An improved method for hydrofracture-induced microseismic event detection and phase picking

Song, Fei; Küleli, H. Sadi; Toksöz, M. Nafi; Ay, Erkan; Zhang, Haijiang

doi:10.1190/1.3484716

Cited by 95 publications

(41 citation statements)

References 24 publications

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“…We picked arrivals for 32,078 microearthquakes using a short-term average to long-term average algorithm, and then refined these picks using spectral methods [e.g. Song et al, 2010]. Linear clock drift corrections were applied to each station, and these corrections were further refined to account for non-linear clock drift by cross-correlating long-wavelength (> 500 m) microseism signals [Webb, 1992;Webb and Crawford, 1999] propagating across the small-aperture sub-network.…”

Section: Discussionmentioning

confidence: 99%

Deep explosive volcanism on the Gakkel Ridge and seismological constraints on shallow recharge at TAG active mound

Pontbriand¹

2013

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Seafloor digital imagery and bathymetric data are used to evaluate the volcanic characteristics of the 85°E segment of the ultraslow spreading Gakkel Ridge (9 mm yr -1 ). Imagery reveals that ridges and volcanic cones in the axial valley are covered by numerous, small-volume lava flows, including a few flows fresh enough to have potentially erupted during the 1999 seismic swarm at the site. The morphology and distribution of volcaniclastic deposits observed on the seafloor at depths of ~3800 m, greater than the critical point for steam generation, are consistent with having formed by explosive discharge of magma and CO 2 from source vents.Microearthquakes recorded on a 200 m aperture seismometer network deployed on the Trans-Atlantic Geotraverse active mound, a seafloor massive sulfide on the Mid-Atlantic Ridge at 26°N, are used to image subsurface processes at the hydrothermal system. Over nine-months, 32,078 local microearthquakes (M L = -1) with single-phase arrivals cluster on the southwest flank of the deposit at depths <125 m. Microearthquakes characteristics are consistent with reaction-driven cracking driven by anhydrite deposition in the shallow secondary circulation system. Exit fluid temperatures recorded at diffuse vents on the mound during the microearthquake study are used to explore linkages between seismicity and venting. AcknowledgmentsI owe my deepest gratitude to my advisers, Rob Sohn and Adam Soule, for their invaluable guidance, continual patience and support throughout the course of my graduate work. They contributed enormous energy and enthusiasm to my research and taught me how to question, pursue knowledge, and take chances. I would like to express great appreciation to all the members of my thesis committee for their insights during the preparation of this thesis: Andy Solow, Jeff McGuire, Nafi Toksöz, and Meg Tivey. I would especially like to thank Andy Solow for guidance on statistical methods; Jeff McGuire for sharing his expertise in seismology and for the field experience of working on an active source survey; Nafi Toksöz and the MIT Earth Resources Laboratory, including Fuxian Song and Junlun Li, for sharing their work on small-scale seismics; and Meg Tivey for her knowledge of the geochemical processes and structure of the TAG active mound. I would also like to thank my Thesis Defense Chair, Susan Humphris, for her feedback and patient explanations of Gakkel Ridge geochemistry. It is an honor for me to benefit from the expertise of these scientists. Assistance provided by the WHOI Academic Programs Office, especially Julia Westwater, is greatly appreciated. I would like to extend thanks to Jim Yoder for allowing me a voice about the direction of the program, and the JCMG&G, especially Rob Evans, for encouraging my progress. I wish to acknowledge my professors, especially Ralph Stephen, Jack Whitehead, and Lauren Mullineaux, for their engaging teaching. Thanks to my administrator, Kelly Servant, for her encouragement, and to my fellow students in the Joint Program and WHO...

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Section: Discussionmentioning

confidence: 99%

Deep explosive volcanism on the Gakkel Ridge and seismological constraints on shallow recharge at TAG active mound

Pontbriand¹

2013

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“…This records the physical phenomena caused by fracture propagation acting like a microearthquake [52]. As the fracture opens it propagates a primary (or compression) wave and a shearing wave (Pand S-waves, respectively) through the surrounding medium.…”

Section: Numerical Illustration: Electromagnetic Excitation Of Non-brmentioning

confidence: 99%

Electromagnetic excitation of particle suspensions in hydraulic fractures using a coupled lattice Boltzmann-discrete element model

et al. 2015

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This paper describes the development of a computational framework that can be used to describe the electromagnetic excitation of rigid, spherical particles in suspension. In this model the mechanical interaction and kinematic behaviour of the particles is modelled using the discrete element method, while the surrounding fluid mechanics is modelled using the lattice Boltzmann method. Electromagnetic effects are applied to the particles as an additional set of discrete element forces, and the implementation of these effects was validated by comparison to the theoretical equations of point charges for Coulomb's law and the Lorentz force equation. Oscillating single and multiple particle tests are used to investigate the sensitivity of particle excitation to variations in particle charge, field strength, and frequency. The further capabilities of the model are then demonstrated by a numerical illustration, in which a hydraulic fracture fluid is excited and monitored within a hydraulic fracture. This modelling explores the feasibility of using particle vibrations within the fracture fluid to aid in the monitoring of fracture propagation in unconventional gas reservoirs.

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“…In actual situations, seismic signals recorded by geophones are usually contaminated by noise, which may cause picking errors (Rodriguez et al 2012;Song et al 2010;Tan et al 2014). Compared with borehole observations, the picking errors of P-wave arrivals are relatively large at the surface.…”

Section: The Sensitivity To Picking Errorsmentioning

confidence: 99%

Velocity calibration for microseismic event location using surface data

et al. 2016

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Because surface-based monitoring of hydraulic fracturing is not restricted by borehole geometry or the difficulties in maintaining subsurface equipment, it is becoming an increasingly common part of microseismic monitoring. The ability to determine an accurate velocity model for the monitored area directly affects the accuracy of microseismic event locations. However, velocity model calibration for location with surface instruments is difficult for several reasons: well log measurements are often inaccurate or incomplete, yielding intractable models; origin times of perforation shots are not always accurate; and the non-uniqueness of velocity models obtained by inversion becomes especially problematic when only perforation shots are used. In this paper, we propose a new approach to overcome these limitations. We establish an initial velocity model from well logging data, and then use the root mean square (RMS) error of double-difference arrival times as a proxy measure for the misfit between the well log velocity model and the true velocity structure of the medium. Double-difference RMS errors are reduced by using a very fast simulated annealing for model perturbance, and a sample set of double-difference RMS errors is then selected to determine an empirical threshold. This threshold value is set near the minimum RMS of the selected samples, and an appropriate number of travel times within the threshold range are chosen. The corresponding velocity models are then used to relocate the perforation-shot. We use the velocity model with the smallest relative location errors as the basis for microseismic location. Numerical analysis with exact input velocity models shows that although large differences exist between the calculated and true velocity models, perforation shots can still be located to their actual positions with the proposed technique; the location inaccuracy of the perforation is \2 m. Further tests on field data demonstrate the validity of this technique.

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An improved method for hydrofracture-induced microseismic event detection and phase picking

Cited by 95 publications

References 24 publications

Deep explosive volcanism on the Gakkel Ridge and seismological constraints on shallow recharge at TAG active mound

Deep explosive volcanism on the Gakkel Ridge and seismological constraints on shallow recharge at TAG active mound

Electromagnetic excitation of particle suspensions in hydraulic fractures using a coupled lattice Boltzmann-discrete element model

Velocity calibration for microseismic event location using surface data

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