Synthetic full waveform acoustic logs in cased boreholes

Tubman, Kenneth M.; Cheng, C. H.; Toksoez, M. N.

doi:10.1190/1.1441720

Cited by 107 publications

(53 citation statements)

References 11 publications

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“…Recently published work has attempted to derive correlations to both porosity and clay content. Johnson and Pile (2006) report that in shaly formations the sonic porosity must be corrected for the presence of shale with the equation A number of investigators have described the mathematical treatment of wave propagation for boreholes of varying degrees of complexity (Biot 1952;White and Zechman 1968;Peterson 1974;Tsang and Radar 1979;Cheng and Toksoz 1981;Schoenberg et al 1981;Paillet and White 1982;Baker 1984;Tubman et al 1984;Timur and Toksoz 1985). Probably the most common choice of theory used in efforts to explain poroelastic data is Biot's theory.…”

Section: Physics Of Acoustic Measurementsmentioning

confidence: 99%

Evaluation of Non-Nuclear Techniques for Well Logging: Technology Evaluation

Bond¹,

Denslow²,

Griffin³

et al. 2010

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Sealed, chemical isotope radiation sources have a diverse range of industrial applications. There is concern that such sources currently used in the gas/oil well logging industry (e.g., americium-beryllium [AmBe], 252 Cf, 60 Co, and 137 Cs) can potentially be diverted and used in dirty bombs. Recent actions by the U.S. Department of Energy (DOE) have reduced the availability of these sources in the United States. Alternatives, both radiological and non-radiological methods, are actively being sought within the oilfield services community. The use of isotopic sources can potentially be further reduced, and source use reduction made more acceptable to the user community, if suitable non-nuclear or non-isotope-based well logging techniques can be developed. Data acquired with these non-nuclear techniques must be demonstrated to correlate with that acquired using isotope sources and historic records. To enable isotopic source reduction there is a need to assess technologies to determine (i) if it is technically feasible to replace isotopic sources with alternate sensing technologies and (ii) to provide independent technical data to guide DOE (and the Nuclear Regulatory Commission [NRC]) on issues relating to replacement and/or reduction of radioactive sources used in well logging.This report presents an initial review of the state-of-the-art nuclear and non-nuclear well logging methods and seeks to understand the technical and economic issues if AmBe, and potentially other isotope sources, are reduced or even eliminated in the oil-field services industry. Prior to considering alternative logging technologies, there is a definite need to open up discussions with industry regarding the feasibility and acceptability of source replacement. Industry views appear to range from those who see AmBe as vital and irreplaceable to those who believe that, with research and investment, it may be possible -to transition to electronic neutron sources and employ combinations of non-nuclear technologies to acquire the desired petro-physical parameters. In one sense, the simple answer to the question as to whether petro-physical parameters can be sensed with technologies other than AmBe is probably "Yes". The challenges come when attention turns to record interpretation. The many decades of existing records form a very valuable proprietary resource, and the interpretation of subtle features contained in these records are of significant value to the oil-gas exploration community to correctly characterize a well. The demonstration of equivalence and correspondence/correlation between established and any new sensing modality, and correlations with historic records is critical to ensuring accurate data interpretation. Establishing the technical basis for such a demonstration represents a significant effort.The focus of this study is the understanding of the technical obstacles that hinder the replacement of and the disadvantages from the loss of extensive interpretation experience based on data accumulated with AmBe. Enhanced ac...

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Section: Physics Of Acoustic Measurementsmentioning

confidence: 99%

Evaluation of Non-Nuclear Techniques for Well Logging: Technology Evaluation

Bond¹,

Denslow²,

Griffin³

et al. 2010

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“…The common occurrence of drilling induced formation damage or the presence of steel casing and associated cement justify the need to treat this more complicated geometry. The results of Tubman et al (1984) indicate that synthetic FWALs generated in cased or damaged boreholes can differ significantly from those 57 …”

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confidence: 94%

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ABSTRACTRecently published results (Tubman et al, 1984;Baker,. 1984) indicate that synthetic full waveform acoustic logs generated in cased or damaged boreholes differ significantly from those generated in an open hole with the same formation parameters.

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confidence: 99%

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Energy partitioning and attenuation of guided waves in a radially layered borehole

Burns¹,

Cheng²,

Toksöz³

1985

SEG Technical Program Expanded Abstracts

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Recently published results (Tubman et al., 1984;Baker,. 1984) indicate that synthetic full waveform acoustic logs generated in cased or damaged boreholes differ significantly from those generated in an open hole with the same formation parameters. In particular, the guided waves appear to be the most affected by such radial layering. In order to gain some understanding of these effects, the amplitude response and energy distribution of the pseudo-Rayleigh and Stoneley waves are studied for the cased and invaded borehole models. The expressions derived by Cheng et al. (1 982) are used to calculate partition coefficients (partial derivatives of phase velocity with respect to body wave velocities) for the guided wave modes. The attenuation of the guided wave can then be represented by the sum of the layer attenuation values weighted by their respective partition coefficients. The results indicate that the attenuation of the Stoneley wave is dominated by the fluid attenuation at all frequencies in fast formations, both in the open hole geometry and in the presence of casing or invaded zones. In a slow formation, the Stoneley wave attenuation becomes more sensitive to the shear wave attenuation of the formation at higher frequencies in both the open and cased hole situations. For the pseudoRayleigh wave, the introduction of casing reduces the effect of the fluid attenuation, while the presence of an invaded zone reduces the effect of the formation shear attenuation. Plots of the partition coefficients indicate that the casing and invasion layers are most important over a limited frequency range which is related to the thickness of the layer. Radial displacement curves illustrate the depth of penetration of the various frequency components of the pseudo-Rayleigh wave. INTROpUCTIONRecent interest in the field acquisition of Full Waveform Acoustic Logs (FWALs) has resulted in many studies of wave propagation in a cylindrical borehole (Cheng and Toksaz, 1981;Tsang and Rader, 1979;Paillet and White, 1982). The majority of these "have addressed the simple case of a homogeneous, Isotropic, infinite solid surrounding a fluid filled cylindrical borehole. Several recent papers (Tubman et aI., 1984;Baker, 1984;Chan and Tsang, 1983; Shoenberg et al., 1981) have addressed the more complex problem of solid radial layers surrounding a fluid filled borehole. The common occurrence of drilling induced formation damage or the presence of steel casing and associated cement justify the need to treat this more complicated geometry. The results of Tubman et al. (1984) indicate that synthetic FWALs generated in cased or damaged boreholes can differ significantly from those 57

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“…Cased borehole, mudcake or invaded zones can be modeled as a radially layered medium. Tubman et al (1984) used the Thomson-Haskell (T-H) method to study this problem. proposed the generalized reflection and transmission (GR/T) coefficient method to approach the same problem for the case of monopole sonic logging in single-phase elastic media.…”

Section: Introductionmentioning

confidence: 99%