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Microseismic Monitoring:Engineering Value and Validation
Norm WarpinskiPinnacle – A Halliburton Service
2© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Microseismic Monitoring – An Engineering Tool Microseismic monitoring is a
valuable tool for optimizing– Well layout (trajectory)– Well spacing– Stage lengths– Perf clusters and/or valves & packers– Stimulation design– Fracture height and length– Complexity– SRV– Diverter behavior– Fault interactions & geohazards– Calibrated fracture model Environmental issues
– Fracture height growth (aquifers)– Seismicity
SPE 145463, Mayerhofer et al.
Marcellus shale
3© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Downhole microseismic monitoring Array of receivers
– Positioned in nearby well
– Approximately at the depth of the treatment
3-component geophone systems ¼ to ½ msec sampling
State-of-the-art microseismic receiver arrays
Fiber-optic wirelines
Wall-lock clamped tools
Array apertures of 500 – 1,500 ft
Vertical Up V
H2 H1
Clamp ArmIn Back
Tri-Axial Sensors (Geophones)
Calibrated Velocity Model
4© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Fracture Behavior: Wide Variations Sandstones
– Relatively planar– Piceance basin
Mesaverde example Barnett Shale
– Intrinsic complexity• Low stress bias• Weak natural fractures
– Enhanced by slick water stimulations
Other shales and most carbonates?– Full spectrum of
behavior
-200
0
200
400
600
800
1000
-600 -500 -400 -300 -200 -100 0 100 200
Sout
h-N
orth
(m)
West-East (m)
Barnett
Mesaverde
SRV
Planar
5© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Microseismicity Distribution
Microseisms are distributed approximately proportionately:– Near tips (length and height)– Around fracture face
-60
-40
-20
0
20
40
60
0 20 40 60 80 100 120 140
Dept
h fro
m ce
nter
of p
erfs
, m
Time, min
-400
-300
-200
-100
0
100
200
300
400
0 20 40 60 80 100 120 140
Dist
ance
alon
g fra
ctur
e len
gth,
m
Time, min
-200
0
200
400
600
800
1000
1200
-1400 -1200 -1000 -800 -600 -400 -200 0 200
North
ing,
m
Easting, m
SPE 148780 Canadian sedimentary basin example
Interior eventsTip events
Interior eventsTip events
6© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Fracture StabilityPlan View
Shear zones
max
min
Compressive zone
All stresses compressiveIncreased frictional forcesDecreased shearSTABILIZED
Tensile zone
All stresses tensile:Reduced frictional forcesIncreased shearDESTABILIZED
x
y
x
y
Leakoff effects into natural fractures
7© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Hydraulic Fracturing and Microseismicity Microseisms
– Fracture tip• Tensile events?• Shear events ahead of
fracture– Leakoff into natural
fractures• Shear events
– Increased pressure– Slippage on natural
fractures• Tensile events
– Fissure opening– Network
• Combination of both of above
8© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Where Would These Microseisms Likely Occur? Intersections of natural
fractures, faults, and bedding planes provide suitable sites for shear processes
Coal
DOE mineback testsSPE 15258
&SPE 16422
9© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Fracture Behavior in Multi-Stage, Multi Cluster Completions
10© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
-400
-300
-200
-100
0
100
200
300
400
-300 -200 -100 0 100 200 300
Nor
thin
g, m
Easting, m
Stage 1Stage 2Stage 3Stage 4Stage 1Stage 2Stage 3Stage 4
Monitor well
Treatment well #1
Treatment well #2
Microseismic Interpretation Understanding biases and
artifacts– Distance limitations– Radial appearance– Noise hindrance– Fracture effects
-1400
-1200
-1000
-800
-600
-400
-200
0
200
-800 -600 -400 -200 0 200 400
North
ing,
m
Easting, m
Monitor well
Stage 3:Minimal noise
Stage 6:Fracture intersects
monitor well
Stage 8:Excessive noise
11© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
-50
0
50
100
150
200
250
-150 -100 -50 0 50 100
SOUT
H-NO
RTH
(m)
WEST-EAST (m)
M-Site Length & Azimuth Validation Intersecting Well
Drilled Prior To Fracturing Microseismic
Events Recorded During Fracturing & Compared At Time When Pressure Began To Increase In The Intersecting Well
Primary validation experiments:M-Site – microseismic, tiltmeters, intersection wells, tracers, pressure interferenceMounds Drill Cuttings – microseismic, tiltmeters, intersection wells, tracersMitchell Barnett – microseismic, surface & downhole tiltmeters, offset wells
MWX-3
MWX-2
Intersection well
Point of intersection
12© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
4200
4300
4400
4500
4600
4700-10 -5 0 5 10
DE
PTH
(ft)
TILT (microradians)
FE -- 67 ft5B data6B data
0 20 40 60
4200
4300
4400
4500
4600
4700
Frequency
4400
4500
4600
4700-300 -100 100 300 500
DEP
TH (f
t)
ALONG FRACTURE LENGTH (ft)
B SAND
Fracture Height Versus Downhole Tiltmeter Data M-Site
– Monitoring with 6 tiltmeters cemented in place across from treatment interval
– Fracture height deduced from inversion of tilt data using 3D Finite Element model
– Very good agreement between bulk of microseismic data and tilt results
– Several microseismic outliers
Linear gel minifracs– 2 identical injections– 400 bbl– 22 bpm
Inverted tilt fracture height
Microseismic depth histogram
13© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Microseismic Mapping Results
Well 2H (completed first)Well 1H (completed next)
N45°E to N55°E, Xf= 600 to 1,000 ft (most events <500 ft)
hf=250 – 480 ft; wnf=370 -920 ftPressure interference for all fractures
Well 1H Fracture Stimulation
Time (min)
Surf Press [Csg] (psi) Bottomhole Press (psi)Slurry Flow Rate (bpm) Slurry Density (lbm/gal)
60293 60812 61330 61849 62367 62885 0
1700
3400
5100
6800
8500
3900
4100
4300
4500
4700
4900
0
40
80
120
160
200
0.0
2.0
4.0
6.0
8.0
10.0
53 71 174 181 318 46 ?Pressure rise
14© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Production Interference
Core Area Barnett Shale
Shut-ins cause corresponding rate increase in other well
15© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Shallow Microseismicity: What is it?
Bakken example Dohmen et al.SPE 166274
Side view of zones of microseismicityin two wells in the Bakken
Large amount of activity 800 to 1,000 ft above the Bakken
16© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Downhole Tiltmeter Assessment of Height Growth
Hybrid tools with both microseismic and tiltmetermonitoring provide additional information– Where actual deformation is
occurring– Likelihood of hydraulic
connectivity
Cases:– Heights: 50, 100, 200 ft– Net pressure: 1000 psi– Modulus: 5e+6 psi– Length > monitoring distance
-500-400-300-200-100
0100200300400500
-200 -100 0 100 200
Dept
h fro
m ce
nter
of fr
actu
re, f
t
Tilt, microradians
H=50 ftH=100 ftH=200 ft
-500-400-300-200-100
0100200300400500
-75 -25 25 75
Dept
h fro
m ce
nter
of f
ract
ur, f
t
Tilt, microradians
Two FracturesH=100 ft
17© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Integrating Microseismic and Fiber Optics Microseismicity
– Uncertainty of fracture initiation, entrance conditions & number of fractures
Fiber optics provides near-wellbore information– Diversion– Control DTS DAS
18© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Source Mechanisms Analysis of waveforms to determine
“fault” characteristics Requires:
– 2 wells– High quality data
• Low noise• Good coupling
– Accurate locations– Accurate velocity models Provides:
– “Fault-plane” orientations– Slippage direction– Strength of the microseism– Volumetric behavior Major issue:
– Uncertainty• Everything looks volumetric
n
u
Some claim it can show fractures closing!Impossible to create a closure microseism in a fluid filled fracture (try clapping underwater)
It should tell us something about the reservoir
19© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Hydraulic Fracture Energy Budget Total energy of fracturing operation
– ~ 50 gJ Strain energy of hydraulic fractures
– Single fracture ~ 6 gJ (12%)– Three fractures ~ 18 gJ (36%) Microseismic energy
– Typically ~ 10 – 100 kJ– One part in 106 to 109
Quasi-static process
Typical Marcellus treatmentH = 250 ftL = 700 ftP = 800 psiwavg = 0.015 inmin = 6,000 psiQ = 90 bpm for 90 min
A DFN built on microseismic data alone is missing >99.9999% of the deformation
20© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
0
2000
4000
6000
8000
10000
12000
140001 1001 2001 3001 4001 5001 6001
Dept
h, ft
Fracture stages
Mapped Microseismic Height: North American Shales Top: shallowest microseism; Bottom: deepest microseism
SPE 145949
Typical aquifer depths
Fracture tops
Fracture bottoms
Average perforation depth
BarnettMarcellusEagle FordHaynesvilleWoodfordMuskwa
21© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Summary of Observed Seismicity – Shales Microseismic
monitoring provides detailed data on potential for seismic events– Number of monitored
fractures approaching 50,000
0
50
100
150
200
250
300
350
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1
Freq
uenc
y
Moment Magnitude
MuskwaWoodfordHaynesvilleEagle FordMarcellusBarnett
0
50
100
150
200
250
300
350
-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3
Freq
uenc
y
Moment Magnitude
MuskwaWoodfordHaynesvilleEagle FordMarcellusBarnett
Largest microseism observed
Typical size of seismic event that can just be felt
Similar to Richter magnitude
22© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
Summary
Microseismicity provides valuable information about fracture behavior and completion effectivenessMicroseismic monitoring does have issues that need to
be considered when interpreting results The interpretation of microseismicity benefits when
integrated with other diagnostics. Care needs to be taken when attempting to use source
mechanism information
23© 2011 HALLIBURTON. ALL RIGHTS RESERVED.
NASA photo:
Shiprock
Shiprock dike, Louis Maher photograph
Questions?
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