New 2-MHz Multiarray Borehole-Compensated Resistivity Tool Developed for MWD in Slim Holes

Bonner, Stephen D.; Tabanou, Jacques R.; Wu, Pin; Seydoux, Jean; Moriarty, K. A.; Seal, B.K.; Kwok, E.Y.; Kuchenbecker, Mark

doi:10.2523/30547-ms

Cited by 8 publications

(6 citation statements)

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“…Most published studies have focused on the properties of the dielectric constant at high frequency, usually in the range of kHzto MHz, or even GHz. [8][9][10][11][12][13][14] However, the phenomenon of low-frequency dispersion (LFD), which is widely observed in many materials, was not been properly recognized until its discovery by the Chelsea Dielectrics Group 15 and the investigation of its properties with increasing precision, as described in the book Dielectric Relaxation in Solids (DRS). Earlier studies proved that most rocks and minerals show dielectric dispersion in the low-frequency region from a few Hz to several MHz.…”

Section: Introductionmentioning

confidence: 99%

Study of the Low-Frequency Dispersion of Permittivity and Resistivity in Tight Rocks

Liu

JieTian

Deng

et al. 2016

IPCSE

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Obviously, in the low-frequency domain, the dielectric permittivity dispersion bears abundant information about the matrix, shale, fluid and pores, and even the geometry of the pores, their distribution, and the connectivity of the pore throat. For the case of tight reservoirs, a low frequency should be more useful to disclose the mysteries hidden in the rocks. This paper presented an experiment on tight limestone from Daanzhai Group, Jurassic formation, Sichuan Basin, and discussed the results in detail. In this paper, we mainly focused on the characteristics of the permittivity dispersion and its relationships with AbstractThis study investigated the frequency dispersion of the resistivity and permittivity in tight rocks of the Daanzhai Group, Jurassic formation, Sichuan Basin. Tight limestone cores were used in the experiment, and the frequency varied from 0.1Hz to 1kHzunder laboratory conditions. The permittivity and resistivity decrease as the frequency increases, but the changing rates of these two parameters are different, as the permittivity exhibits a more obvious dispersion than the resistivity at both low and high frequency. Over the whole frequency range, the change rate of the resistivity is very small and can even be neglected. The change rate of the permittivity, however, is very significant, and its difference reached several orders of magnitude. Besides this phenomenon, the frequency dispersion degree increases as the water saturation and concentration increase. Therefore, we establish a group of equations to describe this relationship between the frequency dispersion and water saturation, and water concentration. Unlike Archie's equation, which need multiple experimental parameters, the new formula can directly calculate the saturation from R p and C p or from D R and D C , only requiring two variables. Furthermore, frequency scanning test still implicates abundant information, which perhaps characterizes the pore structure, porosity, permeability and other properties of rocks or formations.Keywords: litho-electrical experiment, resistivity, permittivity, frequency dispersion

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Section: Introductionmentioning

confidence: 99%

Study of the Low-Frequency Dispersion of Permittivity and Resistivity in Tight Rocks

Liu

JieTian

Deng

et al. 2016

IPCSE

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“…2,3 Two transmitter antennas are positioned symmetrically 33-in. above and below the midpoint of two receiver antennas, which are separated by 22 in.…”

Section: Introductionmentioning

confidence: 99%

A Retrievable and Reseatable Propagation Resistivity Tool for Logging While Drilling and Logging While Tripping

Frey¹,

Argentier²,

Ross³

et al. 2006

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA new while-drilling propagation resistivity system with a novel architecture has been developed that greatly reduces lost-in-hole exposure and provides increased operational efficiency and flexibility. The downhole electronics, antennas, and battery are mounted in a retrievable and reseatable tool unit with a 1.75-in. outer diameter. This unit is seated in a 4.75-in., 6.75-in., or 8.25-in. special stainless steel collar that is engineered to be electromagnetically transparent. The tool measures phase shift and attenuation resistivity at 2 MHz and 400 KHz to provide borehole-compensated resistivity measurements at four independent depths of investigation. This service can be run with an existing measurement-whiledrilling (MWD) system to provide real-time data such that the combination is retrievable and reseatable in one operation. Alternately, the collar alone can be run while drilling, the tool unit can be lowered through the drill string into the collar, and measurements can be recorded while tripping out at speeds up to 1800 ft/hr. Combination of the data with cased-hole logs can be used to save operational time and improve logging success in difficult environments. The system has completed extensive field-testing. Several field examples and comparisons with while-drilling and wireline logs will be shown.

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“…The phase shift and attenuation responses of 2-MHz and 400-kHz propagation tools measure formation resistivity, [1][2][3][4][5][6][7][8][9] however, the formation dielectric constant increasingly affects the phase shift and attenuation as the formation resistivity increases. Hence, a correct understanding of how the dielectric constant affects the tool response is critical whenever the tool is operated in high resistivities.…”

Section: Introductionmentioning

confidence: 99%

Dielectric-Independent 2-MHz Propagation Resistivities

Wu¹,

Lovell²,

Clark³

et al. 1999

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAll commercial 2-MHz and 400-kHz propagation resistivity logging-while-drilling (LWD) tools use an assumed value or relationship for dielectric permittivity to derive independent resistivities from phase shift and attenuation measurements. This methodology has been used for over ten years. For resistivities below 100 Ω-m, the phase shift resistivity is not strongly affected by the assumed value of dielectric constant. In contrast, the attenuation resistivity is sensitive to the assumed dielectric constant above 10 Ω-m, and extremely sensitive above 50 Ω-m. A new empirical relationship between relative dielectric constant and resistivity is proposed to improve the phase shift and attenuation resistivities above 100 Ω-m. However, in high resistivity formations, and in unusual lithologies with exceptionally large dielectric permittivities, it is better to invert the measured phase shifts and attenuations together to obtain an apparent resistivity that is independent of the dielectric constant. This "dielectricindependent" resistivity will be free of possible errors caused by assuming a wrong value for dielectric permittivity. Even though phase shift and attenuation resistivities exhibit different vertical and radial response characteristics, simulations show that bed boundaries and moderate invasion do not adversely affect the computation of the dielectricindependent resistivity. In oil based mud, it is possible to read resistivities above 1000 Ω-m. This provides the ability to differentiate among high resistivity formations, but not necessarily the ability to measure a quantitative value. Three field examples illustrate the strengths and limitations of the dielectric-independent resistivity.

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New 2-MHz Multiarray Borehole-Compensated Resistivity Tool Developed for MWD in Slim Holes

Cited by 8 publications

References 0 publications

Study of the Low-Frequency Dispersion of Permittivity and Resistivity in Tight Rocks

Study of the Low-Frequency Dispersion of Permittivity and Resistivity in Tight Rocks

A Retrievable and Reseatable Propagation Resistivity Tool for Logging While Drilling and Logging While Tripping

Dielectric-Independent 2-MHz Propagation Resistivities

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