8. Migration & Fluid flow
Application of Darcy, Flowpath, and Percolation Models
to Petroleum System Models
Darcy Flow Modeling
Concept: Based on equations of flow through porous media
Advantages:
• Good definition of carrier and seal system
• Easy inclusion of complex migration and transport processes such as
multi-phase migration, gas diffusion and PVT controls
• Only method that fully integrates pressures into the modeling process
Disadvantages:
• Cannot accurately handle accumulations and breakthroughs
• Long processing times
• In order to obtain acceptable processing times, models must be
simplified with a loss of geometric information
Leakage
re-migration
Migration
Migration from the deep kitchen
Pore space saturation with HC liquids
Darcy Law Capillary entry pressure
Migration from the deep kitchen
Pore space saturation with HC liquids
Darcy Law in low permeability environment
Tscherny et al, 2004
Concept: Geometrical surface analysis (buoyancy driven migration)
Advantages:
• Fast processing
• High resolution modeling
• Accurate reservoir geometries can be included
Disadvantages:
• Incomplete physical model of petroleum migration
• Arbitrary definitions of the migration system, e.g. of seals
• Not suitable for complex migration processes
• Misleading simplicity
Flowpath (= ray tracing) Modeling
Import structural map – show fetch areas
Flowpath
Poloygon of active source kitchen – inject oil and gas generated
Flowpath
Oil migration, accumulation and spills
Flowpath
Liquid (oil) and vapour (gas) migration, accumulation and spills
Migration – Flowpath
Gas
Oil & Gas
Flowpath – Buoyancy Driven – Following Topography
Fault Assignments in 3D
Layer-Maps
Properties are different for:
- Geological Ages
- Geological Layers
Deep Source Carrier Shallow Reservoir
Main Faults from
Source to Seals
Open 37-14 Mabp,
Closed 14-0 Mabp
Inactive Faults
Local Faults
Mainly Closed
Faults as conduits or seals
Closed faults scenario Open faults scenario
efficient carrier
fast migration
FLOWPATH
source
units
petroleum system component
migration process
MIGRATION MODELING METHOD
expulsion (up)
DARCY or FLOWPATH
the source system:
the reservoir system:
expulsion (down!)
DARCY
the carrier system:
inefficient carrier
slow migration
DARCY
reservoir body
equilibrium state
FLOWPATH
seal
loss
DARCY
Different simulation methods (Darcy,
Flowpath) can be used to handle
different processes in the petroleum
system:
Hybrid Migration Modeling:
The Petroleum System
Overpressure
HC Generation / Migration
Late Neogene
Rift stage source rock with transformation ratio
accumulation bodies, vectors and flow paths.
Migration – hybrid method
High Permeability
Facies
- Flowpath Area
Low
Permeability
Facies
- Darcy Area
Carrier Rock Facies
Known
accumulations
occur
in the
shallow
post- rift
structures
Tscherny et al, 2004
properties and compositions to be more
accurately determined for different
reservoir depths!
8. n-Component / Phase Modeling:
flash calculations
Component Mol% Mass%
CO2 0.91 0.43
N2 0.16 0.05
C1 36.47 6.24
C2 9.67 3.10
C3 6.95 3.27
iC4 1.44 0.89
nC4 3.93 2.44
iC5 1.44 1.11
nC5 1.41 1.09
C6 4.33 3.97
C7+ 33.29 44.71
?
p
T
p, T Separator Prediction of
GOR, API Density
Liquid
Vapour
HC Components HC Phases
Fluid Composition and Phase prediction
Multicomponent pvT-Analysis
Component Mol% Mass%
CO2 0.91 0.43
N2 0.16 0.05
C1 36.47 6.24
C2 9.67 3.10
C3 6.95 3.27
iC4 1.44 0.89
nC4 3.93 2.44
iC5 1.44 1.11
nC5 1.41 1.09
C6 4.33 3.97
C7+ 33.29 44.71
?
Volume
Liquid, Vapour, (Water)
Phase
Composition
Liquid, Vapour, (Water)
Phase
Density
Liquid, Vapour, (Water)
Phase
Viscosity
Liquid, Vapour, (Water)
Phase
p
T
p, T Separator
Prediction of
GOR, API Density
Liquid
Vapour
HC Components HC Phases
Multicomponent pvT-Analysis
LIQUID
VAPOUR (GAS)
C...Critical Point
Temperature
Pressure
T...Triple Point
A
B C
pT Diagram of Pure Substance
(single component)
LIQUID
VAPOUR
(GAS)
C...Critical Point
Volume
Pressure
A B
T = Tc
T < Tc
T > Tc
pV Diagram of Pure Substance
(single component)
pT Diagram of a Mixture (two components)
Temperature
Pressure
LOW PRESSURE
HIGH PRESSURE
100%
0 % Vap
Liq
Bubble
point line
Dew point line
LIQUID
VAPOUR
(Gas)
Critical
condensation
temperature
Critical Point
CO2
N2
C1
C2-C4
C5-C6
C7-C13
C13+
Pseudo-
Component
Gas
Pseudo-
Component
Oil
Bubble and Dew Point Curves
Gas Component
Oil Component
Gas Component
Oil Component
Vapour Phase
Liquid Phase
Vapour Phase
Liquid Phase
Components: Pseudo- Phases:
Components:
Symmetrical Black Oil Model (SBO)
Deep pT conditions
Flash Calculations
Surface conditions
Flash Calculations
2-D 2-phase / n-component modeling:
OIL
Composition of
1-Phase fluid at
reservoir
conditions
Composition
of the same
fluid flashed
to surface
conditions
(GOR = 305
m3/m3)
Flash calculations
Background
Ro (%)
vitrinite
HC Quality Prediction
Accumulated
HC’s
What it looks like
when it comes to the surface
Flashed to surface
conditions
Predicts API=35
GOR=39
Tscherny et al, 2004
Component Tracking
Component / Phase relationships
calculated by flash calculations.
Components from each source rock
can be viewed in each accumulation.
Phase /
Component
information for
accumulation
Flash calculations
3D 3-phase / n-component modeling:
View of the
hydrocarbon
accumulation
with
volumetrics,
properties,
phase and
component
information Flashed to
surface
conditions
At reservoir
conditions
110 Ma
102
98
94
86
65
60
55
40
30
21
16
8
present
Dynamics of Accumulation and Phase Partitioning
Lampe et al, 03
Prediction: Volume/Phase/Composition
Lampe et al, 03
Example: 3-D Fluid Flow Models
Alaska North Slope
Summary - Migration
Progress in Basin Modeling
• From basin to reservoir scale
• Thermal histories -> Fluid Flow -> Component /
Phase Composition (pVT)
• Prospect appraisal (ranking and risking) -> product
predictions to regional reserves assessments
56 ma50 ma46 ma25 ma19 ma13 ma6.4 ma0.0 ma
Tscherny et al, 2004
Juraj Francu jfrancu@egi.utah.edu
Gracias por su atención