Dipole shear anisotropy logging

Esmersoy, Cengiz; Koster, Klaas; Williams, Marty zz; Boyd, Austin; Kane, M.

doi:10.1190/1.1822720

Cited by 65 publications

(30 citation statements)

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“…Flexural waves from each source are recorded along two perpendicularly orientated receiver arrays, resulting in four‐component (4C) recordings. The processing method we used is similar to the method presented by Esmersoy et al . (1994).…”

Section: Dsi Data Processingmentioning

confidence: 99%

A shear experiment over the Natih field in Oman: pilot seismic and borehole data

Hake¹,

Gevers²,

Kolk

et al. 1998

Geophysical Prospecting

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An experimental multicomponent three‐dimensional (3D) seismic survey has been carried out over the Natih field in Oman. This paper describes the small‐scale two‐dimensional experiment carried out beforehand, and how the results obtained from this pilot were used to assess the feasibility of a nine‐component three‐dimensional (9C3D) operation as well as to determine the field parameters for the field‐scale 3D survey. It also describes the two VSPs and a wireline shear log, acquired in conjunction with the pilot experiment, and the importance of such borehole data for establishing the correct time‐to‐depth relationship for the seismic data and for providing an independent check on the seismic interpretation. The observation of cusps in the offset VSP indicated the strong anisotropy of the Fiqa shales overlying the Natih reservoir.

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Section: Dsi Data Processingmentioning

confidence: 99%

A shear experiment over the Natih field in Oman: pilot seismic and borehole data

Hake¹,

Gevers²,

Kolk

et al. 1998

Geophysical Prospecting

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“…The same equations are also given by Sinha et al (1994) andEsmersoy et al (1994). These are our forward decomposition formulas for the acoustic dipole log.…”

Section: Forward Decomposition Of the Dipole Logmentioning

confidence: 78%

“…Most of our knowledge comes from the perturbation solution. On the other hand, field data observations in the anisotropic formation are available, e.g., borehole waves generated from a vertical seismic profile (Barton and Zoback, 1988; Leveille and Seriff, 1989) and borehole dipole logging (Esmersoy et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Decomposition and particle motion of acoustic dipole log in anisotropic formation

Cheng¹,

Cheng²

1995

SEG Technical Program Expanded Abstracts 1995

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For linear wave propagation in anisotropic media, the principle of superposition still holds. The decomposition of the acoustic dipole log is based on this principle. In the forward decomposition inline and crossline acoustic dipole logs at any azimuthal angle the projection of measurements is along the principal direction of the formation. In the inverse decomposition the measurements along the principal direction can be constructed from the orthogonal pair of inline and crossline acoustic dipole log. The analytic formulas for both forward and inverse decompositions of the dipole laaa ssssaog are derived in this paper. The inverse decomposition formula is the solution in the least-square sense. Numerical examples are demonstrated for the acoustic dipole log decomposition in isotropic and anisotropic formations. The synthetic dipole log is calculated by the 3-D finite difference method. The numerical examples also show that the inverse decomposition formula works very well with noisy data. This inverse decomposition formula will be useful to process the field acoustic logging data in anisotropic formations. It can provide the direction of the formation anisotropy as well as the degree of anisotropy. Because acoustic dipole logging is in the near field distance, the particle motion is complicated. The particle motion is linearly polarized only in the principle direction. The initial particle motion with a dipole source at an arbitrary azimuthal angle tends to point in the fast shear wave direction. However, it will be difficult to use this information to find a stable estimation of a fast shear wave direction. 2-1 Cheng and Cheng

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“…The resulting waveforms corresponding to the fast-and slow-shear orientations are then processed by use of the semblance method to obtain the fast-and slow-shear slownesses. 11,12 In Fig. 1, we show an example of a typical anisotropy log from the Burgos basin.…”

Section: Shear Anisotropy From Crossed-dipole Logging Toolsmentioning

confidence: 99%

Using Shear-Wave Anisotropy To Optimize Reservoir Drainage and Improve Production in Low-Permeability Formations in the North of Mexico

Franco¹,

Torre²,

Ortiz³

et al. 2005

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractShear waves propagate through rock with different velocities in different directions. This phenomenon is called acoustic anisotropy, and it is caused by the anisotropic nature of the rock's elastic properties. All sedimentary rocks exhibit some degree of acoustic anisotropy related to aligned fractures, layering, or stress imbalance. Until recently, wireline sonic tools were able to measure the anisotropy magnitude and orientation reliably only if the velocity anisotropy was greater than 5%. In this paper, we will discuss the field test results from multiple wells of a new sonic tool that is able to measure anisotropy as low as 1%. We will also comment on how to identify the cause of the anisotropy and its applications. Because we can measure the acoustic anisotropy with this new tool-even if it is very low-and relate it to the earth-stress direction, we are able to provide reservoir engineers with valuable information to optimize the field development and improve well production.The tests were conducted in several Pemex development wells in northern Mexico, mostly in the Burgos basin. The target formations were tight gas sands. The sands have very low permeability and must be stimulated to produce hydrocarbons in commercial quantities. These hydraulically fractured vertical wells have elliptical drainage patterns, and optimum reservoir drainage depends on the correct well placement to avoid creating interference between wells (overlapping drainage areas) or leaving areas untouched (drainage gaps). Since hydraulic fractures open in a plane perpendicular to the minimum stress, determining stress direction is crucial to the placement of new wells. Also, it can help to look for in-field drilling opportunities in brown fields where early drilling strategies did not consider the stress orientation when selecting well locations. In addition, by knowing the stress-field state, it is possible to apply oriented perforating techniques to maximize the results of the fracture treatments.

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Dipole shear anisotropy logging

Cited by 65 publications

References 0 publications

A shear experiment over the Natih field in Oman: pilot seismic and borehole data

A shear experiment over the Natih field in Oman: pilot seismic and borehole data

Decomposition and particle motion of acoustic dipole log in anisotropic formation

Using Shear-Wave Anisotropy To Optimize Reservoir Drainage and Improve Production in Low-Permeability Formations in the North of Mexico

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