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Computer Simulation of Hydrocarbon
Generation, Migration, and Accumulation under Hydrodynamic Conditions --
Examples from the Williston and San Juan Basins, USA*
By
Fred F. Meissner1 and Richard B. Banks2
Search and Discovery Article #40179
Posted November 10, 2005
*Oral Presentation at AAPG
International Conference and Exhibition, October 15-18, 2000, Bali, Indonesia
1Colorado
School of Mines, Golden, CO
2Scientific
Computer Applications, Inc, Tulsa, OK ([email protected])
Abstract
We have
developed a PC-based program that uses basic data to identify and map an area of
source rock maturity and the volumes of oil or gas it may generate, map
secondary migration routes for generated hydrocarbons under hydrodynamic
conditions, and predict the areas and volumes of hydrocarbon accumulation along
a migration path.
Input data
required for mapping the area of source rock maturity and generation volume
includes kerogen type, organic carbon content, source rock thickness, kerogen
transformation ratio, and amount of hydrocarbons retained in the source rock.
Contour 
maps
of these data are generated and integrated on the PC.
Input data
required for mapping secondary hydrocarbon migration paths within a carrier/
reservoir unit charged by a mature source rock include datum elevations on top
of the reservoir, pressure data, and reservoir fluid densities. Structure and
groundwater potentiometric surface maps may be modified by a fluid density
controlled "tilt amplification factor" to create "phantom" hydrocarbon-water
contact (HWC) datum elevation contour map. The intersection of contours on the
structure and phantom HCW maps may be used to create contours of equal
hydrocarbon potential energy that control migration paths and sites of potential
entrapment.
|
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
uAbstract
uTechnique
uData
used
uPrimary
contour maps
uBasic
relations
uWilliston
Basin
uFigures
1-12
uBakken
Shale
uHC
potential
uOil
generated
uOil
expelled
uSan
Juan Basin
uFigures
13-19
uHubbert’s
relation
uSummary
|
•
Technique allows use of primary contour maps to generate secondary maps.
•
Primary maps may come from disparate data from different locations or
sources.
•
One can use published contour maps for which no primary supporting data
are available.
•
Source Rock Data:
–
Total Organic Carbon (TOC), Thickness, Kerogen Type, Maturity (Ro),
Transformation Ratio, Solvent Extractables
•
Structural Data
•
Hydrodynamic Data
–
Pressures or Hydraulic Heads
–
Fluid Densities
•
Total Organic Carbon (TOC)
•
Thickness
•
Maturity (Ro)
•
Fraction Of Ultimate Generation (Transformation Ratio)
•
Non-expelled HCs
•
Structure Map
•
Potentiometric Surface Map In Reservoir/carrier
Vg= A*T*TOC*Q*F
WHERE
Vg = Volume Of Generated HCs
A = Area, Acres
T = Thickness, Feet
TOC = Total Organic Carbon, Fraction
Q = Ultimate Yield, Bbl/acre-foot
-Function of Kerogen Type
F = Ultimate Generation
-Function of Source Rock
Maturity (Ro)
Ve = Vg
- Vne
WHERE
Ve = Volume of Expelled HCs
Vg = Volume of Generated HCs
Vne = Volume of Non-Expelled HCs
Volumes calculated by computer contouring and integration.
Williston Basin (Madison- Bakken Oil System)
(Figures 1-12)
Figures 1-12
Click to
view sequence of Williston Basin maps (Figures 3-8, 11).
Bakken Shale
With Bakken
Shale as source rock, Type II oil-generating kerogen yields 3200
Bbl/acre-foot (Figure 2).
Gross Area (AC) = 25,000,000
Gross Volume (AC/FT) = 603,000,000
Net Volume (AC/FT) = 25,000,000
25,000,000 * 7758 * 3200/7758=80 Billion Barrels
Present day volume of oil generation is 32 billion barrels.
Volume of
expelled oil is 28.8 billion barrels.
San Juan Basin
(Mesaverde Gas System)
Click to view sequence of San Juan Basin maps
(Figures 15-17).
DX/DY
= TAF X
DX/DZ
WHERE
TAF =
water density
water density – HC density
BASIC
RELATION:
PEhc = TME - SE
WHERE
PEhc = Potential energy factor for HC
TME
= Tilt Map* contour elevation
SE = Structure map contour elevation
Computer assisted intercept solutions for contour maps of certain key
parameters may be used to construct maps depicting generation, migration
and accumulation patterns and amounts.
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