Fracture Geometry from Microseismic Norm Warpinski Pinnacle A Halliburton Service
Hydraulic Fracturing: Models Versus Reality Conceptually, fracturing is a simple process Elastic behavior Planar fractures Conservation of mass & momentum Reality is more interesting Complex fracture Crosslinked gel 3 Stages of colored sand Black, red, then blue Substantial mixing and layering of sand stages
Hydraulic Fracturing in the Barnett Initial waterfracs in vertical wells in the Barnett resulted in a series of bashed wells Prior to microseismic monitoring, the actual mechanism was unclear Bashed offset wells
Microseismic Monitoring An Engineering Tool Microseismic i i monitoring i is a valuable tool for optimizing Well layout Well spacing Stage lengths Perf clusters and/or valves & packers Stimulation design Complexity Calibrated fracture model Focus now: Providing the most accurate event locations and maximum viewability for correct decisions Engineering i applications using microseismicity Is it possible to extract other information from the microseismicity SPE 145463, Mayerhofer et al., Seneca Res. SKTL Shale Marcellus Onondaga
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 P-S Separation P P Moveout S S Moveout State-of-the-art microseismic receiver arrays Calibrated Array apertures Fiber-optic i wirelines Velocity of 200 1000 m Model Vertical Up V Clamp Arm In Back H2 H1 Tri-Axial Sensors (Geophones) Wall-lock clamped tools 5
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 No orth (ft) 600 450 300 150 N74W MWX-3 MWX2 MONITOR AT INTERSECTION Well 0-450 -300-150 0 150 300 West-East t (ft) Primary validation experiments: M-Site microseismic, tiltmeters, intersection wells, tracers, pressure interference Mounds Drill Cuttings microseismic, tiltmeters, intersection wells, tracers Mitchell Barnett microseismic, surface & downhole tiltmeters, offset wells INTERSECTION WELL
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? Full spectrum of behavior South-Nort th (m) 1000 800 600 400 200 0 Barnett Mesaverde -200-600 -500-400 -300-200 -100 0 100 200 West-East t( (m)
Microseismic Mapping Results N45 E to N55 E X f = 600 to 1,000 ft (most events <500 ft) h f =250 480 ft Pressure interference for all fractures SKTL Shale Marcellus Well 1H Fracture Stimulation Slurry Flow Rate (bpm) Slurry Density (lbm/gal) 200 Surf Press [Csg] (psi) Bottomhole Press (psi) 10.0 8500 4900 53 71 174 181 318 46? Pressure rise 160 6800 8.0 4700 BH Pressure Gauge data in Well 2H 120 5100 6.0 4500 80 3400 4.0 4300 Well 2H (completed first) Well 1H (completed next) 40 1700 0 0.0 0 60293 60812 61330 61849 62367 62885 3900 Time (min) SPE 145463, Mayerhofer et al., Seneca Res. 2.0 4100
Production Interference Core Area Barnett Shale Shut-ins cause corresponding rate increase in other well
Microseismic Monitoring: Unconventional Reservoirs Multi-stage lateral Packer Completion Excellent geometry values for modeling Added value by integrating with other diagnostic technologies DFIT s Calibrated model SPE 148780, Canadian sedimentary basin example
Modeling example Calibrated Model and Proppant Transport Modeled fracture geometry matched to the measured microseismic geometry Proppant transport models calculated from the given data From this data, long term production estimates can be made
Cardium Example: Treatment Well Relatively planar fractures Mostly consistent lengths and height growth Easily amenable to modeling Observation Well ~70 m 3 Nitrified Gel ~3 m 3 / min ~20 tonne sand
Horn River example: variable complexity (faulting) C-99-H: 6 fracs; 2.9 MM lb sand; 3.7 MM gal water Muskwa
Example Maps: Height Growth Variable containment t in shales Containment (e.g., Eagle Ford & Barnett) Bounded by carbonates Upward growth (e.g., Marcellus & Haynesville) Continuous shale SPE 125079 GMX Resources 600 ft Haynesville Example Austin Chalk Eagle Ford Example Marcellus Example Eagle Ford 900 ft Buda SPE 148642, Magnum Hunter Resources, Inc. SPE 131783,Curry et al, 2010
Microseismic Source Analysis Microseismic mapping is based on the distribution of microseismic events Envelope surrounding fracture Waveforms clearly contain information about the fault planes Radiation pattern is a function of the orientation ti & direction of slippage Some useful information should be extractable from the waveforms Magnitude, size, stress drop Fault mechanism Can we use this information to further understand the hydraulic fracture? Tied directly into the hydraulic fracturing geomechanics
Microseismic Moment & Magnitude Analysis Analyses Moment (strength) M o = G A d G shear modulus A slippage area d distance moved cm-s) Displacemen nt Spectrum ( 1.0E-09 1.0E-10 Magnitude (log scale) 1.0E-11 M w = 2 / 3 { log 10 [ M o ] const } Spectral analysis for moment and size Brune approach 1.0E-12 1.0E-13 f c Ω Ο 10 100 1000 10000 Frequency (Hz) M o = 3 s 4πρV F c RΩ o r o = KcV 2π f s c
Microseismic Viewing Capabilities How Far Can We See? 0 Faults -0.5 Muskwa Faults: >2,000 m Marcellus Barnett Woodford Mo oment Magniitude -1 1 EagleFord Montney -1.5 Shales: >1,200 m -2 2-2.5-3 3-3.5 Some Variabilityy In Viewing Limit -4 4-4.5 0 400 800 Distance (m) 1200 1600
Energy & Volume: Microseisms Versus Fracture Microseismic energy Magnitude -2 -> ~60 J Magnitude -1 -> ~2000 J 500 microseisms in a typical fracture treatment Magnitude -2: ~30 kj Magnitude -1: ~1000 kj Hydraulic fracture Based on horsepower 10 7 10 9 kj Based on fracture work 10 6 10 8 kj Microseismic volume (all tensile) Magnitude -2 -> 0.000084 m 3 Magnitude -1 -> 0.042042 m 3 500 microseisms in a typical fracture treatment Magnitude -2: 0.0335 m 3 Magnitude -1: 1.33 m 3 Hydraulic fracture Volume injected 1500 m 3 An analysis of source mechanisms cannot provide information about the hydraulic fracture
Mapped Microseismic Height: North American Shales Top: shallowest microseism; Bottom: deepest microseism Top: shallowest microseism; Bottom: deepest microseism 0 500 1000 Typical aquifer depths SPE 145949 Depth, m 1500 2000 2500 3000 Fracture tops Fracture bottoms 3500 4000 4500 Average perforation depth 1 1001 2001 3001 4001 5001 6001 Fracture stages
Environmental Questions: Microseismicity in Shale Basins Thousands of fractures monitored No significant seismic activity Relaxed basins Minimal tectonics Depth, m 500 1000 1500 2000 2500 3000 3500 4000 Barnett Marcellus Eagle Ford Woodford Haynesville Horn River SPE 151597 4500-3.5-3.0-2.5-2.0-1.5-1.0-0.5 0.0 0.5 1.0 Moment magnitude
Conclusions Fracture diagnostics, and microseismic mapping in particular, have provided important understanding of hydraulic fracturing Fracture length Fracture complexity (stress bias and natural fractures) Fracture height growth Effects of geohazards Interactions between wells and stage Completion effects (plug and perf, packers & sleeves, etc.) Fracture diagnostics provide input for calibrated models and improved fracture design and analysis Geologic complexity
Questions?