Use of Microseismic in Monitoring Hydraulic Fractures in the Bakken ...
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Use of Microseismic in Monitoring Hydraulic Fractures in the Bakken Formation, North Dakota, USA* Gary Forrest1, Tom Olsen1, Aleksey Kazantsev1, Ernest Gomez1, Tim Dombrowski1, and Wayne Rowe2 Search and Discovery Article #110090 (2009) Posted July 25, 2009
*Adapted from oral presentation at AAPG Annual Convention, Denver, Colorado, June 7-10, 2009 1
Schlumberger Data and Consulting Services, Greenwood Village, CO ([email protected]) Schlumberger Water Management Services, Denver, CO
2
Abstract The Mississippian-Devonian Bakken Formation is a relatively tight mixed carbonate – clastics sequence in the Williston Basin of North Dakota. Although production can exceed 1000 BOPD, hydraulic fracturing is necessary to induce economic production. Until recently a great degree of uncertainty has existed regarding how the Bakken behaves during fracturing. In late 2007 seven (7) operators along with Schlumberger created a consortium that used the best available technologies to optimize understanding of certain geologic, drilling, and completion principles that affect production. As part of this, three (3) horizontal wells (each 4000 feet in length) were drilled in an eastwest direction, 1500 feet apart into the Middle Bakken Member. An array of 15 triaxial geophones, with 100 feet between each sensor set, was placed into the middle lateral (Nesson State 42X-36) to monitor the microseismic activity during the hydraulic fracturing of the two (2) outside wells. Different hydraulic fracturing methods were tried in each of the wells, ranging from a single treatment in the northern lateral (Nesson State 41X-36) to a six (6) staged treatment with swell packers in the southern lateral (Nesson State 44X-36). The microseismic events were integrated with the geologic understanding of the area, radioactive and chemical tracers, and reservoir simulation to develop a robust interpretation of effectiveness of the hydraulic fracture treatments.
Reference LeFever, Julie, 2005, Oil production from the Bakken Formation: A short history: North Dakota Geological Survey newsletter, v. 32, no. 1, p. 5-10.
Microseismic Monitoring of Hydraulic Fractures: Bakken Formation, North Dakota Gary Forrest, Tom Olsen, Aleksey Kazantsev, Ernest Gomez, Tim Dombrowski, Wayne Rowe, Alex Perakis Schlumberger Data and Consulting Services, Denver Denver AAPG, June 9, 2009
Research Concept
Producer, NS 41X
~1500 ft Monitoring Well, NS 42X
~1500 ft
Producer, NS 44X
• Drill three wells with single 4000 ft. laterals. • Use the most advanced technology available. • Design to support microseismic monitoring from the middle lateral.
Nesson State 41X
Nesson State 42X
Nesson State 44X
Bakken Stratigraphy Anoxic Marine
Upper Bakken
Laterals Middle Bakken
Marginal Marine Offshore Complex
Bakken Carbonate
Devonian
Clastic Clay Lower Bakken
Mississippian
Lodgepole
Anoxic Marine Pyrite
Three Forks
(LeFever, 2005)
Three Additional Seismic Systems Installed and Monitored Separately • Department of Energy (DOE) System: 3 bore holes, each with 3 sets of triaxial sensors grouted every 500 feet; maximum depth ~1500 feet • Terrascience: 18 bore holes with triaxial sensors grouted at ~300 feet • Microseismic, Inc: 24,000 single component geophones planted on the surface
NS 42X Pierre Shale
• Severe signal attenuation was a problem for the DOE and Terrascience. 10,000 ft MD
Bakken
• They did not detect any seismic events, despite the quality and sensitivity of their instruments and deep installations.
3-D Seismic Transect
Seismic Signal P-Wave Arrival Time
S-Wave Arrival Time Amplitude
S-P = Delta T
Milliseconds
From Geology Labs Online, University of California
• Each seismic signal is unique P
S
• All have P and S wave arrivals
Perf Shot on May 20 at 23:32:17, 2008 GMT P
S
Known Location and Time
P, Sh, Sv
44
P
S
Recorded Seismic Event NS 44X
P with Both Shear Waves
NS 41X
All potential events before data editing
NS 44X
NS 41X: Map View
• Locations are based on P and S arrival times and measured P and S velocities ONLY. • There are no bulk shifts applied to these event locations.
NS 41X: Looking North
X-Linked Gel: Height Growth
NS 41X vertical growth at onset of X-Linked Gel
e Profile
0
0 0
Frac Half Length Propped Frac Half Length
0
0
Frac Half Length Propped Frac Half Length
0
0
0
0
View to North
0
0
0 0 0
0
Slickwater Model
0 0
X-Linked Model
NS42X-36
NS44X-36
NS 44X: Map View
NS 44X: Looking North
NS 44X Comparison Stage 3 Slickwater
Stage 3 X-Linked Gel
NS 44X, Stage 3: Radioactive Tag N S 4 4 X -3 6 H G R _ M W D
GR
Stage 6
M D
5 5 6 7 .5 3 6 7
Vol Carbonate
T X S P _ A N IS O
9 7 5 0 .8 3 0 5
TXSP-Aniso
0
[M D ] 9 0
Fractures
0 .0 0
S B F
1 0 0 0 .0 0
0 .0 0
Antimony
S C F
1 0 0 0 .0 0
0 .0 0
Scandium
1 1 0 0 0
10900’
1 5 0 .0 0
0 5 0 0
0 .0 0
11250’ 1 1 5 0 0
11500’
Stage 5 1 2 0 0 0
12200’ 12500’
1 3 0 0 0
Stage 3
1 2 5 0 0
Stage 4
13150’ 1 3 5 0 0
13450’
Stage 2 13800’ 1 4 0 0 0
Stage 1
1 4 5 5 1
Antimony
Scandium
Iridium
In Target
Perforations
Packers
IR F
1 0 0 0 .0 0
Iridium
Antimony Tracer SBF
Packers
Map View
NS 44X Chemical Tracer Flow Back In d ivid u al & T o tal T racer C o n cen tratio n , p p b
600
500
400
Stage 3
Production Correlates to the Number and Distribution of Events
300
200
Other Stages
100
0 0
500
1000
1500
2000
2500
3000
Cumulative Flow back Volume, bbl St age 1
St age 2
St age 3
St age 4
St age 5
St age 6
Tot al ppb
3500
Production Model Fracture Fit
Model Validation: Well Oil Production Rate NS 41X
NS 44X
Key Observations • Seismic events show a strong correlation to the changes in frac fluid. • Production history shows a strong correlation to the number and distribution of seismic events for each stage. • History match from the seismic based reservoir model was nearly perfect; requiring only a 10% adjustment to permeability for a fit.
Use of Microseismic in Monitoring Hydraulic Fractures in the Bakken Formation, North Dakota, USA* Gary Forrest1, Tom Olsen1, Aleksey Kazantsev1, Ernest Gomez1, Tim Dombrowski1, and Wayne Rowe2 Search and Discovery Article #110090 (2009) Posted July 25, 2009
*Adapted from oral presentation at AAPG Annual Convention, Denver, Colorado, June 7-10, 2009 1
Schlumberger Data and Consulting Services, Greenwood Village, CO ([email protected]) Schlumberger Water Management Services, Denver, CO
2
Abstract The Mississippian-Devonian Bakken Formation is a relatively tight mixed carbonate – clastics sequence in the Williston Basin of North Dakota. Although production can exceed 1000 BOPD, hydraulic fracturing is necessary to induce economic production. Until recently a great degree of uncertainty has existed regarding how the Bakken behaves during fracturing. In late 2007 seven (7) operators along with Schlumberger created a consortium that used the best available technologies to optimize understanding of certain geologic, drilling, and completion principles that affect production. As part of this, three (3) horizontal wells (each 4000 feet in length) were drilled in an eastwest direction, 1500 feet apart into the Middle Bakken Member. An array of 15 triaxial geophones, with 100 feet between each sensor set, was placed into the middle lateral (Nesson State 42X-36) to monitor the microseismic activity during the hydraulic fracturing of the two (2) outside wells. Different hydraulic fracturing methods were tried in each of the wells, ranging from a single treatment in the northern lateral (Nesson State 41X-36) to a six (6) staged treatment with swell packers in the southern lateral (Nesson State 44X-36). The microseismic events were integrated with the geologic understanding of the area, radioactive and chemical tracers, and reservoir simulation to develop a robust interpretation of effectiveness of the hydraulic fracture treatments.
Reference LeFever, Julie, 2005, Oil production from the Bakken Formation: A short history: North Dakota Geological Survey newsletter, v. 32, no. 1, p. 5-10.
Microseismic Monitoring of Hydraulic Fractures: Bakken Formation, North Dakota Gary Forrest, Tom Olsen, Aleksey Kazantsev, Ernest Gomez, Tim Dombrowski, Wayne Rowe, Alex Perakis Schlumberger Data and Consulting Services, Denver Denver AAPG, June 9, 2009
Research Concept
Producer, NS 41X
~1500 ft Monitoring Well, NS 42X
~1500 ft
Producer, NS 44X
• Drill three wells with single 4000 ft. laterals. • Use the most advanced technology available. • Design to support microseismic monitoring from the middle lateral.
Nesson State 41X
Nesson State 42X
Nesson State 44X
Bakken Stratigraphy Anoxic Marine
Upper Bakken
Laterals Middle Bakken
Marginal Marine Offshore Complex
Bakken Carbonate
Devonian
Clastic Clay Lower Bakken
Mississippian
Lodgepole
Anoxic Marine Pyrite
Three Forks
(LeFever, 2005)
Three Additional Seismic Systems Installed and Monitored Separately • Department of Energy (DOE) System: 3 bore holes, each with 3 sets of triaxial sensors grouted every 500 feet; maximum depth ~1500 feet • Terrascience: 18 bore holes with triaxial sensors grouted at ~300 feet • Microseismic, Inc: 24,000 single component geophones planted on the surface
NS 42X Pierre Shale
• Severe signal attenuation was a problem for the DOE and Terrascience. 10,000 ft MD
Bakken
• They did not detect any seismic events, despite the quality and sensitivity of their instruments and deep installations.
3-D Seismic Transect
Seismic Signal P-Wave Arrival Time
S-Wave Arrival Time Amplitude
S-P = Delta T
Milliseconds
From Geology Labs Online, University of California
• Each seismic signal is unique P
S
• All have P and S wave arrivals
Perf Shot on May 20 at 23:32:17, 2008 GMT P
S
Known Location and Time
P, Sh, Sv
44
P
S
Recorded Seismic Event NS 44X
P with Both Shear Waves
NS 41X
All potential events before data editing
NS 44X
NS 41X: Map View
• Locations are based on P and S arrival times and measured P and S velocities ONLY. • There are no bulk shifts applied to these event locations.
NS 41X: Looking North
X-Linked Gel: Height Growth
NS 41X vertical growth at onset of X-Linked Gel
e Profile
0
0 0
Frac Half Length Propped Frac Half Length
0
0
Frac Half Length Propped Frac Half Length
0
0
0
0
View to North
0
0
0 0 0
0
Slickwater Model
0 0
X-Linked Model
NS42X-36
NS44X-36
NS 44X: Map View
NS 44X: Looking North
NS 44X Comparison Stage 3 Slickwater
Stage 3 X-Linked Gel
NS 44X, Stage 3: Radioactive Tag N S 4 4 X -3 6 H G R _ M W D
GR
Stage 6
M D
5 5 6 7 .5 3 6 7
Vol Carbonate
T X S P _ A N IS O
9 7 5 0 .8 3 0 5
TXSP-Aniso
0
[M D ] 9 0
Fractures
0 .0 0
S B F
1 0 0 0 .0 0
0 .0 0
Antimony
S C F
1 0 0 0 .0 0
0 .0 0
Scandium
1 1 0 0 0
10900’
1 5 0 .0 0
0 5 0 0
0 .0 0
11250’ 1 1 5 0 0
11500’
Stage 5 1 2 0 0 0
12200’ 12500’
1 3 0 0 0
Stage 3
1 2 5 0 0
Stage 4
13150’ 1 3 5 0 0
13450’
Stage 2 13800’ 1 4 0 0 0
Stage 1
1 4 5 5 1
Antimony
Scandium
Iridium
In Target
Perforations
Packers
IR F
1 0 0 0 .0 0
Iridium
Antimony Tracer SBF
Packers
Map View
NS 44X Chemical Tracer Flow Back In d ivid u al & T o tal T racer C o n cen tratio n , p p b
600
500
400
Stage 3
Production Correlates to the Number and Distribution of Events
300
200
Other Stages
100
0 0
500
1000
1500
2000
2500
3000
Cumulative Flow back Volume, bbl St age 1
St age 2
St age 3
St age 4
St age 5
St age 6
Tot al ppb
3500
Production Model Fracture Fit
Model Validation: Well Oil Production Rate NS 41X
NS 44X
Key Observations • Seismic events show a strong correlation to the changes in frac fluid. • Production history shows a strong correlation to the number and distribution of seismic events for each stage. • History match from the seismic based reservoir model was nearly perfect; requiring only a 10% adjustment to permeability for a fit.
