@article{2-s2.0-85077470990,

title = {Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems},

author = { P.C. Hackley and C.V. Araujo and A.G. Borrego and A. Bouzinos and B.J. Cardott and H. Carvajal-Ortiz and M.R. López Cely and V. Chabalala and P.J. Crosdale and T.D. Demchuk and C.F. Eble and D. Flores and A. Furmann and T. Gentzis and P.A. Gonçalves and C. Guvad and M. Hámor-Vidó and I. Jelonek and M.N. Johnston and T. Juliao-Lemus and S. Kalaitzidis and W.R. Knowles and J. Kus and Z. Li and G. Macleod and M. Mastalerz and T.R. Menezes and S. Ocubalidet and R. Orban and W. Pickel and P. Ranasinghe and J. Ribeiro and O.P. Gómez Rojas and R. Ruiz-Monroy and J.S. Schmidt and A. Seyedolali and G. Siavalas and I. Suárez-Ruiz and C.V. Vargas and B.J. Valentine and N.J. Wagner and B. Wrolson and J.E. Jaramillo Zapata},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077470990&doi=10.1016%2fj.marpetgeo.2019.104172&partnerID=40&md5=54b9bdcba5174f1fcac4c519faae175a},

doi = {10.1016/j.marpetgeo.2019.104172},

issn = {02648172},

year  = {2020},

date = {2020-01-01},

journal = {Marine and Petroleum Geology},

volume = {114},

publisher = {Elsevier Ltd},

abstract = {An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (Tmax >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes < 100 nm) via SEM suggests that intraparticle organic nano-pores are most abundant in dry gas maturity samples and less abundant at lower wet gas/condensate and peak oil maturities. Samples were distributed to ILS participants in forty laboratories in the Americas, Europe, Africa and Australia; thirty-seven independent sets of results were received. Mean vitrinite reflectance (VRo) values from all ILS participants range from 0.90 to 1.83% whereas mean solid bitumen reflectance (BRo) values range from 0.85 to 2.04% (no outlying values excluded), confirming the thermally mature nature of all six samples. Using multiple statistical approaches to eliminate outlying values, we evaluated reproducibility limit R, the maximum difference between valid mean reflectance results obtained on the same sample by different operators in different laboratories using different instruments. Removal of outlying values where the individual signed multiple of standard deviation was >1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VRo or BRo) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems. © 2019},

note = {14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-85018441649,

title = {Identification of alginite and bituminite in rocks other than coal. 2006, 2009, and 2011 round robin exercises of the ICCP Identification of Dispersed Organic Matter Working Group},

author = { J. Kus and C.V. Araujo and A.G. Borrego and D. Flores and P.C. Hackley and M. Hámor-Vidó and S. Kalaitzidis and C.J. Kommeren and B. Kwiecińska and M. Mastalerz and J.G. Mendonça Filho and T.R. Menezes and M. Misz-Kennan and G.J. Nowak and H.I. Petersen and D. Rallakis and I. Suárez-Ruiz and I. Sýkorová and D. Životić},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018441649&doi=10.1016%2fj.coal.2017.04.013&partnerID=40&md5=08d4ff4dd09a1b9e1233746df0afcfa2},

doi = {10.1016/j.coal.2017.04.013},

issn = {01665162},

year  = {2017},

date = {2017-01-01},

journal = {International Journal of Coal Geology},

volume = {178},

pages = {26-38},

publisher = {Elsevier B.V.},

abstract = {The paper presents results of round robin exercises on photomicrograph-based identification of dispersed organic matter in source rocks that represent a range of marine and lacustrine deposits from worldwide localities and cover a range of thermal maturities. The round robin exercises were conducted by the Identification of Dispersed Organic Matter Working Group (IDOM WG) of the International Committee for Coal and Organic Petrology (ICCP). The round robin exercises aimed to (1) assess the applicability of the established ICCP definitions of bituminite, (2) identify deficiencies and improve the existing nomenclatures, and (3) provide a basis for the revision of the bituminite and alginite definitions in the ICCP Handbook (Taylor et al.; 1998). Three round robin exercises performed in 2006, 2009 and 2011 involved 18 participants from research laboratories at universities and within government and industry. Participants were asked to identify macerals on the basis of existing definitions in 129 photomicrographs taken in incident white light and fluorescent mode and also in fluorescence light mode at prolonged (15 min) blue light irradiation. The results indicate that the definition of telalginite permits its positive and satisfactory agreement among the participants. In contrast, the descriptive characteristics of lamalginite referring to film-like appearance (filamentous) and lack of inner or outer structure are insufficient and inadequate to enable an unequivocal discrimination between it and telalginite. Furthermore, based on the amorphous nature of bituminite and lack of adherence to its established description and character (Taylor et al.; 1998), the highest discrepancies were observed in its identification. Differentiation of bituminite from a fluorescent groundmass and in some cases from lamalginite proved to be particularly challenging. The findings of these round robin exercises are useful for improving the identification of sedimentary organic matter in source rocks and may be an important foundation for the modification of the ICCP definitions of alginite and bituminite. © 2017 Elsevier B.V.},

note = {26},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-84906222841,

title = {Standardization of reflectance measurements in dispersed organic matter: Results of an exercise to improve interlaboratory agreement},

author = { P.C. Hackley and C.V. Araujo and A.G. Borrego and A. Bouzinos and B.J. Cardott and A.C. Cook and C.F. Eble and D. Flores and T. Gentzis and P.A. Gonçalves and J.G. Mendonça Filho and M. Hámor-Vidó and I. Jelonek and K. Kommeren and W.R. Knowles and J. Kus and M. Mastalerz and T.R. Menezes and J. Newman and I.K. Oikonomopoulos and M. Pawlewicz and W. Pickel and J. Potter and P. Ranasinghe and H. Read and J. Reyes and G.D.L. Rosa Rodriguez and I.V. Alves Fernandes de Souza and I. Suárez-Ruiz and I. Sýkorová and B.J. Valentine},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906222841&doi=10.1016%2fj.marpetgeo.2014.07.015&partnerID=40&md5=706065637b6795157db0f7458b850d09},

doi = {10.1016/j.marpetgeo.2014.07.015},

issn = {02648172},

year  = {2015},

date = {2015-01-01},

journal = {Marine and Petroleum Geology},

volume = {59},

pages = {22-34},

publisher = {Elsevier Ltd},

abstract = {Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the D7708 measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (0.31-1.53% Ro), from organic-lean to organic-rich (1-22wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability limits (maximum difference between valid repetitive results from same operator; same conditions) ranged from 0.03 to 0.11% absolute reflectance, whereas reproducibility limits (maximum difference between valid results obtained on same test material by different operators; different laboratories) ranged from 0.12 to 0.54% absolute reflectance. Repeatability and reproducibility limits degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping the other components. Discussion among participants suggested this problem could not be easily corrected via kerogen concentration or solvent extraction and is related to operator training and background. No statistical difference in mean reflectance was identified between participants reporting bitumen reflectance vs. vitrinite reflectance vs. a mixture of bitumen and vitrinite reflectance values, suggesting empirical conversion schemes should be treated with caution. Analysis of reproducibility limits obtained during this exercise in comparison to reproducibility limits from historical interlaboratory exercises suggests use of a common methodology (D7708) improves interlaboratory precision. Future work will investigate opportunities to improve reproducibility in high maturity, organic-lean shale varieties. © 2014 Elsevier Ltd.},

note = {121},

keywords = {},

pubstate = {published},

tppubtype = {article}

}