Abstract
The economic success of shale gas plays depends expansively on the brittle-ductile behavior of shale rock for effective hydraulic fracturing. Successful hydraulic fracturing requires targeting the most brittle rocks. Therefore it is worthwhile to classify the shale regarding brittle and ductile zones. To study the impact of brittleness indices in the brittle-ductile transitional zone, we have estimated the mineralogy-based brittleness index, TOC (total organic carbon), pore pressure and geomechanical properties from well logs and core description laboratory measurements. The petrophysical model of Sembar shale from Indus basin Pakistan was compared to brittleness index, organic contents, and pore pressure to differentiate the transitional zones in shale gas reservoirs. The result shows that constant change in rock minerals distribution and brittleness index follow the trend in TOC content, in brittle- ductile and transitional zone. Also, the data was plotted in λρ-μρ lithology templates and plots of Young’s modulus and Poisson’s ratio, shale with high quartz and clay contents trap in less ductile to less brittle zone while shale with abundant quartz and low clay contents give rise in the brittle zone. The observations of this study support the previous research idea by suggesting the zones of brittle and transition controlled by TOC to design the hydraulic fracture more efficient.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Alassi, H.T., Holt, R.O., Nes, M., and Pradhan, S., 2011, Realistic geomechanical modeling of hydraulic fracturing in fractured reservoir rock. Canadian Unconventional Resources Conference, Calgary, Nov. 15–17, SPE-149375-MS.
Bowers G.L., 2001, Determining an appropriate pore-pressure estimation strategy. Annual Offshore Technology Conference (OTC 13042), Houston, April 30–May 3, p. 921–934.
Bai, M., 2016, Why are brittleness and fracability not equivalent in designing hydraulic fracturing in tight shale gas reservoirs. Petroleum 2 (2016), Southwest Petroleum University, 1–19.
Carpentier, B., Hue, A.Y., and Bessereau, G., 1991, Wireline logging and source rocks estimation of organic carbon content by the Carbolog method. The Log Analyst, 32, 279–297.
Eaton, B.A., 1972, The effect of overburden stress on geopressures prediction from well logs. Journal of Petroleum Technology, 24, SPE-3719-PA. https://doi.org/10.2118/3719-PA
Gee, E.R., 1989, Overview of the geology and structure of the salt range with observations on related areas of northern Pakistan in Malinconico: Tectonics of the western Himalayas. Geological Society of America, Special Paper, 232, 95–112.
Grieser, B. and Bray, J., 2007, Identification of production potential in unconventional reservoirs. Production and Operations Symposium of Society of Petroleum Engineering (SPE), Oklahoma City, March 31–April 3, SPE-106623-MS.
Goodway, B., Chen, T., and Downton, J., 1997, Improved AVO fluid detection and lithology discrimination using Lamé petrophysical parameters: “λρ”, “μρ”, & “λ/μ fluid stack” from P and S inversions. 67th Annual International Meeting of Society of Exploration Geophysicist, (SEG technical program Expanded Abstract), Dallas, Nov. 2–7, p. 183–186.
Hucka, V. and Das, B., 1974, Brittleness determination of rocks by different methods. International Journal of Rock Mechanics and Mining Sciences, 11, 389–392.
Jarvie, D., Hill, M.R.J., Ruble, T.E., and Pollastro, R.M., 2007, Unconventional shale-gas systems: The Mississippian Barnett shale of north-central Texas as one model for thermogenic shale-gas assessment. American Association of Petroleum Geologists Bulletin, 91, 475–499.
Jaeger, J.C. and Cook, N.G., 1979, Fundamentals of rock mechanics. Springer, 585 p.
Khalid, P., Qayyum, F., and Yasin, Q., 2014, Data-driven sequence stratigraphy of the Cretaceous depositional system, Punjab Platform, Pakistan. Surveys in Geophysics, 35, 1065–1088.
Liang, C., Jiang, Z., Cao, Y., Wu, M., Ling, G., and Zhang, C., 2016, Deepwater depositional mechanisms and significance for unconventional hydrocarbon exploration: a case study from the lower Silurian Longmaxi shale in the southeastern Sichuan Basin. American Association of Petroleum Geologists Bulletin, 100, 773–794.
Li, Z., Fangyan, H., Xinwei, H., Wan, L.Z., and Yuting, H., 2014, Shalegas reservoir-prediction study in Daanzhai, eastern Sichuan basin. The Leading Edge, 33, 526–534.
Liu, H.H., Ranjith, P.G., Georgi, D.T., and Lai, B.T., 2016, Some key technical issues in modelling of gas transport process in shales: a review. Geomechanics and Geophysics for Geo-Energy and Geo- Resources. DOI 10.1007/s40948-016-0031-5
Nazir, A., Javed, M., Kashif, S., Nasar, M., and Fahad, A., 2012, Shale gas Potential of lower Cretaceous Sembar formation in middle and lower Indus basin, Pakistan. Pakistan Journal of Hydrocarbon Research, 22, 51–62.
Paterson, M.S. and Wong, T., 2005, Experimental rock deformation-the brittle field (2nd edition). Springer, Berlin, 347 p.
Perez, M., 2011, Developing templates for integrating quantitative geophysics and hydraulic fracture completions data: Part 1–Principles and theory. 81th Annual Meeting of Society of Exploration Geophysicist (Expanded Abstracts), San Antonio, Sept. 18–23, p. 1794–1798.
Perez, R. and Marfurt, 2013, Calibration of Brittleness to elastic rock properties via mineralogy logs in unconventional reservoirs. International Conference and Exhibition of American Association of Petroleum Geologists (AAPG), Cartagena, Sept. 8–11, Article #41237.
Robinson, C.R., Smith, M.A., and Royle, R.A., 1999, Organic facies in Cretaceous and Jurassic hydrocarbon source rocks, southern Indus Basin, Pakistan. International Journal of Coal Geology, 39, 205–225.
Rybacki, E., Reinicke, A., Meier, T., Makasi, M., and Dresen, G., 2015, What controls the mechanical properties of shale rocks? Part 1–Strength and Young’s modulus. Journal of Petroleum Science and Engineering, 135, 702–722.
Rickman, R.M., Mullen, E., Petre, B.G., and Kundert, D., 2008, A practical use of shale petrophysics for stimulation design optimization: All shale plays are not clones of the Barnett shale. Annual Technical Conference and Exhibition of Society of Petroleum Engineers, Denver, Sept. 21–24, SPE-115258-MS.
Singh, P., 2008, Lithofacies and sequence stratigraphic framework of the Barnett Shale. Ph.D. Thesis, University of Oklahoma, Norman, 181 p.
Shah, S.M.I., 1980, Stratigraphy and economic geology of central salt range. Records of the Geological Survey of Pakistan, 52, 104 p.
Van, D.P., Papanastasiou, C.J., and Pater, D., 2000, Impact of rock plasticity on hydraulic fracture propagation and closure. Annual Technical Conference and Exhibition of Society of Petroleum Engineering, Dallas, Oct. 1–4, SPE-63172-MS.
Wang, F.P. and Gale, J.F.W., 2009, Screening criteria for shale-gas systems. Gulf Coast Association of Geological Societies Transactions, 59, 779–793.
Yang, Y., Sone, H., Hows, A., and Zoback, M.D., 2013, Comparison of brittleness indices in organic-rich shale formations. 47th United State Rock Mechanics/Geomechanics Symposium, San Francisco, June 23–26, ARMA-2013-403.
Yangjian, O., 1995, Interpretation of well-logging and description of reservoir rock. The Petroleum Industry Press, China, p. 54–109.
Zhu, Y., Enru, L., Alex, M., Michael, A.P., and Christopher, E.H., 2011, Understanding geophysical responses of shale-gas plays. The Leading Edge, 30, 332–338.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Yasin, Q., Du, Q., Sohail, G.M. et al. Impact of organic contents and brittleness indices to differentiate the brittle-ductile transitional zone in shale gas reservoir. Geosci J 21, 779–789 (2017). https://doi.org/10.1007/s12303-017-0007-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12303-017-0007-7