs
Estimation of induced stresses after any activity
(drilling, injection or depletion, etc)
Hydraulic Fracturing, Stable Mud Weigh Windows
determination/Wellbore stability

How pore pressure changes can influence the


stresses?
How directional wells respond to the in-situ
stresses?
Fault/fracture reactivation during drilling
Depletion or injection induced stresses
Temperature induced stresses
Casing collapse
Fault/fracture
Fault/fracture reactivation within the reservoir or
over/under burden

10

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