An integrated three‐component approach to fracture detection

Martin, Mylène; O'Rourke, Tom

doi:10.1190/1.1893146

Cited by 6 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this case will be self-evident, since the mismatched receiver will record only noise. This method [single-source multiple receivers, equations (lo)] was used by Martin et al (1986). By use of equations (7) or equations (10) on each set of traces along a survey line, the partial redundancy of conventionally acquired surface reflection data is used to overcome the problems (Crampin, 1984b(Crampin, , 1985a which are potentially associated with surface data.…”

Section: Determination Of the Principal Time Seriesmentioning

confidence: 99%

“…. "-A series of papers presented at the 1986 SEG Convention (Thomsen, 1986b;Rai and Hanson, 1986;Lynn and Thomsen, 1986;Alford, 1986b;Willis et al, 1986;and Martin et al, 1986;cf., also Alford, 1986a, andAlford et al, 1986) provided arguments and data to show that these difficulties at the free surface may be overcome by appropriate data acquisition and analysis techniques. Taken as a group, these papers assert that the effects of azimuthal anisotropy on surface shear-wave (Swave) data are profound and that the implications of the effects are far-reaching.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reflection seismology over azimuthally anisotropic media

Thomsen¹

1988

GEOPHYSICS

236

137

View full text Add to dashboard Cite

Recent surveys have shown that azimuthal anisotropy (due most plausibly to aligned fractures) has an important effect on seismic shear waves. Previous work had discussed these effects on VSP data; the same effects are seen in surface recording of reflections at small to moderate angles of incidence. The anisotropic effects one different polarization components of vertically traveling shear waves permit the recognition and estimation of very small degrees of azimuthal anisotropy (of order 2 1 percent), as in an interferometer. Anisotropic effects on traveltime yield estimates of anisotropy which are averages over large depth intervals. Often, raw field data must be corrected for these effects before the reflectors may be imaged; two variations of a rotational algorithm to determine the "principal time series" are derived. Anisotropic effects on moveout lead to abnormal moveout unless the survey line is parallel to the fractures. Anisotropic effects on reflection amplitude permit the recognition and estimation of anisotropy (hence fracture intensity) differences at the reflecting horizon, i.e., with high vertical resolution,

show abstract

Section: Determination Of the Principal Time Seriesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reflection seismology over azimuthally anisotropic media

Thomsen¹

1988

GEOPHYSICS

236

137

View full text Add to dashboard Cite

show abstract

“…Observation and study of azimuthal anisotropy effects through S-wave analysis from seismic data, for both surface (Alford, 1986;Frasier & Winterstein, 1986;Lynn & Thomsen, 1986;Martin et al, 1986;Willis et al, 1986) and vertical seismic profiles (Winterstein et al, 2001;Gaiser, 2016) data have been well documented in the literature. The presence of azimuthal anisotropy causes 𝑆 1 and 𝑆 2 waves to propagate at different velocities.…”

Section: Introductionmentioning

confidence: 96%

Attenuating pseudo S‐wave splitting caused by vector infidelity

Bezerra

Gaiser

Simmons

2023

Geophysical Prospecting

View full text Add to dashboard Cite

Shear wave (S-wave) splitting analysis can provide knowledge about, among other properties, principal stress directions and fracture orientation. It is an essential step in multi-component, converted wave processing. Caution must be taken, however, when performing such analysis on ocean bottom cable seismic data, which is highly susceptible to different coupling of the two horizontal components with the seafloor. Receiver coupling correction methods attempt to balance the seismic response on all components and seek to minimize spurious resonance effects. We show on field data from an ocean bottom cable seismic dataset how these coupling effects that simulate S-wave splitting behaviour can be attenuated to significantly improve PS-wave stack images of the shallow seabed. Furthermore, corrected pre-stack data of all azimuths may reveal true splitting effects for stress and fracture information.

show abstract

Ray series modeling of seismic wave travel times and amplitudes in three‐dimensional heterogeneous anisotropic crystalline rock: Borehole vertical seismic profiling seismograms from the Mojave Desert, California

Li¹,

Leary²,

Aki³

1990

J. Geophys. Res.

View full text Add to dashboard Cite

A 600-m borehole vertical seismic profiling (VSP) survey conducted in crystalline rock in the Mojave Block stress province, southern California, yielded 100 oriented three-component seismograms from a fan-shooting geometry with radius of 100 m using both vertical and horizontal vibrators and a vertical impact source. The seismograms show up to 12 ms of shear wave splitting and 5% lateral velocity heterogeneity. First-and second-order ray tracing was used to model the travel times and amplitudes of P-, SV-and SH-waves in a three dimensional mildly heterogeneous medium with elastic anisotropy induced by aligned fractures. A least squares inverse procedure was used to improve model parameters determined by forward modeling; the final root mean square travel time residual was +_2 ms. For purposes of amplitude computation we assume that the wavelets observed in a VSP section derive from a smooth intermediate interface (base of weathering layer or sedimentary/basement interface) that is illuminated by a narrow range of ray angles originating at a point source on the surface. Source-derived amplitude complications are thus m'mimized. Our results strongly indicate a population of vertical cracks with an average crack density of 0.035 oriented in the N31.5øW direction. Such a fracture population is consistent with regional principal strain and stress determinations. Ray series geometric amplitudes were consistent with the observation that wave motion parallel to the aligned fractures decayed more slowly than wave motion transverse to the aligned fractures. We estimate that Q > 75-100; we were unable to measure a polarizationdependent Q. et al., 1970; Nur, 1971; Gupta, 1973; Anderson and Whitcomb, 1973; Kanamori and Hadley, 1975; Crampin, 1978]. Subsequently, the existence of fractures in basement rock was hypothesized by Smithson et at. [1980] and directly studied in the shallow basement by Green and Mair [1983]. Recently, shear wave splitting observations were obtained by threecomponent borehole vertical seismic profiling (VSP). Oriented three-component VSP data have provided a direct means of characterizing a fracture population in crustal rock [Martin et a/.,1986; Corrigan et a/.,1986; Leary et at., 1987; Majer et al., 1988; Li et al., 1988]. For instance, a crack density profile for oriented fractures was determined for a section of an active normal fault zone at Oroville, California [Leary et a/.,1987] and a Vsv/VSH ratio about 1.12 was estimated in the Geysers geothermal field, CA [Majer et al., 1988] from shear wave splitting observations in the plane of the local prevailing fracture set. The methods of three-component borehole seismic investigation of aligned fracture populations in crystalline rock are further explored in this paper. In contrast to the threecomponent borehole VSP work at Oroville [Leary et a/.,1987] Copyfight 1990 by the American Geophysical Union Paper number 89IB01170 0148-0227/90/89 IB-01170505.00 and at the Geysers geothermal field [Majer et al.,1988], where the principal fracture trends are ...

show abstract

An integrated three‐component approach to fracture detection

Cited by 6 publications

References 1 publication

Reflection seismology over azimuthally anisotropic media

Reflection seismology over azimuthally anisotropic media

Attenuating pseudo S‐wave splitting caused by vector infidelity

Ray series modeling of seismic wave travel times and amplitudes in three‐dimensional heterogeneous anisotropic crystalline rock: Borehole vertical seismic profiling seismograms from the Mojave Desert, California

Contact Info

Product

Resources

About