|
| |
Зарегистрирован: 31.12.69
|
|
Отправлено: 10.04.18 13:19. Заголовок: Effect of Pyrite on Total Organic Carbon Estimation
Incorporating the Effect of Pyrite on Total Organic Carbon Estimation in Eagle Ford Shale AuthorsShuxian Jiang (University of Louisiana at Lafayette) | Mehdi Mokhtari (University of Louisiana at Lafayette) | David M Borrok (University of Louisiana at Lafayette) DOIhttps://doi.org/10.2118/187484-MSDocument IDSPE-187484-MSPublisherSociety of Petroleum EngineersSource SPE Liquids-Rich Basins Conference - North America, 13-14 September, Midland, Texas, USA Publication Date2017 Show more detailView rights & permissions SPE Member Price: USD 8.50 SPE Non-Member Price: USD 25.00 Export citation Add to cart Ignoring the presence of pyrite can lead to errors in the estimation of Total Organic Carbon (TOC) since pyrite has significantly higher density and conductivity compared to other minerals in shale formations. This study aims to improve the accuracy of estimating TOC from well log data by accounting for the pyrite effect in Eagle Ford shale. To this end, more than 50 feet of preserved cores samples from the Eagle Ford were analyzed using laboratory pyrolysis, X-ray fluorescence (XRF), X-Ray Diffraction (XRD), and spectral core gamma system. Since there is significant vertical heterogeneity in the Eagle Ford shale, parameters such as TOC, pyrite content, Gamma ray intensity, content of Fe and S, and concentrations of U, Th, and K were analyzed on a fine scale in the Upper and Lower Eagle Ford respectively. Analysis of laboratory TOC data were applied to calibrate TOC data using geophysical well logs methodologies. Pyrite data from XRD analysis were used to find the relationship between pyrite and organic matter and to determine the effect of pyrite on well logs. Well-log-based TOC calculation methods were improved by considering pyrite as an adjustable parameter in equations. Schmoker's (1983) four-component system rock model and Alfred and Vernik's (2013) two-pore system model are two representatives of density-log-based TOC calculation methods. Based on these two models, a new petrophysical model considering pyrite and organic porosity was developed. In this research, empirical correlation between TOC and pyrite was explored. Changes of Fe and S concentrations with depth and Gamma ray intensity was determined. The trends of Fe sand S contents matched Gamma ray intensity very well in the depth range from 13790 ft to 13825 ft. Empirical relationships were found between TOC and Gamma ray intensity, TOC and Uranium, respectively. Furthermore, a new petrophysical model considering pyrite and organic porosity was validated with TOC and density data from shale formations. The proposed model improves the estimation of TOC calculation in Eagle Ford formation by the incorporation of pyrite effect. File Size 2 MB Number of Pages 14 Supporting information SUPPLEMENTARY/SPE-187484-SUP.pdf Alfred, D., Vernik, L., 2013. A new petrophysical model for organic shales, Petrophysics 54 (3): 240&-247. Alqahtani, A., Tutuncu, A., 2014. Quantification of Total Organic Carbon Content in Shale Source Rocks: An Eagle Ford Case Study. Unconventional Resources Technology Conference, 25-27 August, Denver, Colorado, USA Autric, A., Dumesnil, P., 1985. Resistivity radioactivity and sonic transit time logs to evaluate the organic content of low permeability rocks. The Log Analyst 26 (3): 37&-45. Berner, R.A., Raiswell, R., 1983. Burial of organic carbon and pyrite sulfur in sediments over Phanerozoic time: a new theory. Geochimica et Cosmochimica Acta, 47 (5): 855&-862. Beers, R.F., 1945. Radioactivity and organic content of some Paleozoic Shales. AAPG Bulletin 29 (1), 1&-22. Breyer, J.A., 2012. Shale reservoirs-Giant resources for the 21st century. AAPG Memoir 97. Decker, A.D., Hill, D.G., Wicks, D.E., 1993. Log-based gas content and resource estimates for the Antrim shale, Michigan Basin. SPE25910. In: Low Permeability Reservoirs Symposium. Denver, Colorado, USA. April 26&-28. Ellis, D.V., Singer, J.M., 2007. Well logging for earth scientists. Springer 2nd edition. Engel, M.H., Macko, S.A., 1993. Organic Geochemistry: Principles and Applications. Fertl, W. H., Chilingar, G.V., 1988. Total organic carbon determined from well logs. SPE Formation Evaluation 3 (02): 407&-419. Fertl, W. H., Rieke, H. H. 1980. Gamma ray spectral evaluation techniques identify fractured shale reservoirs and source-rock characteristics. Journal of Petroleum Technology 32 (11): 2053&-2062. Heidari, Z., Torres-Verdín, C., Preeg, W.E., 2011. Quantitative method for estimating total organic carbon and porosity, and for diagnosing mineral constituents from well logs in shale-gas formations. In: SPWLA 52nd Annual Logging Symposium, Colorado Springs, Colorado, USA, May 14&-18. Jarvie, D.M., Jarvie, B.M., Weldon, D., Maende, A., 2015. Geochemical assessment of in situ petroleum in unconventional resource systems. SPE178687. In: Unconventional Resources Technology Conference, San Antonio, Texas, July 20&-22. Kennedy, M., 2004. Gold fool's: detecting, quantifying and accounting for the effects of pyrite in modern logs. In: 45th SPWLA Annual Logging Symposium, Noordwijk, Netherlands, June 6&-9. Klimentos, T., 1995. Pyrite volume estimation by well log analysis and petrophysical studies. The Log Analyst 36 (06): 11&-17. Mahbobipour, H., Kamali, M.R., Solgi, A., 2016. Organic geochemistry and petroleum potential of Early Cretaceous Garau Formation in central part of Lurestan zone, northwest of Zagros, Iran. Marine and Petroleum Geology 77 (2016): 991&-1009. Martin, R., Baihly, J., Malpani R.et al. 2011. Understanding Production from Eagle Ford-Austin Chalk System, Presented at the SPE Annual Technical Conference and Exhibition, Denver, Colorado, 30 October-2 November. SPE-145117-MS. Meyer, B.L., Nederlof, M.H., 1984. Identification of source rocks on wireline logs by density/resistivity and sonic transit/resistivity crossplots. AAPG Bulletin 68 (2): 121&-129. Mendelzon, J.D., Toksoz, M.N., 1985. Source rock characterization using multivariate analysis of log data. In: SPWLA 26th Annual Logging Symposium. Dallas, Texas, USA, June 17&-20. Miles, 1994. Illustrated Glossary of Petroleum Geochemistry, Oxford University Press. Mullen, J. 2010. Petrophysical Characterization of the Eagle Ford Shale in South Texas. In: Canadian Unconventional Resources and International Petroleum Conference, Calgary, Alberta, Canada, October 19&-21. Passey, Q.R., Creaney, S., Kulla, J.B., Moretti, F.J., Stroud, J.D., 1990. Practical model for organic richness from porosity and resistivity logs. AAPG Bulletin 74 (12): 1777&-1794. Peters, K.E., 1986. Guidelines for evaluating petroleum source rock using programmed pyrolysis. AAPG Bulletin 70 (3): 318&-329. Schmoker, J. W. 1979. Determination of organic content of Appalachian Devonian shales from formation-density logs. AAPG Bulletin 63 (9):1504&-1537. Schmoker, J. W. 1981. Determination of organic-matter content of Appalachian Devonian shales from Gamma ray logs. AAPG Bulletin 65 (2): 1285&-1298. Schmoker, J., Hester, T., 1983. Organic carbon in Bakken formation, United States portion of Williston basin. AAPG Bulletin 67 (12): 2165&-2174. Shalaby, M.R., Hakimi, M.H., Abdullah, W.H., 2012. Organic geochemical characteristics and interpreted depositional environment of the Khatatba Formation, northern Western Desert, Egypt. AAPG Bulletin 96 (11): 2019&-2036. Shi, X., Wang, J., Liu, G., Ge, X.M., Jiang, X., 2016. Application of extreme learning machine and neural networks in total organic carbon content prediction in organic shale with wire line logs. Journal of Natural Gas Science and Engineering 33(2016):687&-702. Swanson, V.E., 1961. Geology and geochemistry of Uranium in marine black shales A review. Geological Survey Professional Paper 365-C: 67&-111. Wang, P.W., Chen, Z.H., Pang, X.Q., Hu, K.Z., Sun, M.L., Chen, X., 2016. Revised models for determining TOC in shale play: example from Devonian Duvernay shale, Western Canada sedimentary basin. Marine and Petroleum Geology 70 (2): 304&-319. Zhao, P.Q., Mao, Z.Q., Huang, Z.H., Zhang, C., 2016. A new method for estimating total organic carbon content from well logs, AAPG Bulletin 100 (8): 1311&-1327. Zhao, P.Q., Ma, H.L., Rasouli, V., Liu, W.H., Cai, J.C., Huang, Z.H., 2017. An improved model for estimating the TOC in shale formations, Marine and Petroleum Geology 83 (2017): 174&-183.
|