scholarly journals Low-Field Nuclear Magnetic Resonance Characteristics of Biofilm Development Process

2021 ◽  
Vol 9 (12) ◽  
pp. 2466
Author(s):  
Yajun Zhang ◽  
Yusheng Lin ◽  
Xin Lv ◽  
Aoshu Xu ◽  
Caihui Feng ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Biofilm Formation ◽  
Development Process ◽  
Bacterial Cells ◽  
T2 Relaxation ◽  
Biofilm Growth ◽  
Low Field ◽  
Biofilm Development ◽  
Nuclear Magnetic

To in situ and noninvasively monitor the biofilm development process by low-field nuclear magnetic resonance (NMR), experiments should be made to determine the mechanisms responsible for the T2 signals of biofilm growth. In this paper, biofilms were cultivated in both fluid media and saturated porous media. T2 relaxation for each sample was measured to investigate the contribution of the related processes to T2 relaxation signals. In addition, OD values of bacterial cell suspensions were measured to provide the relative number of bacterial cells. We also obtained SEM photos of the biofilms after vacuum freeze-drying the pure sand and the sand with biofilm formation to confirm the space within the biofilm matrix and identify the existence of biofilm formation. The T2 relaxation distribution is strongly dependent on the density of the bacterial cells suspended in the fluid and the stage of biofilm development. The peak time and the peak percentage can be used as indicators of the biofilm growth states.

Application of Low-Field Nuclear Magnetic Resonance (LFNMR) in Characterizing the Dissociation of Gas Hydrate in a Porous Media

2021 ◽  
Vol 35 (3) ◽  
pp. 2174-2182
Author(s):  
Yongchao Zhang ◽  
Lele Liu ◽  
Daigang Wang ◽  
Pengfei Chen ◽  
Zhun Zhang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Porous Media ◽  
Magnetic Resonance ◽  
Gas Hydrate ◽  
Low Field ◽  
Nuclear Magnetic

Textural and pore size analysis of carbonates from integrated core and nuclear magnetic resonance logging: An Arbuckle study

2015 ◽  
Vol 3 (1) ◽  
pp. SA77-SA89 ◽  
Author(s):  
John Doveton ◽  
Lynn Watney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Pore Size ◽  
Relaxation Times ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Nmr Logging ◽  
The Core ◽  
Nuclear Magnetic

The T2 relaxation times recorded by nuclear magnetic resonance (NMR) logging are measures of the ratio of the internal surface area to volume of the formation pore system. Although standard porosity logs are restricted to estimating the volume, the NMR log partitions the pore space as a spectrum of pore sizes. These logs have great potential to elucidate carbonate sequences, which can have single, double, or triple porosity systems and whose pores have a wide variety of sizes and shapes. Continuous coring and NMR logging was made of the Cambro-Ordovician Arbuckle saline aquifer in a proposed CO2 injection well in southern Kansas. The large data set gave a rare opportunity to compare the core textural descriptions to NMR T2 relaxation time signatures over an extensive interval. Geochemical logs provided useful elemental information to assess the potential role of paramagnetic components that affect surface relaxivity. Principal component analysis of the T2 relaxation time subdivided the spectrum into five distinctive pore-size classes. When the T2 distribution was allocated between grainstones, packstones, and mudstones, the interparticle porosity component of the spectrum takes a bimodal form that marks a distinction between grain-supported and mud-supported texture. This discrimination was also reflected by the computed gamma-ray log, which recorded contributions from potassium and thorium and therefore assessed clay content reflected by fast relaxation times. A megaporosity class was equated with T2 relaxation times summed from 1024 to 2048 ms bins, and the volumetric curve compared favorably with variation over a range of vug sizes observed in the core. The complementary link between grain textures and pore textures was fruitful in the development of geomodels that integrates geologic core observations with petrophysical log measurements.

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