Permeability relation with other petrophysical parameters for periodic porous media

Dunn, Keh‐Jim; LaTorraca, Gerald A.; Bergman, David J.

doi:10.1190/1.1444552

Cited by 39 publications

(27 citation statements)

References 22 publications

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“…Sen et al (26) introduced the formation factor (F) into the correlation of k with T 1 , and found k ¼ aðT 1 =FÞ b to be a good predictor of the viscous permeability in clay-bearing sandstones. Various kðF; T 1 Þ correlations were explored in later works dealing with sandstones (12,16,17) and model porous media (15), with mixed results: They were found to perform better than the corresponding kðf; T 1 Þ relations in one case (15), but made no practical difference in all other cases.…”

Section: Introductionmentioning

confidence: 93%

“…In the fast and intermediate diffusion regime, the condition t b ) '/r is typically met for sandstones and other porous media (4, 9, 13, 14, 18), but not necessarily in systems of very low r or high ' (15,(32)(33)(34). In the slow diffusion regime, the condition t b ) ' 2 /D is also not necessarily met in systems of very low D or high ' (33).…”

Section: Diffusion Regimes In Nmr Processesmentioning

confidence: 99%

“…This gave rise to a number of follow-up studies investigating further the correlation k ¼ aðf 2 T 1 Þ 2b [1] both for sandstones (9)(10)(11)(12) and other porous media (13)(14)(15). Some works explored different kðf; T 1 Þ correlations as well (4,11,(15)(16)(17)(18), while others investigated correlations of the viscous permeability to the transverse (spin-spin) relaxation time constant, T 2 (3,(19)(20)(21)(22)(23)(24). Other permeability models widely used in oilfield applications involve the fraction of irreducible fluid saturation (1) or, equivalently, the ratio of free-to-bound fluid in the porous rock (20,21).…”

Section: Introductionmentioning

confidence: 97%

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Introducing dimensionless parameters into the correlation of NMR relaxation time to transport properties of porous media

Tomadakis

2007

Concepts Magnetic Resonance

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Dimensionless parameters representing the viscous permeability (k) and NMR relaxation time (T 1 ) of particle beds, while accounting also for the particle size, are shown to improve drastically the accuracy of k-T 1 correlations in the slow diffusion regime, in the absence of bulk relaxation effects. The finding is based on a regression analysis of numerical results for k and T 1 in both random and ordered isotropic and anisotropic beds of fibers. Use of the formation factor (F ) improves further the accuracy of the correlations only for the strongly anisotropic unidirectional arrays of fibers. A survey of related literature reveals an extensive effort in recent years in upgrading k-T 1 correlations, driven primarily by applications in petroleum and gas field exploration and recovery.

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Section: Introductionmentioning

confidence: 93%

Section: Diffusion Regimes In Nmr Processesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Introducing dimensionless parameters into the correlation of NMR relaxation time to transport properties of porous media

Tomadakis

2007

Concepts Magnetic Resonance

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“…The proportionality constant between the particle flux density, , and the concentration gradient, (25) describes the time derivative of the concentration for systems that are not in their equilibrium state. Generally speaking, the diffusion coefficient D i of a component is also a function of its concentration.…”

Section: Continuum Transport: Fick's Laws Of Diffusionmentioning

confidence: 99%

Fluid-Rock Characterization and Interactions in NMR Well Logging

Hirasaki¹,

Mohanty²

2005

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Objective: To characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging.This project is a partnership between Professor George J. Hirasaki at Rice University and Professor Kishore Mohanty at University of Houston. In addition to the DOE, a consortium of oil companies and service companies supports this project.The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity.Oil based drilling fluids can have an adverse effect on NMR well logging if it alters the wettability of the formation. The effect of various surfactants on wettability and surface relaxivity are evaluated for silica sand.The relation between the relaxation time and diffusivity distinguishes the response of brine, oil, and gas in a NMR well log. A new NMR pulse sequence in the presence of a field gradient and a new inversion technique enables the T 2 and diffusivity distributions to be displayed as a two-dimensional map.The objectives of pore morphology and rock characterization are to identify vug connectivity by using X-ray CT scan, and to improve NMR permeability correlation.Improved estimation of permeability from NMR response is possible by using estimated tortuosity as a parameter to interpolate between two existing permeability models. 3 EXECUTIVE SUMMARYThe fluid properties characterization is summarized as a chapter written for an AAPG book on NMR well logging. It describes the departure of live oils from correlations based on dead oils. Mixing rules are developed for gaseous mixtures of methane, ethane, propane, carbon dioxide, and nitrogen. The coupling between the relaxation time distribution and the diffusivity distribution is demonstrated with a binary mixture of hexane and squalene. Measurements of crude oils show that the T 1 , LM and T 2 , LM are equal at low viscosity but the T 1 , LM approach a plateau that is a function of viscosity and Larmor frequency. The hydrogen index of live oils can be estimated from measurements on the stock tank oil and live oil PVT data.Oil based drilling fluids can have an adverse effect on NMR well log interpretation if it alters the wettability from the natural condition of the reservoir.To gain an understanding of the effect of additives on NMR response, several surfactants were added to a base oil and its effect was evaluated on silica sand.A fatty acid, stearic acid, has no effect. However, a cationic surfactant and a commercial emulsifier alter wettability and increase the surface relaxivity of oil.New down-hole nuclear magnetic resonance (NMR) measurement and interpretation techniques have substantially improved fluid and reservoir characterization. These techniques take advantage of the magnetic field gradient of the logging tools to make diffusion sensitive NMR measurements.New NMR pulse sequences called "diffusion-editing" (DE)...

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“…In addition to the experimental data, artificial porous media were computationally generated and studied. Dunn et al (1998Dunn et al ( ,1999 studied periodic porous systems composed of arrays of touching and overlapping spheres, Øren et al (2002) reconstructed three-dimensional sandstone samples by a processbased reconstruction method, and Hidajat et al (2002) made use of two-point pore-pore correlation functions to construct porous media. They simulated or calculated the NMR properties and the permeabilities on the artificial porous media and studied their correlations.…”

mentioning

confidence: 99%

NMR Characterizations of Properties of Heterogeneous Media

Chang¹,

Choi²,

Hollenshead³

et al. 2005

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A critical and long-standing need within the petroleum industry is the specification of suitable petrophysical properties for mathematical simulation of fluid flow in petroleum reservoirs (i.e., reservoir characterization). The development of accurate reservoir characterizations is extremely challenging. Property variations may be described on many scales, and the information available from measurements reflect different scales. In fact, experiments on laboratory core samples, well-log data, well-test data, and reservoir-production data all represent information potentially valuable to reservoir characterization, yet they all reflect information about spatial variations of properties at different scales.Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) provide enormous potential for developing new descriptions and understandings of heterogeneous media. NMR has the rare capability to probe permeable media non-invasively, with spatial resolution, and it provides unique information about molecular motions and interactions that are sensitive to morphology. NMR well-logging provides the best opportunity ever to resolve permeability distributions within petroleum reservoirs.We develop MRI methods to determine, for the first time, spatially resolved distributions of porosity and permeability within permeable media samples that approach the intrinsic scale: the finest resolution of these macroscopic properties possible. To our knowledge, this is the first time that the permeability is actually resolved at a scale smaller than the sample.In order to do this, we have developed a robust method to determine of relaxation distributions from NMR experiments and a novel implementation and analysis of MRI experiments to determine the amount of fluid corresponding to imaging regions, which are in turn used to determine porosity and saturation distributions. We have developed a novel MRI experiment to determine velocity distributions within flowing experiments, and developed methodology using that data to determine spatially resolved permeability distributions.We investigate the use of intrinsic properties for developing improved correlations for predicting permeability from NMR well-logging data and for obtaining more accurate estimates of multiphase flow properties-the relative permeability and capillary pressure-from displacement experiments. We demonstrate the use of MRI measurements of saturation and relaxation for prediction wetting-phase relative permeability for unstable experiments. Finally, we developed an improved method for determining surface relaxivity with NMR experiments, which can provide better descriptions of permeable media microstructures and improved correlations for permeability predictions.ii

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Permeability relation with other petrophysical parameters for periodic porous media

Cited by 39 publications

References 22 publications

Introducing dimensionless parameters into the correlation of NMR relaxation time to transport properties of porous media

Introducing dimensionless parameters into the correlation of NMR relaxation time to transport properties of porous media

Fluid-Rock Characterization and Interactions in NMR Well Logging

NMR Characterizations of Properties of Heterogeneous Media

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