Permeability Prediction for Low Porosity Rocks by Mobile NMR

Pape, H.; Arnold, Juliane; Pechnig, Renate; Clauser, Christoph; Talnishnikh, E.; Anferova, S.; Blümich, Bernhard

doi:10.1007/978-3-0346-0122-1_18

Cited by 14 publications

(17 citation statements)

References 18 publications

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“…Generally, this susceptibility threshold will shift to smaller values for NMR experiments at higher Larmor frequencies and vice versa. These considerations concur with observations from laboratory studies on low‐porosity reservoir rocks (Pape et al, 2009). In practice, to estimate the pore‐size‐dependent effective surface relaxivity by inverse modeling, the susceptibility and porosity (e.g., NMR porosity) of the rock sample need to be independently measured.…”

Section: Resultssupporting

confidence: 89%

“…Simulations of transverse NMR relaxometry data support previous observations (e.g., Pape et al, 2009) indicating that the use of T 2 distributions as a permeability estimator tends to overestimate the contribution of smaller pores and thus to underestimate the rock permeability. To compensate for this drawback, the concept of an enhanced transverse surface relaxivity parameter that depends on pore size and rock susceptibility was introduced.…”

Section: Discussionsupporting

confidence: 78%

See 1 more Smart Citation

Microscale Simulations of NMR Relaxation in Porous Media Considering Internal Field Gradients

Mohnke

2010

Vadose Zone Journal

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Longitudinal and transverse nuclear magne c resonance (NMR) relaxa on signatures in porous rock were simulated on the microscale to examine and quan fy how physical hydrologic parameters, such as rock-surface proper es and pore sizes, aff ect longitudinal and transverse NMR signals of real, complex media. Parameters studied were: magne c fi eld strength, rock suscep bility, pore coupling, and surface reac vity. Using the fi nite element method (FEM), simula ons of the spa al-and me-dependent magne za on evolu on in arbitrary pore geometries, diff usion regimes, and heterogeneous distribu ons of rock surface proper es, i.e., surface relaxivity, were compiled using an adapted generic diffusion model coupled with magne c gradient fi eld calcula ons. The numerical simula ons were validated using analy cal solu ons that are available for simple pore geometries. We observed a pore-size-dependent ra o of transverse T 2 and longitudinal T 1 relaxa on mes, and thus a pore-size-related and rock-suscep bility-dependent eff ec ve transverse surface relaxivity was deduced. This can be used to improve es mates of pore sizes and thus of permeability from transverse NMR relaxometry measurements. Simula ons of connected pore systems showed signifi cant infl uences of interpore coupling at hydrologically relevant pore sizes, e.g., fi ne sands. Depending on the dominant diff usion regime, the typically heterogeneous distribu on of surface relaxivi es in rocks and sediments, i.e., geological noise, can lead to a signifi cant underes ma on of derived pore sizes and thus of permeability.Abbrevia ons: DG, diff usion gradient; FEM, fi nite element method; FID, free induc on decay; NMR, nuclear magne c resonance.In petrophysical applica ons of NMR, the measured relaxation signals originate from the fl uid-fi lled pore space. Hence, in water-saturated rocks or sediments, the water content directly corresponds to the initial amplitude of the recorded NMR relaxation signal. Th e relaxation rate (longitudinal/transverse relaxation time ratio T 1 /T 2 ) depends on the pore size and physicochemical properties of the rock-fl uid interface (surface relaxivity) and on the concentration of paramagnetic ions or molecules (e.g., dissolved O 2 ) in the fl uid phases (bulk relaxivity) (e.g., Bryar et al., 2000; Keating and Knight, 2007). Th erefore, NMR can provide estimates of hydraulic parameters, i.e., pore size distribution or permeability. In this respect, there is a large variety of empirical or semiempirical relations (Kenyon et al., 1988;Dunn, 2002;Sen et al., 1990). Other relations frequently used as permeability estimators from NMR are based on geometrical considerations such as the Kozeny-Carman model (Carman, 1956, Ch. 1). Th ese permeability estimators apply the analytical relations between pore size and NMR relaxation behavior derived by Brownstein and Tarr (1979) for single unconnected pores. Th ese relations, however, are limited to simple, idealized pore models such as cylinders, spheres, or planar shapes. Furthermore, the infl uence...

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Section: Resultssupporting

confidence: 89%

Section: Discussionsupporting

confidence: 78%

Microscale Simulations of NMR Relaxation in Porous Media Considering Internal Field Gradients

Mohnke

2010

Vadose Zone Journal

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“…Additionally, surface relaxivity is not only related to the lithology type or surface roughness, but also to different elements such as surface chemistry. Pape et al 22 suggested that surface relaxivity increases with a decrease in the pore radius. However, the relationships between the three properties (grain size, specific surface, and surface relaxivity) do not follow a distinctive trend or correlation of neither linear, power, nor exponential type.…”

Section: Nmr Surface Relaxivitymentioning

confidence: 99%

Retracted: A review of the nuclear magnetic resonance physics and application in petroleum industry

2016

Concepts Magnetic Resonance

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The above article from Concepts in Magnetic Resonance Part A, published online on November 1, 2017 in Wiley Online Library (http://onlinelibrary.wiley.com/), has been retracted following consultation between the authors, the journal Editor in Chief, Daniel D. Traficante, Assistant Editor David Rovnyak and Wiley Periodicals, Inc. The reason for the retraction is that it has been agreed that Figures 6‐11, 13, 14, and 22 were used without permission from the owner of the figures. Reference

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“…Pape et al [11] identified a relationship between the porosity and permeability of Rotliegend sandstone from a large dataset of experimental test results: k = 3 10 × 10 −11 ϕ + 7 46 × 10 −09 ϕ 2 + 1 91ϕ 10 2…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Sandstone Permeability under Plastic Flow: Permeability Evolution Law with Stress Increment

Gong

Chen

et al. 2019

Geofluids

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Permeability is an important physical property of rock. In rock and rock-like materials, permeability after yielding is closely related to plastic flow behavior. Theoretical analysis and experimental investigations are effective and reliable ways of studying the evolution of permeability. In this paper, fluid flow tests of sandstone samples under 11 stress states were conducted using the MTS 816.02 rock mechanics testing system and a self-designed permeation system. A new plastic flow rule was proposed based on the Mohr-Coulomb yield criterion and a nonassociated flow rule. The applicability of the flow rule was verified by comparing the estimated and experimental values of the equivalent shear strain of the Mohr–Coulomb criterion. Two new coefficients were defined to reflect the influence of the volume deformation and shear deformation on the permeability. A permeability model for plastic flow was established, which can be used to calculate both single-step and multistep permeability estimates of the sandstone samples during plastic flow. The errors of both estimation methods were analyzed. The experimental results showed that the plastic multiplier for the sandstone samples was positive during unloading conditions and negative during loading conditions. The experimental value error of the single-step permeability estimation was less than 16.5%. The experimental value errors of the multistep permeability estimations varied between 15.6% and 16.7%, indicating that the iterative format of the multistep permeability estimation method was generally stable and highly precise. A comparison of the permeability influence coefficients indicated that the influence of the equivalent shear strain on the permeability was smaller than that of the volumetric strain.

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Permeability Prediction for Low Porosity Rocks by Mobile NMR

Cited by 14 publications

References 18 publications

Microscale Simulations of NMR Relaxation in Porous Media Considering Internal Field Gradients

Microscale Simulations of NMR Relaxation in Porous Media Considering Internal Field Gradients

Retracted: A review of the nuclear magnetic resonance physics and application in petroleum industry

Experimental Investigation on Sandstone Permeability under Plastic Flow: Permeability Evolution Law with Stress Increment

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