scholarly journals Method of Calculating Secondary Porosity of Reef Limestone Reservoir by Casting Thin Section Calibrating Nuclear Magnetic T 2 Spectrum

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Bin Zhao ◽  
Zhaoping Li ◽  
Chuqiao Gao ◽  
Guoyi Zhang ◽  
Jinbo Wu ◽  
...  
Keyword(s):  
Thin Section ◽  
Oil And Gas ◽  
Morphological Characteristics ◽  
Total Porosity ◽  
Surface Porosity ◽  
Secondary Porosity ◽  
The Monte Carlo Method ◽  
Reef Limestone ◽  
Calculation Results ◽  
Nuclear Magnetic

Secondary pores are the main reservoir space and transportation channel of oil and gas in reef limestone reservoir. At present, the main method of calculating secondary porosity is restricted by the morphological characteristics of porosity spectrum, regional artificial influence, and accuracy of calculation. We present a new method for calculating secondary porosity of reef limestone reservoir by the nuclear magnetic resonance T 2 spectrum which is calibrated by casting thin section. We begin with analyzing and determining the high correlation between the surface porosity of casting thin section and the total porosity. The objective is confirming the feasibility of the method of calculating secondary porosity by using thin-section information calibrate. Then, we use the surface porosity of thin section as the calibrating data and find the T 2 relaxation time corresponding to the best correlation between the secondary porosity and the secondary surface porosity of casting thin section, that is, the T 2 cutoff value of secondary porosity, through the Monte Carlo method. Finally, we calculate the secondary porosity by using the functional relationship between the secondary surface porosity and the surface porosity. The statistical analysis shows that the method of calculating secondary porosity effectively improves the calculation accuracy of secondary porosity. The secondary porosity calculation results have a high correlation with the reservoir productivity.

scholarly journals Porosity evolution of high-quality reservoirs in deep Palaeogene lacustrine carbonate rocks in the central Bohai Sea

2018 ◽  
Vol 36 (5) ◽  
pp. 1136-1156 ◽  
Author(s):  
Yuanhua Qing ◽  
Zhengxiang Lü ◽  
Xiandong Wang ◽  
Xiuzhang Song ◽  
Shunli Zhang ◽  
...  
Keyword(s):  
Bohai Sea ◽  
Oil And Gas ◽  
Early Stage ◽  
Reservoir Rock ◽  
Secondary Porosity ◽  
Authigenic Minerals ◽  
Porosity Evolution ◽  
Lacustrine Carbonate ◽  
Reservoir Porosity ◽  
Pore Lining

The oil and gas in the Palaeogene lacustrine carbonate rock reservoirs in the Bohai Sea accumulated during several periods. The reservoir porosity formed during each period affected the degree of accumulation that occurred. In this paper, the percentages of particles, authigenic minerals and pores in the reservoir bed were calculated with the statistical method of microstructure analysis. The formation time was determined with an isotopic analysis of the authigenic carbonate minerals and the homogenization temperature of the gas–liquid inclusions. The percentages of the primary intergranular pores that formed during the different stages were recovered based on the compaction features both before and after the formation of the major authigenic minerals. The evolution of porosity was thus described quantitatively and chronologically, employing the percentages of the residual primary intergranular pores, visceral cavity pores and dissolved pores at the different burial depths. The results indicate that in the initial sediments of the reservoir rock, the primary intergranular porosity was 32.4%. During the early burial stage, the total reservoir porosity increased by up to 46.9%, due to the addition of another type of primary pore, namely visceral cavity pores, which were generated from the decomposition of bioclasts. During the late, deep burial stage, the compaction reduced only 8.2% of the porosity, due to the support of the pore-lining dolomite precipitating during the early stage. Authigenic minerals occupied 12.6% of the porosity, and the dissolution created the secondary porosity by 3.8%. Good preservation of the visceral cavity pores and the growth of the pore-lining dolomites during the early stages are the major factors leading to the high reservoir porosity. The quantitative and chronological characteristics of the reservoir porosity evolution could be described accurately. The prediction of reservoir beds can be better guided than in previously reported methods by applying high resolution microscopic quantitative analysis technology and authigenic mineral timing analysis technology.

A FRACTAL SCALING LAW BETWEEN TORTUOSITY AND POROSITY IN POROUS MEDIA

Fractals ◽  
2020 ◽  
Vol 28 (02) ◽  
pp. 2050025
Author(s):  
PENG XU ◽  
LIPEI ZHANG ◽  
BINQI RAO ◽  
SHUXIA QIU ◽  
YUQING SHEN ◽  
...  
Keyword(s):  
Porous Media ◽  
Chemical Engineering ◽  
Oil And Gas ◽  
Scaling Law ◽  
Morphological Characteristics ◽  
Fractal Model ◽  
Statistical Characteristics ◽  
Scale Model ◽  
Reservoir Water ◽  
Flow Through

Hydraulic tortuosity is one of the key parameters for evaluating effective transport properties of natural and artificial porous media. A pore-scale model is developed for fluid flow through porous media based on fractal geometry, and a novel analytical tortuosity–porosity correlation is presented. Numerical simulations are also performed on two-dimensional Sierpinski carpet model. The proposed fractal model is validated by comparison with numerical results and available experimental data. Results show that hydraulic tortuosity depends on both statistical and morphological characteristics of porous media. The exponents for the scaling law between tortuosity and porosity depend on pore size distribution and tortuous fractal dimension. It has been found that hydraulic tortuosity indicates evident anisotropy for asymmetrical particle arrangements under the same statistical characteristics of porous media. The present work may be helpful to understand the transport mechanisms of porous materials and provide guidelines for the development of oil and gas reservoir, water resource and chemical engineering, etc.

An analysis of fractal dimension and tortuosity based on 2D numerical reconstruction model of reservoir rocks

2019 ◽  
Vol 7 (4) ◽  
pp. SJ1-SJ6 ◽  
Author(s):  
Liang Luo ◽  
Jiahong Jin ◽  
Wei Wei ◽  
Jianchao Cai
Keyword(s):  
Fractal Dimension ◽  
Oil And Gas ◽  
Universal Method ◽  
Structure Generation ◽  
Reservoir Rocks ◽  
Numerical Reconstruction ◽  
The Monte Carlo Method ◽  
Microstructure Parameters ◽  
Rock Model ◽  
The Relationship

The microstructure of reservoir rocks plays an important role in oil and gas accumulation and production. We examine a universal method to evaluate these properties of rocks, such as pore tortuosity, matrix porosity, and connectivity, and we respectively construct a 2D numerical reconstruction rock model with different microstructure parameters by the Monte Carlo method and the quartet structure generation set method. We further study the heterogeneity (characterized by fractal dimension and tortuosity) of the constructed image for reservoir rocks by the numerical and theoretical analysis and obtain the formulas for fractal dimension and tortuosity versus porosity. The simulation results show that the logarithmic relation is between the pore fractal dimension and porosity, and the relationship between tortuosity and porosity has the form of power. This process provided an important method to advance 2D reconstruction technology of reservoir rocks and effectively determine the relationship between microstructure and porosity.

Nuclear Magnetic Resonance Multiphase Flowmeters: Current Status and Future Prospects

2021 ◽  
pp. 1-14
Author(s):  
Masoumeh Zargar ◽  
Michael L. Johns ◽  
Jana M. Aljindan ◽  
Mohamed Nabil Noui-Mehidi ◽  
Keelan T. O'Neill
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Oil And Gas ◽  
Current Status ◽  
Process Industries ◽  
Phase Velocities ◽  
Individual Phase ◽  
Future Challenges ◽  
Complex Measurement ◽  
Nuclear Magnetic

Summary Multiphase flowmetering is a requirement across a range of process industries, particularly those that pertain to oil and gas. Generally, both the composition and individual phase velocities are required; this results in a complex measurement task made more acute by the prevalence of turbulent flow and a variety of flow regimes. In the current review, the main technical options to meet this metrology are outlined and used to provide context for the main focus on the use of nuclear magnetic resonance (NMR) technology for multiphase flowmetering. Relevant fundamentals of NMR are detailed as is their exploitation to quantify flow composition and individual phase velocities for multiphase flow. The review then proceeds to detail three NMR multiphase flowmeter (MPFM) apparatus and concludes with a consideration of future challenges and prospects for the technology.

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.

scholarly journals Preparation and morphology of sarcoplasmic reticulum terminal cisternae from rabbit skeletal muscle.

1984 ◽  
Vol 99 (3) ◽  
pp. 875-885 ◽  
Author(s):  
A Saito ◽  
S Seiler ◽  
A Chu ◽  
S Fleischer
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Thin Section ◽  
Membrane Surface ◽  
Freeze Fracture ◽  
Morphological Characteristics ◽  
Negative Staining ◽  
Section Electron ◽  
Terminal Cisternae

We have developed a procedure to isolate, from skeletal muscle, enriched terminal cisternae of sarcoplasmic reticulum (SR), which retain morphologically intact junctional "feet" structures similar to those observed in situ. The fraction is largely devoid of transverse tubule, plasma membrane, mitochondria, triads (transverse tubules junctionally associated with terminal cisternae), and longitudinal cisternae, as shown by thin-section electron microscopy of representative samples. The terminal cisternae vesicles have distinctive morphological characteristics that differ from the isolated longitudinal cisternae (light SR) obtained from the same gradient. The terminal cisternae consist of two distinct types of membranes, i.e., the junctional face membrane and the Ca2+ pump protein-containing membrane, whereas the longitudinal cisternae contain only the Ca2+ pump protein-containing membrane. The junctional face membrane of the terminal cisternae contains feet structures that extend approximately 12 nm from the membrane surface and can be clearly visualized in thin section through using tannic acid enhancement, by negative staining and by freeze-fracture electron microscopy. Sections of the terminal cisternae, cut tangential to and intersecting the plane of the junctional face, reveal a checkerboardlike lattice of alternating, square-shaped feet structures and spaces each 20 nm square. Structures characteristic of the Ca2+ pump protein are not observed between the feet at the junctional face membrane, either in thin section or by negative staining, even though the Ca2+ pump protein is observed in the nonjunctional membrane on the remainder of the same vesicle. Likewise, freeze-fracture replicas reveal regions of the P face containing ropelike strands instead of the high density of the 7-8-nm particles referable to the Ca2+ pump protein. The intravesicular content of the terminal cisternae, mostly Ca2+-binding protein (calsequestrin), is organized in the form of strands, sometimes appearing paracrystalline, and attached to the inner face of the membrane in the vicinity of the junctional feet. The terminal cisternae preparation is distinct from previously described heavy SR fractions in that it contains the highest percentage of junctional face membrane with morphologically well-preserved junctional feet structures.

Effects of maturation on multiscale (nanometer to millimeter) porosity in the Eagle Ford Shale

2015 ◽  
Vol 3 (3) ◽  
pp. SU59-SU70 ◽  
Author(s):  
Lawrence Michael Anovitz ◽  
David Robert Cole ◽  
Julia Meyer Sheets ◽  
Alexander Swift ◽  
Harold William Elston ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Pore Structure ◽  
Oil And Gas ◽  
Total Porosity ◽  
The United States ◽  
Total Surface Area ◽  
Eagle Ford Shale ◽  
Rock Composition ◽  
Eagle Ford ◽  
Gas Targets

Porosity and permeability are key variables that link the thermal-hydrologic, geomechanical, and geochemical behavior in rock systems and are thus important input parameters for transport models. Neutron scattering studies indicate that the scales of pore sizes in rocks extend over many orders of magnitude from nanometer-sized pores with huge amounts of total surface area to large open fracture systems (multiscale porosity). However, despite considerable efforts combining conventional petrophysics, neutron scattering, and electron microscopy, the quantitative nature of this porosity in tight gas shales, especially at smaller scales and over larger rock volumes, remains largely unknown. Nor is it well understood how pore networks are affected by regional variation in rock composition and properties, thermal changes across the oil window (maturity), and, most critically, hydraulic fracturing. To improve this understanding, we have used a combination of small- and ultrasmall-angle neutron scattering (U)SANS with scanning electron microscope (SEM)/backscattered electron imaging to analyze the pore structure of clay- and carbonate-rich samples of the Eagle Ford Shale. This formation is hydrocarbon rich, straddles the oil window, and is one of the most actively drilled oil and gas targets in the United States. Several important trends in the Eagle Ford rock pore structure have been identified using our approach. The (U)SANS results reflected the connected (effective) and unconnected porosity, as well as the volume occupied by organic material. The latter could be separated using total organic carbon data and, at all maturities, constituted a significant fraction of the apparent porosity. At lower maturities, the pore structure was strongly anisotropic. However, this decreased with increasing maturity, eventually disappearing entirely for carbonate-rich samples. In clay- and carbonate-rich samples, a significant reduction in total porosity occurred at (U)SANS scales, much of it during initial increases in maturity. This apparently contradicted SEM observations that showed increases in intraorganic porosity with increasing maturity. Organic-rich shales are, however, a very complex material from the point of view of scattering studies, and a more detailed analysis is needed to better understand these observations.

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