none 10.1190/1.1567214 Society of Exploration Geophysicists Society of Exploration Geophysicists 186 7640997 5981 2025121111433744300 10.1190 2025-12-11T16:43:50Z 2003-04-21T13:46:08Z 332 Geophysics 1942-2156 0016-8033 2003 01 01 2003 68 2 James T. Rutledge ∗ Los Alamos National Laboratory, Geophysics Group, Seismic Research Center, MS D443, Los Alamos, New Mexico 87545. E-mail: jrutledge@lanl.gov. W. Scott Phillips ∗ Los Alamos National Laboratory, Geophysics Group, Seismic Research Center, MS D443, Los Alamos, New Mexico 87545. E-mail: jrutledge@lanl.gov. Abstract We produced a high-resolution microseismic image of a hydraulic fracture stimulation in the Carthage Cotton Valley gas field of east Texas. We improved the precision of microseismic event locations four-fold over initial locations by manually repicking the traveltimes in a spatial sequence, allowing us to visually correlate waveforms of adjacent sources. The new locations show vertical containment within individual, targeted sands, suggesting little or no hydraulic communication between the discrete perforation intervals simultaneously treated within an 80-m section. Treatment (i.e., fracture-zone) lengths inferred from event locations are about 200 m greater at the shallow perforation intervals than at the deeper intervals. The highest quality locations indicate fracture-zone widths as narrow as 6 m. Similarity of adjacent-source waveforms, along with systematic changes of phase amplitude ratios and polarities, indicate fairly uniform source mechanisms (fracture plane orientation and sense of slip) over the treatment length. Composite focal mechanisms indicate both left- and right-lateral strike-slip faulting along near-vertical fractures that strike subparallel to maximum horizontal stress. The focal mechanisms and event locations are consistent with activation of the reservoir's prevalent natural fractures, fractures that are isolated within individual sands and trend subparallel to the expected hydraulic fracture orientation (maximum horizontal stress direction). Shear activation of these fractures indicates a stronger correlation of induced seismicity with low-impedance flow paths than is normally found or assumed during injection stimulation. 2003 01 01 2003 01 01 2003 441 452 10.1190/1.1567214 https://pubs.geoscienceworld.org/geophysics/article/68/2/441/73769/Hydraulic-stimulation-of-natural-fractures-as https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/68/2/441/3192437/gsgpy_68_2_441.pdf https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/68/2/441/3192437/gsgpy_68_2_441.pdf http://geophysics.geoscienceworld.org/cgi/doi/10.1190/1.1567214 Quantitative seismology, theory and methods Aki 1980 Soc. Petro. Eng. J. Albright 22 523 1982 10.2118/9509-PA Acoustic emissions as a tool for hydraulic fracture location: Experience at the Fenton Hill Hot Dry Rock site Propagation of a hydraulic fracture into a remote observation wellbore Branagan 1997 J. Geophys. Res. Brown 103 2489 1998 10.1029/97JB03113 Fluid permeability of deformable fracture networks Quaternary faulting in east Texas Collins 1980 10.23867/GC8001D Geophys. J. Internat. Cornet 140 465 2000 10.1046/j.1365-246x.2000.00018.x Comment on “Large-scale in situ permeability tensor of rocks from induced microseismicity” by S.A. Shapiro, P. Audigane and J.-J. Royer Pure Appl. Geophys. Cornet 145 677 1995 10.1007/BF00879595 Analysis of induced seismicity for stress field determination and pore pressure mapping Identification of MHF fracture planes and flow paths: A correlation of well log data with patterns in locations of induced seismicity Dreesen 339 1987 Geological analysis of the Travis Peak formation and Cotton Valley sandstone Dutton 1991 Geothermics Evans 28 455 1999 10.1016/S0375-6505(99)00023-1 Stress and rock mechanics issues of relevance to HDR/HWR engineered geothermal systems: Review of developments during the past 15 years Hydrologically-significant structures imaged by induced microseismicity in a 3-km deep well in granite at Soultz Evans 2001 Internat. J. Rock Mech. Min Sci. Geomech. Abstr. Fehler 26 211 1989 10.1016/0148-9062(89)91971-2 Stress control of seismicity patterns observed during hydraulic fracturing experiments at the Fenton Hill Hot Dry Rock geothermal site, New Mexico The Leading Edge Fehler 20 324 2001 10.1190/1.1438942 More than cloud: New techniques for characterizing reservoir structures using induced seismicity Proc. IEEE Flinn 53 1725 1965 10.1109/PROC.1965.4462 Signal analysis using rectilinearity and direction of particle motion Comput. Geosci. Frohlich 5 387 1979 10.1016/0098-3004(79)90034-7 An efficient method for joint hypocenter determination for large groups of earthquakes Induced seismicity analysis for structure identification and stress field determination Gaucher 1998 10.2118/47324-MS Characterization of an induced hydraulic fracture completion in a naturally fractured Antrim shale reservoir Hopkins 1998 10.2118/51068-MS Geophys. Res. Lett. House 14 919 1987 10.1029/GL014i009p00919 Locating microearthquakes induced by hydraulic fracturing in crystalline rock Imaging induced microseismicity during the 1993 injection test at Soultz-sous-Forêts, France Jones 2665 1995 J. Geophys. Res. Jones 102 8245 1997 10.1029/96JB03739 A method for determining significant structures in a cloud of earthquakes Monitoring and management of fractured reservoirs using induced microearthquakes activity Jupe 1998 10.2118/47315-MS Tectonophysics Laubach 156 37 1988 10.1016/0040-1951(88)90281-8 Subsurface fractures and their relationship to stress history in east Texas basin sandstone Coring-induced fractures Laubach 1988 J. Petr. Sci. Eng. Mahrer 24 13 1999 10.1016/S0920-4105(99)00020-0 A review and perspective on far-field hydraulic fracture geometry studies Waterfracs—Results from 50 Cotton Valley wells Mayerhofer 1998 10.2118/49104-MS Proppants? We don't need no proppants Mayerhofer 1997 East Texas hydraulic fracture imaging project Mayerhofer 2000 A tight gas field study McCain 1993 Geophysics Moriya 59 36 1994 10.1190/1.1443532 Precise source location of AE doublets by spectral matrix analysis of triaxial hodogram Pure Appl. Geophys. Moriya 159 517 2002 10.1007/PL00001263 Detailed fracture system of the Soultz-sous-Forêts HDR field evaluated using microseismic multiplet analysis J. Geophys. Res. Pearson 86 7855 1981 10.1029/JB086iB09p07855 The relationship between microseismicity and high pore pressures during hydraulic stimulation experiments in low permeability granitic rocks Observations from the east Texas seismic network (June 1981-August 1982) Pennington 1984 10.23867/GC8403D Bull Seis. Soc. Am. Phillips 90 212 2000 10.1785/0119990047 Precise microearthquake locations and fluid flow in the geothermal reservoir at Soultz-sous-Forêts, France J. Geophys. Res. Phillips 102 11745 1997 10.1029/97JB00762 Detailed joint structure in a geothermal reservoir from studies of induced micro-earthquake clusters Tectonophysics Phillips 289 153 1998 10.1016/S0040-1951(97)00313-2 Induced microearthquake patterns and oil-producing fracture systems in the Austin Chalk FPFIT, FPPLOT and FPPAGE: Fortran computer programs for calculating and displaying earthquake fault-plane solutions Reasenberg 1985 Internat. J. Rock Mech. and Min. Sci. and Geomech. Abstr. Roff 33 627 1996 Joint structures determined by clustering microearthquakes using waveform amplitude ratios Pure Appl. Geophys. Rowe 159 563 2002 10.1007/PL00001265 Using automated, high-precision repicking to improve delineation of microseismic structures at the Soultz geothermal reservoir Nature Rubin 400 635 1999 10.1038/23196 Streaks of microearthquakes along creeping faults Analyses of the Cotton Valley microseismic data for asymmetric fracture growth Rutledge 1998 A comparison of microseismicity induced by gel-proppant- and water-injected hydraulic fractures, Carthage Cotton Valley gas field, east Texas Rutledge 2393 2002 Tectonophysics Rutledge 289 129 1998 10.1016/S0040-1951(97)00312-0 Reservoir characterization using oil-production-induced microseismicity, Clinton County, Kentucky Cotton Valley imaging project, phase IV, completion of microseismic mapping of the phase I and II hydraulic fractures, wells CGU21-10 and CGU21-09 Rutledge 1999 Tectonophysics Segall 289 117 1998 10.1016/S0040-1951(97)00311-9 A note on induced stress changes in hydrocarbon and geothermal reservoirs Proc. Roy. Soc. Sneddon 187 229 1946 The distribution of stress in the neighborhood of a crack in an elastic solid Earthquake Notes Snoke 55 15 1984 A program for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data Eng. Geology Tezuka 56 47 2000 10.1016/S0013-7952(99)00133-7 Stress estimated using microseismic clusters and its relationship to fracture systems of the Hijiori hot dry rock reservoir Using microseismicity to map Cotton Valley hydraulic fractures Urbancic 1444 2000 Determining hydraulic fracture behavior using microseismicity Urbancic 991 1999 Cotton Valley hydraulic fracture imaging project :Feasibility of determining fracture behavior using microseismic event locations and source parameters Urbancic 964 1998 Proc. IEEE Vaidyanathan 78 56 1990 10.1109/5.52200 Multirate digital filters, filter banks, polyphase networks, and applications: A tutorial Cotton Valley hydraulic fracture imaging project Walker 1997 10.2118/38577-MS J. Petro. Tech. Warpinski 39 209 1987 10.2118/13224-PA Influence of geologic discontinuities on hydraulic fracture propagation Microseismic mapping of hydraulic fractures using multi-level wireline receivers Warpinski 1995 10.2118/30507-MS Cotton Valley production stimulation hydrofracture microseismic monitoring & imaging, data collection and analysis report Withers 1997 Annales Geophysicae Zoback 2 689 1984 Friction, faulting and in situ stress