Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

Genty, Coralie; Jensen, Jerry L.; Ahr, Wayne M.

doi:10.1007/s11053-007-9035-8

Cited by 21 publications

(3 citation statements)

References 7 publications

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“…The Gaussian distribution function is used to fit the NMR T 2 distribution. The probability density function (PDF) of the Gaussian distribution is expressed as − where T 2 is the NMR transverse relaxation time expressed in ms, ∑ i = 1 n ω i = 1, 0 < ω i < 1 ( i = 1– n ), and ω i , μ i , and σ i are the i th weight coefficient, mean, and standard deviation, respectively.…”

Section: Methodsmentioning

confidence: 99%

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

et al. 2022

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The classification of tight sandstone reservoirs is of significance for hydrocarbon exploration and production. Different from conventional reservoirs, tight sandstone reservoirs are characterized by a complex pore structure and strong heterogeneity. Tight sandstone reservoir classification may not be reliable with conventional reservoir classification methods. In this paper, a classification method of tight sandstone reservoirs was proposed on the basis of the nuclear magnetic resonance (NMR) transverse relaxation (T 2 ) distribution, and it was employed for reservoir classification on the Shaximiao Formation in central Sichuan, China. As a result of the complex pore structure of a tight sandstone reservoir, the NMR T 2 distribution is characterized by the presence of multiple peaks. Therefore, the three-peak Gaussian function was used to fit the T 2 distribution and obtain the characteristic parameters. On the basis of high-pressure mercury intrusion (HPMI) experiments, the correlation between the characteristic parameters of the NMR T 2 distribution and pore structure parameters and petrophysical properties was analyzed, and then the optimal characteristic parameters of the NMR T 2 distribution were selected according to the results of correlation analysis and used to establish the pore structure index. In combination of petrophysical properties with the pore structure index, the model for classification of tight sandstone reservoirs was established by the naive Bayesian method based on hierarchical clustering, and the accuracy of the model was verified by k-fold cross-validation. Finally, the effectiveness of the proposed method was verified using the actual NMR logging data in conjunction with the oil test data. The results showed that the method for classification of tight sandstone reservoirs based on the NMR T 2 distribution can provide effective guidance for production capacity evaluation.

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Section: Methodsmentioning

confidence: 99%

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

et al. 2022

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“…Hiroaki Izumiuama [6~8] et al studied the influence of freeze-melting cycles on the porosity of granite, sandstone and other rocks and established a damage extension model of different weathered bedrock types. Coralie Genty and Jerry L, Jensen [9] et al greatly improved the success rate of identifying rock pore types with complex internal structures by splitting 2 T into three Gaussian components and classifying the pore types using Bayesian methods. Zhu [10] conducted a digital test of the uniaxial compression deformation damage of marble samples and analyzed the evolution laws of microcracks; Li Jielin and Zhu Longyun [11] studied the influence laws of pore water on sandstone pore changes under freeze-melting cycles.…”

Section: Introductionmentioning

confidence: 99%

Study on Mesoscopic Stuctural Damage and Permeability Evolution of Freeze-Thaw Shale

Wang

Xuan

Jin

et al. 2021

Preprint

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To study the mesoscopic damage and permeability evolution of rock under freezing-thawing (F-T) cycles, freezing-thawing cycle experiments were carried out on shale under different F-T temperatures and cycles, and nuclear magnetic resonance (NMR) and permeability experiments were conducted on shale after F-T. On the basis of the experiment, the pores and permeability of the F-T shale are analyzed, and the existing permeability model is modified and improved; Therefore, the mesoscopic damage evolution characteristics and permeability evolution law of the F-T shale are obtained. It is found that with the increase in the number of cycles, the pore structure of the rock samples changes as the pore size expands and the number of pores increases, and the average porosity also increases correspondingly. It is also found that there is a good positive correlation between the increase in shale porosity and the increase in permeability. Therefore, it is believed that the increase in pore size and pore number leads to an increase in porosity, which in turn leads to an increase in permeability. On the basis of the improved SDR permeability model, the spectral area ratio parameters of large pores and fractures in the T2 spectrum were added for correction, and the number of the F-T cycles and temperature parameters were introduced to obtain the modified permeability evolution model of F-T shale. Compared with the experimental results, it is found that the modified model has good applicability. The damage law and permeability of shale under different F-T conditions are analyzed from the microscopic point of view, which has important reference significance for engineering construction in frozen soil areas.

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“…(2004) used a trimodal Weibull distribution to fit nuclear magnetic resonance (NMR) T 2 spectra, which is closely correlated to the pore-body size distribution when the rock is fully water saturated. Similarly, Genty et al (2007) (Spencer, 1963;Nimmo, 2004…”

Section: Introductionmentioning

confidence: 99%

Geophysics Dissertation Abstracts

2013

GEOPHYSICS

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GEOPHYSICS publishes abstracts of dissertations and titles of master's theses both in print and online. Recent graduates are invited to submit their abstracts or titles by completing and submitting the appropriate form found at http://seg.org/ dissertationabstracts. Abstracts and titles will be reviewed and accepted or rejected based on their relevance to the readers of Geophysics. Abstracts must be written in English and defended in 2009 or later.Reservoir description with well-log-based and core-calibrated petrophysical rock classification Chicheng Xu, The University of Texas at Austin Month and year defended: July 2013Bimodal log-normal pore-size distribution functions derived from mercury injection capillary pressure (MICP) data are first introduced to characterize complex pore systems in carbonate and tight-gas sandstone reservoirs. Six pore-system attributes are interpreted and integrated to define petrophysical orthogonality or dissimilarity between two pore systems. A simple 3D cubic pore network model constrained by nuclear magnetic resonance (NMR) and MICP data is developed to quantify fluid distributions and phase connectivity for predicting saturation-dependent relative permeability during two-phase drainage.There is rich petrophysical information in spatial fluid distributions resulting from vertical fluid flow on a geologic time scale and radial mud-filtrate invasion on a drilling time scale. Log attributes elicited by such fluid distributions are captured to quantify dynamic reservoir petrophysical properties and define reservoir flow capacity thereby. A new rock classification workflow that reconciles reservoir saturation-height behavior and mud-filtrate for more accurate dynamic reservoir modeling is developed and verified in both clastic and carbonate fields.Rock types vary and mix at the sub-foot scale in heterogeneous reservoirs due to depositional control or diagenetic overprints. Conventional well logs are limited in their ability to probe the details of each individual bed or rock type as seen from outcrops or cores. A bottom-up Bayesian rock typing method is developed to efficiently test multiple working hypotheses against well logs to quantify uncertainty of rock types and their associated petrophysical properties in thinly bedded reservoirs. Concomitantly, a top-down reservoir description workflow is implemented to characterize intermixed or hybrid rock classes from flow-unit scale (or seismic scale) down to the pore scale based on a multiscale orthogonal rock class decomposition approach.Correlations between petrophysical rock types and geologic facies in reservoirs originating from deltaic and turbidite depositional systems are investigated in detail. Emphasis is placed on the cause-and-effect relationship between pore geometry and rock geologic attributes such as grain size and bed thickness. Well-log responses to those geologic attributes and associated pore geometries are subjected to numerical log simulations. Sensitivity of various physical logs to petrophysical orthogonality betw...

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Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

Cited by 21 publications

References 7 publications

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

Study on Mesoscopic Stuctural Damage and Permeability Evolution of Freeze-Thaw Shale

Geophysics Dissertation Abstracts

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Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

Cited by 21 publications

References 7 publications

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T2 Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T2 Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

Study on Mesoscopic Stuctural Damage and Permeability Evolution of Freeze-Thaw Shale

Geophysics Dissertation Abstracts

Contact Info

Product

Resources

About

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China

Classification of Tight Sandstone Reservoirs Based on the Nuclear Magnetic Resonance T₂ Distribution: A Case Study on the Shaximiao Formation in Central Sichuan, China