scholarly journals Microscopic Characteristic Analysis on Sandstone under Coupling Effect of Freeze–Thaw and Acidic Treatment: From Nuclear Magnetic Resonance Perspective

2020 ◽  
Vol 10 (16) ◽  
pp. 5699
Author(s):  
Songtao Yu ◽  
Hongwei Deng ◽  
Guanglin Tian ◽  
Junren Deng
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Acid Solution ◽  
Coupling Effect ◽  
Fractal Dimensions ◽  
Total Porosity ◽  
Characteristic Analysis ◽  
Freeze Thaw ◽  
Ph Decrease ◽  
Nuclear Magnetic

Microscopic characteristics greatly affect mechanical and physical properties as they exert vital impact on the stability and durability of materials. In this paper, widely distributed sandstone was chosen as the research object. Sandstone was treated with a coupled effect of Freeze–Thaw (F–T) weathering and acid solution, where freeze–thaw cycles were set as 0, 10, 20, 30 and 40 cycles, and the pH of the acid solution were set as 2.8, 4.2, 5.6 and 7.0, respectively. Then, nuclear magnetic resonance was applied to measure the microscopic characteristics of sandstone, then porosity, pore size distribution and permeability before the fractal dimensions were obtained and calculated. Results show that porosity increases when F–T cycles increase, and its increase grows with the pH of acid solution decrease during the first 10 F–T cycles. Macro porosity, meso porosity and micro porosity account for the largest, second largest and smallest ratio of porosity growth. Meso porosity, micro porosity and macro porosity account for the largest, second largest and smallest ratio of total porosity. Permeability increases obviously with F–T cycle increase, while acid erosion exerts little influence on permeability increment overall. Fractal dimensions of meso pores and macro pores increase with F–T cycle increase overall, and they increase with pH decrease overall. Porosity has strong exponentially correlation with permeability. Fractal dimensions of meso pores and macro pores have good linearly correlation with permeability, while correlation between porosity and fractal dimensions are not that obvious.

Nuclear Magnetic Resonance Logging While Drilling in Complex Lithology – Solution for a Glauconitic Sandstone Reservoir

2016 ◽  
Author(s):  
Ahmed Abouzaid ◽  
Holger Thern ◽  
Mohamed Said ◽  
Mohammad ElSaqqa ◽  
Mohamed Elbastawesy ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bound Water ◽  
Total Porosity ◽  
Accessory Minerals ◽  
Formation Evaluation ◽  
Rock Quality ◽  
Logging While Drilling ◽  
Bahariya Formation ◽  
Nuclear Magnetic

ABSTRACT The evaluation of logging data in shaly sand reservoirs can be a challenging task, particularly in the presence of accessory minerals such as glauconite. Accessory minerals affect the measurements of conventional logging tools, thus, introducing large uncertainties for estimated petrophysical properties and reservoir characterization. The application of traditional Gamma Ray and Density-Neutron crossover methods can become unreliable even for the simple objective of differentiating reservoir from non-reservoir zones. This was the situation for many years in the glauconite-rich Upper Bahariya formation, Western Desert, Egypt. Formation evaluation was challenging and the results often questionable. Adding Nuclear Magnetic Resonance (NMR) Logging While Drilling (LWD) data in three wells changed the situation radically. The NMR data unambiguously indicate pay zones and simplify the interpretation for accurate porosity and fluid saturation dramatically. Key to success is NMR total porosity being unaffected by the presence of accessory minerals. NMR moveable fluid directly points to the pay zones in the reservoir, while clay-bound and capillary-bound water volumes reflect variations in rock quality and lithology. Although the NMR total porosity is lithology independent, the presence of glauconite affects the NMR T2 distribution by shifting the water T2 response to shorter T2 times. This requires an adjustment of the T2 cutoff position for separating bound water from movable hydrocarbons. A varying T2 cutoff was computed by comparing NMR bound water to resistivity-based water saturation. The calibrated T2 cutoff exhibits an increase with depth indicating a decreasing amount of glauconite with depth throughout the Upper Bahariya formation. Based on these volumetrics, an improved NMR permeability log was calculated, now accurately delineating variations in rock quality throughout the different pay zones. In addition, viscosity was estimated from the oil NMR signal. The estimated values match the expected values very well and illustrate the potential of NMR to indicate viscosity variations. Many of these results are available today already in real-time by transmitting NMR T2 distributions to surface while drilling. Besides the application for formation evaluation, the data can be used to initiate optimized side-tracking and completion decisions directly after finishing the drilling operations.

Nuclear Magnetic Resonance Analysis of Air Entraining Natural Pumice Concrete Freeze-Thaw Damage

2014 ◽  
Vol 919-921 ◽  
pp. 1939-1943 ◽  
Author(s):  
Xiao Xiao Wang ◽  
Xiang Dong Shen ◽  
Hai Long Wang ◽  
Hong Xia Zhao
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Saline Solution ◽  
Nuclear Magnetic Resonance Analysis ◽  
Spectral Parameters ◽  
Freeze Thaw ◽  
Resonance Analysis ◽  
Concrete Damage ◽  
Intuitive Method ◽  
Nuclear Magnetic

Based on the existed research and analysis methods of air entraining natural pumice concrete freeze-thaw damage, nuclear magnetic resonance (NMR) detection technique was introduced in the present study. From the research of essence of freeze-thaw coupling-induced concrete damage in saline solution, natural pumice concrete porosity and transversal relaxation time T2 spectral parameters were used as criteria, and nuclear magnetic resonance imaging (NMRI) technology, an intuitive method was used to determine freeze-thaw damage quantitatively.

Formation of unilamellar vesicles by repetitive freeze-thaw cycles: characterization by electron microscopy and 31 P-nuclear magnetic resonance

2000 ◽  
Vol 29 (3) ◽  
pp. 184-195 ◽  
Author(s):  
Mounir Traïkia ◽  
Dror E. Warschawski ◽  
Michel Recouvreur ◽  
Jean Cartaud ◽  
Philippe F. Devaux
Keyword(s):  
Electron Microscopy ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Unilamellar Vesicles ◽  
Freeze Thaw ◽  
Nuclear Magnetic

scholarly journals The characteristic analysis of a nuclear magnetic resonance oscillator coupled with the phase-locked loop

AIP Advances ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 125220
Author(s):  
Qiyuan Jiang ◽  
Zhiguo Wang ◽  
Xiang Zhan ◽  
Hui Luo ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Phase Locked Loop ◽  
Characteristic Analysis ◽  
Resonance Oscillator ◽  
Nuclear Magnetic
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