Determining the transverse surface relaxivity of reservoir rocks: A critical review and perspective

Ge, Xin; Myers, Michael T.; Liu, Jianyu; Fan, Yiren; Zahid, Muhammad Aleem; Zhao, Jier; Hathon, Lori

doi:10.1016/j.marpetgeo.2021.104934

Cited by 35 publications

(28 citation statements)

References 130 publications

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“…where N is the Avogadro constant, A m is the cross-sectional area of the N 2 molecule, V 0 is the molar volume of the N 2 molecule at the standard temperature, and m is the mass of the sample to be tested. For the rock used in this study, the measured specific surface area is 7.617 m 2 /g and the calculated adsorption cumulative volume of pores is 0.011 cm 3 / g. The surface relaxivity can be expressed as [35,36]…”

Section: Resultsmentioning

confidence: 99%

Insights into Controlling Factors of Pore Structure and Hydraulic Properties of Broken Rock Mass in a Geothermal Reservoir

Zhang

et al. 2022

Lithosphere

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The filled broken rock mass in a geothermal reservoir under high-pressure work fluid and overburden stress is of great significance to the efficient operation of the geothermal system. The pore structure and hydraulic properties of the broken rock mass were quantitatively investigated by the nuclear magnetic resonance (NMR) technology and the non-Darcy models. The broken rock mass at the lower compressive stress levels shows stronger compressibility, and the broken gangue with more small particles shows stronger stress sensitivity. The seepage pores in broken rock can be characterized by the fractal theory, and the fractal dimension ranges from 2.749 to 2.861, which is positively correlated with compressive stress. The increase in Dp can be attributed to the shrinkage of macropores affected by the increasing compressive stress. The flow in broken rock mass under high pressure gradient shows significant nonlinearity verified by the Forchheimer equation and the Barree-Conway equation. We proposed a logistic regression model to characterize the effects of compressive stress and GSD on the permeability and the characteristic parameter of nonlinear flow in broken rock mass, which provides a potential method for evaluating the performance of the geothermal system based on the pore structure of the reservoir rock mass.

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Section: Resultsmentioning

confidence: 99%

Insights into Controlling Factors of Pore Structure and Hydraulic Properties of Broken Rock Mass in a Geothermal Reservoir

Zhang

et al. 2022

Lithosphere

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“…However, accurate determination of ρ 2 is a big challenge currently. Ge et al 35 reviewed the existing methods for determining ρ 2 of reservoir rocks. It was demonstrated that ρ 2 was affected by multiple factors, and currently, there was no universally accepted method because each method could only probe part of the pore system.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Compressibility of Multiscale Pore–Fractures in Fractured Low-Rank Coals by Low-Field Nuclear Magnetic Resonance

et al. 2021

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Evaluation of stress sensitivity of multiscale pores in coal seams stimulated by hydraulic fracturing or that disturbed by underground mining is significant to coalbed methane recovery and gas disaster control. In this work, two types of low-rank coals are selected to investigate the stress sensitivity of pore−fractures with different scales by the low-field nuclear magnetic resonance (LF-NMR) method. The compressibility changes of multiscale pores in intact coal cores and coal cores with self-supported and proppant-supported fractures under different loading paths are analyzed. The results show that the volume of pores decreases with the increasing confining stress, except some specific cases caused by water migration across pores with different scales. In the loading−unloading process, an "unloading memory effect" is observed. After three cycles of loading−unloading, the pore volume cannot recover to the initial value. The pore compressibility is not a constant but decreases with the increasing confining stress. Besides, the pore compressibility is also scale-dependent, and the compressibility of fractures can be 10 times greater than that of the micropores. The existence of the artificial fracture can obviously increase the compressibility of the coal, while the introduction of the proppants can significantly reduce the fracture compressibility. During the loading−unloading process, there exists a 2−30% loss of the compressibility, even when the confining stress decreases to the initial value. The compressibility measured by LF-NMR has a value and variation trend similar to that measured by the permeability−stress method, indicating that LF-NMR is an effective method for the compressibility tests of coal.

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“…This length scale, δ, normalized by the T 1,2, surface is well-known as the surface relaxivity, ρ 2 , which is the most important concept in relaxation studies in porous media. Surface relaxivity provides relationship between observed relaxation rate and pore size (Bowers et al 1995;Ge et al 2021). By assuming more free bulk fluid than the absorbed in surface layer (1-P > > P) and large S/V, the approximate expression reveals that the relaxation rate depends on the surface chemistry and material characteristic of the pore structure as following:…”

Section: Nmr Applications In Laboratory Scalementioning

confidence: 99%

“…Accordingly, the NMR signal provides relative pore size distribution. It follows that surface relaxivity is a key parameter in determination of pore size distribution (PSD) (Ge et al 2021;Jaeger et al 2009;P. Zhao et al 2020a, b).…”

Section: Pore Size Distributionmentioning

confidence: 99%

“…They also have MR scanner which reads at multiple depth of investigation up to 10.2 cm, in addition to the LWD tool referred as proVISION plus (DePavia et al 2003;Vij et al 2018). Halliburton provides the highest depth of investigation (102 cm) tool with operating frequency ranges between 0.547 and 1.183 MHz with minimum echo time = 0.2 ms referred as XMR (Chen et al 2018a, b;Ge et al 2021). Furthermore, they developed LWD tool, called MRIL-WD, with lower operating frequency (0.5 MHz with minimum echo time = 0.5 ms).…”

Section: Introductionmentioning

confidence: 99%

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A review on the applications of nuclear magnetic resonance (NMR) in the oil and gas industry: laboratory and field-scale measurements

Elsayed

Isah

Hiba

et al. 2022

J Petrol Explor Prod Technol

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This review presents the latest update, applications, techniques of the NMR tools in both laboratory and field scales in the oil and gas upstream industry. The applications of NMR in the laboratory scale were thoroughly reviewed and summarized such as porosity, pores size distribution, permeability, saturations, capillary pressure, and wettability. NMR is an emerging tool to evaluate the improved oil recovery techniques, and it was found to be better than the current techniques used for screening, evaluation, and assessment. For example, NMR can define the recovery of oil/gas from the different pore systems in the rocks compared to other macroscopic techniques that only assess the bulk recovery. This manuscript included different applications for the NMR in enhanced oil recovery research. Also, NMR can be used to evaluate the damage potential of drilling, completion, and production fluids laboratory and field scales. Currently, NMR is used to evaluate the emulsion droplet size and its behavior in the pore space in different applications such as enhanced oil recovery, drilling, completion, etc. NMR tools in the laboratory and field scales can be used to assess the unconventional gas resources and NMR showed a very good potential for exploration and production advancement in unconventional gas fields compared to other tools. Field applications of NMR during exploration and drilling such as logging while drilling, geosteering, etc., were reviewed as well. Finally, the future and potential research directions of NMR tools were introduced which include the application of multi-dimensional NMR and the enhancement of the signal-to-noise ratio of the collected data during the logging while drilling operations.

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Determining the transverse surface relaxivity of reservoir rocks: A critical review and perspective

Cited by 35 publications

References 130 publications

Insights into Controlling Factors of Pore Structure and Hydraulic Properties of Broken Rock Mass in a Geothermal Reservoir

Insights into Controlling Factors of Pore Structure and Hydraulic Properties of Broken Rock Mass in a Geothermal Reservoir

Evaluation of Compressibility of Multiscale Pore–Fractures in Fractured Low-Rank Coals by Low-Field Nuclear Magnetic Resonance

A review on the applications of nuclear magnetic resonance (NMR) in the oil and gas industry: laboratory and field-scale measurements

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