Multicomponent induction response in a borehole environment

Wang, Tsili; Yu, Liming; Fanini, Otto

doi:10.1190/1.1620624

Cited by 21 publications

(7 citation statements)

References 13 publications

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“…three sources and three sensors, with axes orthogonal to each other (Anderson et al, 2008). These tools are commercially referred to as triaxial (Krigshäuser et al, 2000) or multicomponent induction tools (Wang et al, 2003). The responses of the three arrangements of coils are simultaneously registered on multiple channels at multiple frequencies (tens of kHz) and source-sensor spacing.…”

Section: Introductionmentioning

confidence: 99%

Revisiting Some Old Unexplained Effects in Induction Logs Within Laminated Formations With the Triaxial Induction Tool

Carvalho¹,

Régis²

2016

Rev. Bras. Geof.

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ABSTRACT. Modern induction triaxial or multicomponent well logging tools provide resistivity anisotropy logs, and estimates of the electrical resistivity of sand laminae in thinly laminated formations. In this paper, coaxial and coplanar vertical logs were modeled in one-dimensional (1D) laminated packages and in their equivalent anisotropic beds, neglecting the presence of the borehole and the invasion zones, to simulate geological environments of hydrocarbon reservoirs with resistivity anisotropy. The objective of this paper is twofold: to perform a quantitative analysis of the anisotropy level of a thinly laminated reservoir as compared to an equivalent anisotropic bed, and, in doing so, to revisit some old and unexplained effects that appear on the triaxial induction logs. These subtle effects may have only a faint influence on the logs themselves, but their study contribute to our understanding of the electromagnetic phenomena involved in the induction logging. The results show that the coaxial logs in the laminated formation converge to the equivalent anisotropic bed response much sooner than the coplanar logs. They also show that there is a considerable difference between the anisotropy index obtained by the triaxial induction tool within laminated formations and the anisotropy coefficient of its equivalent anisotropic bed, even for extremely thin laminae thicknesses.Keywords: well logging, multicomponent induction tools, laminated reservoirs, electrical anisotropy. RESUMO.As atuais ferramentas de perfilagem em poço por indução eletromagnética, denominadas triaxias ou multicomponentes, fornecem perfis de anisotropia elétrica e permitem estimar a resistividade de lâminas de areia em ambientes finamente laminados. Neste artigo, os perfis dos arranjos coaxial e coplanar de bobinas foram simulados em modelos unidimensionais (1D) de sequências laminadas e de suas respectivas camadas anisotrópicas equivalentes, negligenciando o poço e as zonas de invasão, visando simular ambientes de reservatório de hidrocarbonetos com anisotropia elétrica. Os objetivos deste trabalho são basicamente dois: fazer uma análise comparativa do grau de anisotropia de reservatórios laminados com relação a uma camada anisotrópica equivalente e, no desenrolar deste estudo, reavaliar alguns antigos e ainda não explicados efeitos presentes nos perfis de indução. Estes efeitos têm apenas uma sutil influência nos perfis, embora sejam importantes para uma clara compreensão dos fenômenos eletromagnéticos envolvidos na perfilagem. Pelos resultados pode-se verificar que ao reduzir progressivamente as espessuras das lâminas, os perfis do arranjo coaxial convergem para os da camada anisotrópica equivalente bem mais rápido do que os perfis do arranjo coplanar. Pode-se verificar também que, mesmo para lâminas extremamente finas, existe uma considerável diferença entre oíndice de anisotropia, obtido com as ferrramentas triaxiais, com relação aoíndice de anisotropia da camada equivalente.Palavras-chave: perfilagem de poço, ferramentas multicomponente...

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Section: Introductionmentioning

confidence: 99%

Revisiting Some Old Unexplained Effects in Induction Logs Within Laminated Formations With the Triaxial Induction Tool

Carvalho¹,

Régis²

2016

Rev. Bras. Geof.

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“…The electrical resistivity of oil-based drilling muds additionally depends on mixture composition, such as desired fluid weight and oilwater ratio. Because factors such as fluid density and oil:water ratio vary according to the needs of the particular well being drilled, a wide range of electrical resistivities exist for oil-based drilling fluids, ranging from as low as 500 Ω-m up to 30,000 Ω-m (Patil et al, 2010;Wang et al, 2003).…”

Section: Electrical Resistivitymentioning

confidence: 99%

“…These salts dissolve in the aqueous base fluid and form an electrolytic solution that is an electrical conductor. The result is a mixture whose electrical resistivity ranges from less than 1.0 Ω-m to approximately 15 Ω-m (Overton and Lipson, 1958;Schnoebelen et al, 1995;Wang et al, 2003;Patnode, 1949;Lamont, 1957).…”

Section: Electrical Resistivitymentioning

confidence: 99%

Kick Detection at the Bit: Early Detection via Low Cost Monitoring

Tost

Rose

Aminzadeh

et al. 2016

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“…5 None of the algorithms takes a 3D borehole environment into consideration, despite the fact that the tool responses are influenced by near-zone anomalies, such as drilling mud, tool eccentricity, and invasion. 6 Some of the responses can be severe. Figure 2 is an example of the eccentricity effect on the response of the YY response.…”

Section: Introductionmentioning

confidence: 99%

The Reduction of Near Zone Effects on the Multi-component Induction Logging Tool

Yu¹,

Rabinovich²,

Tabarovsky³

et al. 2003

SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe multi-component induction tool (3DEX) developed by Baker Atlas is comprised of three mutually orthogonal transmitter-receiver pairs measuring the secondary magnetic field at ten different frequencies. The measured data include the conventional coaxial component, Hzz, parallel to the borehole axis, and two coplanar components, Hxx and Hyy, perpendicular to the wellbore. In addition, two crosscomponents, Hxy and Hxz, are acquired to determine the formation dip and azimuth angles. The objective of this tool is to derive the horizontal and vertical resistivities of thinly laminated sand/shale sequences and anisotropic sands.The tool responses are influenced by near zone anomalies, such as drilling mud, elliptic invasion, drilling induced fracture, and tool eccentricity. Because the tool uses a relatively large transmitter-receiver separation, the near zone effects are fairly small on the coaxial component, Hzz, but they remain strong on the coplanar components, Hxx and Hyy.To reduce the near zone effects, a multi-frequency data processing technique was developed. We validated the technique with synthetic data produced by both 2-D and 3-D modeling algorithms. In an example of the borehole effect, the relative difference in responses with and without the borehole is 22% in the single frequency data but only 0.1% in the multifrequency processed data. In an example of the eccentricity effect, the relative difference in responses with and without tool centralization is 213% in the single frequency data but reduced to only 0.3% in the multi-frequency processed data. Therefore, after the multi-frequency data processing, a simple 1-D vertically layered model can be utilized for data interpretation because much of the near zone effects have been removed. The applicability of the MFF technique is limited in highly resistive formations due to a decreased signal-to-noise ratio as a result of the hardware noise .

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Multicomponent induction response in a borehole environment

Cited by 21 publications

References 13 publications

Revisiting Some Old Unexplained Effects in Induction Logs Within Laminated Formations With the Triaxial Induction Tool

Revisiting Some Old Unexplained Effects in Induction Logs Within Laminated Formations With the Triaxial Induction Tool

Kick Detection at the Bit: Early Detection via Low Cost Monitoring

The Reduction of Near Zone Effects on the Multi-component Induction Logging Tool

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