Determination of Total Organic Carbon Content in Shale Formations With Regression Analysis

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Jianguo Wang ◽  
Daihong Gu ◽  
Wei Guo ◽  
Haijie Zhang ◽  
Daoyong Yang
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Gamma Ray ◽  
Relative Difference ◽  
Absolute Difference ◽  
Organic Carbon Content ◽  
Shale Formations ◽  
The Difference ◽  
T Distribution

By correcting both the positive and negative ΔlogR separation resulting from the resistivity in organic-deficient shales, the traditional ΔlogR correlation is modified, validated, and applied to determine the total organic carbon (TOC) content in shale formations. The TOC content is determined once the Fisher distribution, which represents the significance of each model, and Student's t-distribution, which denotes the significance of every variable in the models, have achieved values equal to or higher than their respective threshold values at a confidence level of 95%. Using a total of 45 sets of logging measurements, the newly proposed correlation is found to be able to reproduce the measured TOC values with a root mean-squared absolute difference (RMSAD) of 0.30 wt % and root mean-squared relative difference (RMSRD) of 23.8%, respectively. Uranium concentration, apart from interval transit time and resistivity, is found to be key in determining the TOC content in organic-rich shale without other radioactive minerals. By combining the reading of DGR (i.e., the difference between the spectral gamma ray with the radioactivity and the computed gamma ray without uranium), the traditional ΔlogR technique has now been improved and extended to the negative ΔlogR separation resulting from the resistivity in organic-deficient shale higher than that in organic-rich shale.

Greenschist-facies metamorphism of the Burgess Shale and its implications for models of fossil formation and preservation

2003 ◽  
Vol 40 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Wayne Powell
Keyword(s):  
Organic Carbon ◽  
Greenschist Facies ◽  
Organic Carbon Content ◽  
Canadian Rocky Mountains ◽  
Burgess Shale ◽  
Rock Composition ◽  
Shale Formations ◽  
Metamorphic History ◽  
Crenulation Cleavage

Metamorphosed silty mudstones of the Burgess Shale and Stephen Shale formations record a poly metamorphic history. An early greenschist-facies event associated with burial by Paleozoic strata produced a nearly ubiquitous bedding-parallel cleavage (S1). Tectonic exhumation during the formation of the southern Canadian Rocky Mountains produced a domainal subgreenschist-facies retrograde overprint in which a high-angle crenulation cleavage (S2) was developed. Whereas all rocks have experienced these two events, the degree of deformation and fossil pre servation varies with position relative to the Cathedral Escarpment. This paleosubmarine cliff resulted in a zone of reduced deformation within adjacent strata by buttressing them during burial and deflecting deformation during orogenesis. Fossil-bearing strata are composed of a typical greenschist assemblage of muscovite–chlorite–quartz–albite, are devoid of clays, and contain an average of 0.28% organic carbon. This typical metamudstone assemblage is consistent with the typical whole-rock composition of these rocks which tends to be richer in K and Al and poorer in Fe relative to the Post-Archean Average Shale. These mineralogical–compositional characteristics suggest that the premetamorphic clay assemblage was likely illite–smectite–kaolinite, with no evidence of highly reactive species such as nontronite or Na-montmorillonite. This is contrary to the required conditions for taphonomic models involving organic preservation due to clay-related suppression of decomposition-related reactions. Metamorphism of the Burgess Shale has also re duced the total organic carbon content to <20% of initial values. This must be considered in any models that involve interpretation of organic carbon in diagenetic processes (e.g., fossil formation and determination of paleoredox conditions).

A novel method for determining the internal recycled dust load in kraft recovery boilers

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 27-34
Author(s):  
MATHEUS ANTUNES GUIMARÃES ◽  
HONGHI TRAN ◽  
MARCELO CARDOSO
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Black Liquor ◽  
Organic Carbon Content ◽  
Kraft Recovery Boilers ◽  
Recovery Boilers ◽  
Boiler Operation ◽  
Novel Method ◽  
The Difference ◽  
Dust Load

In kraft recovery boiler operation, fly ash or dust generated from black liquor combustion is mixed with the virgin black liquor in a mix tank and returned to the boiler with the as-fired black liquor. This internal recycled dust stream varies widely from boiler to boiler and from time to time and can have a great impact on the as-fired black liquor flow and properties and, ultimately, on the boiler thermal performance. A new method has been developed to quickly and accurately determine the amount of internal recycled dust in recovery boilers. The method is based on the difference between the total organic carbon content of the virgin black liquor and that of the as-fired black liquor. Tests using the method were performed on recovery boilers at three of Fibria’s mills in Brazil. The results show that while the specific virgin black liquor solids produced at these mills were about the same, the internal recycled dust load varied widely, from as low as 4 wt% of as-fired black liquor solids fired in the boiler at one mill to as high as 15 wt% at another mill. Instead of total organic carbon values, heating values may also be used, but the result is not as accurate.

scholarly journals Dual-shale-content method for total organic carbon content evaluation from wireline logs in organic shale

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Nie ◽  
Yu Wan ◽  
Fan Bie
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Gamma Ray ◽  
Rock Physics ◽  
Organic Carbon Content ◽  
Statistical Regression ◽  
Digital Rock Physics ◽  
Response Characteristics ◽  
Physics Experiment ◽  
Organic Shale

AbstractOrganic shale is one of the most important unconventional resources all around the world. Total organic carbon (TOC) content is an important evaluation parameter of reservoir hydrocarbon source quality. The regular evaluation methods have higher requirements of well logs and core experiment data for statistical regression. Through analyzing the resistivity and gamma ray logging response characteristics of shale content and organic matters, combined with digital rock physics experiment simulation, we put forward and improve the dual-shale-content method for TOC content logging evaluation. The accuracy of this method is verified by actual data processing. The result shows the dual-shale-content method is simple to use and the error is small. And by comparing with the calculation results by using the

scholarly journals Relationship between Color CIEL∗a∗b∗ and Total Organic Carbon in Compost

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Jhon Jairo Palechor-Tróchez ◽  
Luis Eduardo Ordoñez Santos ◽  
Hector Samuel Villada-Castillo
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Carbon Content ◽  
Total Organic Carbon Content ◽  
Organic Carbon Content ◽  
Particle Sizes ◽  
Surface Color ◽  
Total Organic Carbon Concentration ◽  
Organic Carbon Concentration ◽  
Pearson Correlations

The CIEL∗a∗b∗ coordinates and the total organic carbon content in compost were correlated. Two particle sizes of 0.5 and 2 mm were obtained in the compost samples; the surface color was analyzed with a CIEL∗a∗b∗ colorimeter and the total organic carbon content by spectrophotometry at 588.9 nm. The results indicate that all chromaticity values were significantly affected (p<0.001) by particle size. Chromaticity values a∗, b∗, C∗, and h° showed significantly strong Pearson correlations (r>0.95). The coordinates a∗ (r=−0.992) and b∗ (r=0.968) have the potential to be used in estimating the total organic carbon concentration in the compost samples analyzed.

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