2011 MRO Template - North Dakota Petroleum Council

Report
20th Annual Williston Basin Petroleum Conference
Russ Buettner
Bakken Asset Team Subsurface Manager
Marathon Oil Corporation
Bismarck, North Dakota
May 23rd, 2012
Understanding Vertical & Horizontal Communication in the Bakken
Agenda
Highlight Marathon’s Bakken results
Why are we focused on lateral and vertical communication?
Marathon’s Data Acquisition Overview
Observations that indicate communication
During both stimulation and production
Key data and analysis used to construct reservoir models
Calibrated simulation results that provide insight toward oil
recovery potential
Invitation to Collaborate
2
Striving for Performance Improvement
MRO Per Well EUR by Year
1200
500
1000
400
800
MRO Per Well Avg IP by Year
35
300
30
Stages (#)
Proppant Density (x 10 lb/ft)
20
600
15
200
400
100
200
0
0
2008
2009
2010
2011
Souce: NDIC database
Frac Fluid (BBL/Ft)
25
BOPD
Gross EUR (MBOE)
600
Industry
Completion Practices (1,600 wells)*
10
5
0
2008
2009
2010
2007
2011
2008
2009
2010
2011
Total Frac Fluid (MBBL)
80
70
60
50
40
30
90 Day Cum Oil vs Frac Fluid*
20
10
0
0
20,000
40,000
60,000
80,000
90 Day Cum Oil (BBL)
Recovery improvements have been made….but do we understand fundamentally why?
Marathon Oil Corporation
* Source: NDIC database
3
2006 – 2011 Dunn County Middle Bakken Wells
2006 – 2007
2006 – 2007
Open Hole Completion Wells
1
Open
Hole Wells
2008
0.9
Staged Wells
0.8
Cumulative Distribution Function
0.7
0.6
2009
Staged Wells
Average Proppant Density (lb/ft):
Why do more stages improve performance?
2008 Stage Completion Wells
-More uniform stimulation along the lateral
Average # of Stages:
Average Proppant Density (lb/ft):
-Increased Stimulated Rock Volume
2009 Stage Completion Wells
-Connections to bounding layers?
Average # of Stages:
Average Proppant Density (lb/ft):
2010
Staged Wells
71
6
144
9
171
2010 Stage Completion Wells
Average # of Stages:
Average Proppant Density (lb/ft):
2011
Staged Wells
19
268
2011 Stage Completion Wells
0.5
Average # of Stages:
Average Proppant Density (lb/ft):
20
228
0.4
0.3
Mean
12 Month Cumulative
Oil Production
(BBL Oil)
0.2
Open
Hole
6 Stage
Completion
9 Stage
Completion
19 Stage
Completion
20 Stage
Completion
41,000
45,000
59,000
88,000
91,000*
0.1
2011 staged wells cumulative oil production based on extrapolation.
0
0
50,000
100,000
150,000
12 Month Cumulative Oil Production (BBL)
200,000
250,000
What is the potential of the Entire Bakken section?
Oil in place in at Typical 1280 acre DSU
Geologic
Layers
Estimated
STOOIP,
MMBLS
Lodgepole
7-9
Upper
Bakken Shale
4-8
Middle
Bakken
8 – 12
Lower
Bakken Shale
12 – 15
Three Forks
10– 15
40-60 MMBbls
•5-15% RF of MB or TF is what we attribute
to a development unit
•But is recovery limited to the horizon that
the lateral is landed in?
5
Conceptual Single Well Recovery of All geologic layers vs. MB only
Model cross-section
5,280ft
5,280 ft
Broad areal drainage
with no vertical connectivity
Limited areal drainage
with increased vertical connectivity
UBS
MB
LBS
TF
MB
High Side - Full Vertical Communication
•
•
Low Side - Vertical Barriers constrain drainage to MB only
All geologic layers are connected through the
natural fracture and fault network
Vertical drainage is more dominant than lateral
• Well EUR40
: 900 – 1,100 MBOE
•
•
Geologic barriers between MB and TF and no
drainage of bounding shales
Lateral drainage is dominant
• Well EUR40
: 300 - 500 MBOE
Geocellular model based simulation with dual porosity and discrete fracture network
6
Conceptual Full Development - What is Optimum Spacing?
MB
TF
Optimum spacing
depends on the degree
of vertical drainage
Full Vertical Communication
•
•
All geologic layers are connected through
fracture networks
Total wells per DSU: 3 MB + 3 TF
Vertical Barriers
•
•
Geologic barriers between MB and TF. No recovery
from shales
Total wells per DSU: 5
3 MB + 5
3 TF
• DSU EUR40
: 4 - 6 MMBOE
• DSU EUR40
: 3
2 – 4.5
3.5 MMBOE
• MB Well EUR40: 700 – 1,000 MBOE • MB Well EUR40: 150200- 250
300 MBOE
7
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Sequence Stratigraphy Model
Core Facies Descriptions
& Petrophysics
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
 3D/3C surface seismic
 VSP (ZO,WA,FO) & Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Rocks & Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics




Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
8
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
Example of Core Description
Vertical Core : Natural Fracture Intercept Rate
(Fracture counts) & Fracture Morphology
 Fracture intensity, orientation, aperture description
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
Fracture intensity
 3D/3C surface seismic
 VSP (ZO,WA,FO) & Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Rocks & Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics




Horizontal Core
Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
9
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
 Borehole image logs
 Fracture counts, orientations
 Geophysics
 3D seismic & VSP’s
 Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Rocks & Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics




Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
Horizontal Image Logs & 3D
Fracture Corridors from Seismic
(curvature calibrated to image Log)
10
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
 3D/3C surface seismic & VSP’s
 Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Rocks & Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics




Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
11
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
 3D/3C surface seismic
 VSP (ZO,WA,FO) & Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Core , Cuttings & Produced Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics




Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
12
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
Marathon Mylo Wolding 14-11H Middle Bakken
Minifrac - G Function
Bott om Hole Calc P ressure (psi)
Smoot hed Pressure (psi)
Smoot hed Adaptive 1st Derivat ive (psi)
Smoot hed Adaptive G*dP/dG (psi)
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
 3D/3C surface seismic
 VSP (ZO,WA,FO) & Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Geochemistry
 Rocks & Fluid Samples
A
8900
A
A
D
D
Time
1
Closure
41.90
BHCP SP DP FE
8303 0.0000.0000.000
D
1000
1
900
8800
800
8700
(64.54, 737.3)
8600
700
600
8500
500
8400
400
(m = 11.42)
8300
300
8200
200
8100
8000
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (DFIT/FET)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 SCAL & Geomechanics
100
(0.002,
(Y
= 0) 0)
0
10
20
30
40
50
60
70
G(Time)
GohWin v1.6.5
11-Jul-10 03:23




Multiple Plug Orientations,
Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)
Permeabilities
13
Bakken Data Acquisition & Integration
 Core Facies Descriptions
 Seq-Strat Model, Facies definition for mapping & modeling
 Petrophysics
 Core fracture descriptions
 Fracture intensity[FI], orientation, relaxed apertures, morphology,
kinematics
 Borehole image logs
 Fracture counts, orientations, apertures, in-situ stress
 Geophysics
 3D/3C surface seismic
 VSP (ZO,WA,FO) & Microseismic
 Lineaments
 Grav & Mag attributes
 Surface Data (Landsat, Digital Elevation Model, etc)
 Rocks & Fluid Samples
 Production Data (Pre- & Post-Stimultation)
 In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
 Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers
in Vertical & Horizontal Wells)
 Special core analysis
 Geomechanical rock properties
 Matrix Permeabilities from whole core
Shear Stress (psi) Increases
 Geochemistry
Normal stress (psi) Increases
14
Increased well density
Preparing for and observing lateral communication during fracs
Decompleting
offsettowells
during fracs
Offset
Lateral Distances
Frac’d Lateral
Gas Profile for Frac’d Lateral
Natural Fracture
Interpreted
~50% of
Near offset
decompleted
wells
see pressure from
offet
stimulation
treatments
“Probable”
Fracture
Fracture
Corridor
Corridors
High Natural
Fracture Density
Assumed
N
Structure from well data
Infill Wells
2000’ Radius
3000’ Radius
Low Natural
Fracture Density
Assumed
Curvature Map Suggestive of Natural
Fracture Density
 Probable fracture corridors interpreted from gas shows and structure maps
 Seismic is also helpful in detecting larger structural events
15
Completion Interference: Three Forks to Middle Bakken
Three Forks Frac Pressures Up Offset MB Well Via Fracture Corridors?
Three Forks
Lateral
Middle Bakken Well
Middle Bakken
Lateral
Middle Bakken Casing Pressure
Fracture
Corridors
700’
Middle Bakken Well
Three Forks Lateral Stage Number
Infill wells
 Casing pressure in a Middle Bakken
well increased from 75 to 3000 psi
during stimulation of adjacent TF well
Three Forks Well
Three Forks Well
 Pressure increases correlated with
stages located in areas with high gas
shows in the lateral
16
Production Interference – Middle Bakken interferes with Three Forks
Vertical Communication Occurs Through Natural Fractures?
Middle Bakken well
Three Forks well
Three Forks well
Lodgepole
Middle Bakken well
Middle Bakken well
Pump installation
Instantaneous
production interference
between nearby MB
and TF wells
Upper Bakken Shale
Middle Bakken
Lower Bakken Shale
Three Forks
500 ft
Middle Bakken well
250 ft
Three Forks well
Production communication
Three Forks well
17
Horizontal Core
Vertical Fractures in a Horizontal Cores
Wide aperture fluorescing fractures in intact core
Slabbed Core
Horizontal Core Slab revealed intense fabric of micro-fractures
Core Depth Increases
Core Depth Increases
18
Outcrops and Conceptual fracture models help explain communication
observed in the field
Bed contained fractures
₋ Fractures related to faults can penetrate
geologic units
₋ Vertical drainage through fault related
fractures should be expected
General outcrop display– not Middle Bakken
19
Integrating natural fractures into a 3 dimensional geocellular model
Regional Fractures
Structural Fractures
ShMax
-Description of pervasive
micro-fracture network
- Description of Regional
Fractures
-Inclusion of structurally related
fractures (swarms-corridors)
Characterization and understanding of all
fractures both natural and induced is needed to
predict performance
Independent Fracture
properties are included in a
dual porosity simulation.
20
Vertical Stress and Hydraulic Fracture Model
Integrating field data to understand fracture growth
INCREASING
PSI
7500
9500
• Vertical stress and pore pressure in 5 layers (LP, UBS,
MB, LBS and TF) were measured with DFIT tests
10550
INCREASING
DEPTH, ft
10575
10600
10625
Closure Pressure
• Results used as inputs to hydraulic fracture simulation
models
Pore Pressure
10650
10675
• Note marginal differences in pore pressure in each layer
that also suggests that the layers are in communication
10700
Predictive fracture models indicate
containment of fracs within zone
LP
MB
TF
• The created Xf that can exceed 1,000’,
but the effective, propped fracture halflengths are <200’
• Model does not include natural fracture
description that can divert fracture
growth vertically
21
Geochemical Data - Stratigraphic intervals in the Bakken
Petroleum System have unique geochemical fingerprints
10,500
10,525
10,550
10,575
10,600
10,625
10,650
10,675
10,700
10,725
-31Geochemical
-30
-29
Signature
• Geochemical signature values can be
sampled initially and over time
• Fluctuation would be indicative of
contribution from bounding layers
22
Individual Well Reserve Evaluations – Which b-factor?
Decline analysis also suggests vertical communication is occuring
b-parameter vs. Time, days
5.0
4.0
4.0
b-parameter
b-parameter
b-parameter vs. Time, days
5.0
3.0
2.0
1.0
3.0
2.0
1.0
0.0
0.0
1
10
100
1000
Time, days
Full vertical communication
10000
1
10
100
1000
10000
Time, days
Vertical barriers between layers
• In this model, geologic units are connected
• With no vertical communication between
vertically through
networksobservations are
layers
in the model
Wellfracture
performance
between
these two cases
• Simulation indicates that b-factors
would
• Simulation
indicates that b-factors will stabilize
indicating
partial vertical
communication
stabilize near 2.
at around 1.0 (isolated MB well)
• This behavior is not being observed in areas
studied
23
Example - Calibrated Single Well Conceptual Model
Pressure depletion
from a frac stage and
through natural fractures
Vertical Permeability
resulting
from fracture networks
• Vertical communication is modeled to occur through structurally related fractures
• Vertical contribution is calibrated with geochemical based production allocation
• Propped hydraulic fractures are assumed to be contained in MB
History matching and
geochem production
allocation helps to
understand how to
constrain vertical
communication in the
static model
Layer
% Contribution
Recoverable
MBOE
Upper layers
5 - 15
50 - 100
MB
75 - 80
500 – 550
Lower layers
15 -20
100 - 200
• EUR40 : 600 -850 MBOE
24
Challenge – How do we collaborate as developers of
the Bakken to improve efficiency and oil recovery?
 Acreage positions are secure in many areas
 Sharing technical understanding and best practices will serve North
Dakota and all of the Bakken stakeholders
History Match - Oil Rate
Oil Prod Rate (STB/DAY), OPRH (STB/DAY)
URAN 31-2H
OPR
OPRH
30 years depletion
600
400
200
Date (YEARS)
Pressure (Fracture Grid)
URAN_MW_FORE_ENHANCE.UNSMRY
16 Jan 2012
TF
MB TF MB
25
Acknowledgments
Marathon Bakken Asset team
 Doyle Adams
 Faisal Rasdi
 Ahmad Salman
Upstream Technology – Bakken Integrated Reservoir
Characterization Team
 Sebastian Bayer
 Steve Buckner
 Jason Chen
 Phillipe Lozano
26

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