NMR characterization of hydrocarbon gas in porous media

Hari, Parameswar; Chang, C.T.Philip; Kulkarni, R. N.; Lien, J.R.; Watson, A. T.

doi:10.1016/s0730-725x(98)00057-5

Cited by 18 publications

(10 citation statements)

References 6 publications

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“…The transverse (T 2 ) and longitudinal (T 1 ) relaxation times of bulk methane gas were measured for a wide range of pressures from 3.5 MPa to 68.9 MPa at 22 • C. The critical pressure and temperature of methane are 4.6 MPa and -82.75 • C respectively, and therefore most experiments were conducted in the super critical state. The measured T 1 relaxation times are consistent with the literature data at the low pressure range measured by Watson et al [20] as shown in Fig. 3.…”

Section: A Relaxation Of Free Methane Gassupporting

confidence: 91%

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Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Papaioannou

Kausik

2015

Phys. Rev. Applied

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The storage properties of methane gas in Vycor porous glass (5.7 nm) are characterized in a wide pressure range from 0.7 MPa-89.7 MPa using Nuclear Magnetic Resonance (NMR). We demonstrate the capability of high field NMR relaxometry for the determination of the methane gas storage capacity and the measurement of the Hydrogen Index, to a high degree of accuracy. This helps determine the excess gas in the pore space which can be identified to exhibit Langmuir properties in the low pressure regime of 0.7 MPa to 39.6 Mpa. The Langmuir model enables us to determine the equilibrium density of the monolayer of adsorbed gas to be 8.5% lower than that of liquid methane. We also identify the signatures of multilayer adsorption at the high pressure regime from 39.6 Mpa to 89.7 Mpa and use the Brunauer-Emmet-Teller (BET) theory to determine the number of adsorbed layers of methane gas. We show how these measurements help us differentiate the gas stored in the Vycor pore space into free and adsorbed fractions for the entire pressure range paving way for similar applications such as studying natural gas storage in gas shale rock or hydrogen storage in carbon nanotubes. arXiv:1507.06861v2 [physics.geo-ph] 3 Sep 2015

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Section: A Relaxation Of Free Methane Gassupporting

confidence: 91%

“…The reduced value of T2 in comparison to T1 is because of the interactions with the sample tube walls. The literature values of T 1literature (magenta) are taken from Ref [20]…”

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confidence: 99%

Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Papaioannou

Kausik

2015

Phys. Rev. Applied

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“…The paper focuses on the methods and results to date. non-destructive analytical method of detecting hydrocarbons in reservoirs (3) and characterizing the hydrocarbon gas (4) . Generally, the NMR spectrum can provide three types of information: the quantities of the fluids in the rock, the mobility (viscosity) of these fluids and information about the pores that contain these fluids.…”

Section: Introductionmentioning

confidence: 99%

Characterizing Moisture and Gas Content of Coal by Low-Field NMR

Guo

Mannhardt

Kantzas

2007

Journal of Canadian Petroleum Technology

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Coalbed Methane (CBM) shows great potential to be an important energy source. One key factor for the successful development of CBM processes is to characterize coal on its moisture and gas content. Usually, the moisture and gas content of coal are determined from laboratory analysis. Low-field nuclear magnetic resonance (NMR) is a relatively new technique used in logging and in the analysis of fluids contained in reservoir rocks. This paper investigates the potential for coal characterization by low-field NMR. Low-field NMR detects hydrogen-bearing molecules and, in reservoir rock samples, distinguishes between ‘free’ bulk fluid and ‘bound’ surface fluid. Coal contains free water in the cleats as well as moisture that forms an integral part of the coal structure. Methane gas is a light hydrocarbon gas and coal contains free methane gas in fractures and adsorbed methane in internal surfaces. NMR characterization of moisture and adsorbed gas in coal and implications for moisture, adsorption isotherm and gas content measurements are explored. Experiments of moisture-free coal, moist coal and coal/water mixtures indicated drastically different spectra. From these spectra, free and bound water could be estimated using a methodology that is currently applied in clay-rich formations. In this paper, two sets of data are presented. First, measurements at ambient conditions provided a reference to other conventional moisture and cutoff data. Second, a high-pressure cell for the measurement of adsorbed coal was used and comparisons were made. Coal samples in the form of powder and chunk were used. The paper focuses on the methods and results to date. Introduction Coalbed methane (CBM) has evolved into a commercially profitable source of natural gas. Canada has vast resources of coal and it has been estimated that the total in-place reserves are 36 ? 1012 m3. Over 60% of Canada's CBM assets are in Alberta(1). Coalbed methane has the potential of contributing a significant portion of Canadian natural gas production in the near future. One key factor for the successful development of CBM processes is to characterize coal on its moisture and gas content. Usually, the moisture of coal is determined from coal proximate analysis and the gas content of coal is determined by the desorption measurement in the laboratory. Low-field NMR is a relatively new technique used in logging and in the analysis of fluids contained in reservoir rocks. Nuclear magnetic resonance occurs when the nuclei of certain atoms (i.e. hydrogen proton) are immersed in a static magnetic field and exposed to a second oscillating magnetic field(2). NMR provides a non-destructive analytical method of detecting hydrocarbons in reservoirs(3) and characterizing the hydrocarbon gas(4). Generally, the NMR spectrum can provide three types of information: the quantities of the fluids in the rock, the mobility (viscosity) of these fluids and information about the pores that contain these fluids. As a source rock and at the same time a reservoir rock, coal contains large amounts of water and methane. Water exists as free water in the cleats as well as the moisture that forms an integral part of the coal structure.

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“…The effect of T E is more obvious with the presence of mineralogical iron such as ferrihydrite, goethite, hematite, lepidocrocite, and magnetite (Keating & Knight, ). What is more, the spectrum may be shifted significantly with the variation of T E due to the difference in diffusivity of different fluids in pores (Hari et al, ).…”

Section: Introductionmentioning

confidence: 99%

A Practical Method to Compensate for the Effect of Echo Spacing on the Shale NMRT₂Spectrum

Zhao

Zhang

et al. 2019

Earth and Space Science

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The low field nuclear magnetic resonance (NMR) technique is considered as one of the most effective methods to characterize the pore size and fluid distribution in geophysical prospecting. The signal of NMR is noninvasive and lithology independent, while the effect of NMR responses influenced by the echo spacing (T E ) is significant when applied to unconventional reservoirs which are featured with ultralow porosity and pore radius. T E is expected to be as low as possible to ensure most of the hydrogen signals are accounted for, but it is hard to achieve in downhole NMR measurement. We develop a practical method to compensate for the influence of T E on the transversal relaxation time (T 2 ) spectrum of shale. Based on the experiments with different T E , the relationship between the NMR calibrated porosity and the T E is established to recover the signal amplitude. The effect of T E on the peak position is investigated, and then an empirical equation is constructed to move the peak position to its original state. By the above two-step correction algorithm, the T 2 spectrums of shale at large T E are compensated precisely. The proposed method provides an effective way to obtain the real T 2 spectrum and achieves good results in the downhole NMR data processing of shale reservoir.

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NMR characterization of hydrocarbon gas in porous media

Cited by 18 publications

References 6 publications

Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Characterizing Moisture and Gas Content of Coal by Low-Field NMR

A Practical Method to Compensate for the Effect of Echo Spacing on the Shale NMRT₂Spectrum

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NMR characterization of hydrocarbon gas in porous media

Cited by 18 publications

References 6 publications

Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Methane Storage in Nanoporous Media as Observed via High-Field NMR Relaxometry

Characterizing Moisture and Gas Content of Coal by Low-Field NMR

A Practical Method to Compensate for the Effect of Echo Spacing on the Shale NMRT2Spectrum

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A Practical Method to Compensate for the Effect of Echo Spacing on the Shale NMRT₂Spectrum