Petrophysical Evaluation of Organic Richness and Brittleness of Shale for Unconventional Hydrocarbon Prospecting: A Case Study on Vadaparru Shale, Krishna Godavari Basin, India
- Arijit Sahu (Oil and Natural Gas Corporation Ltd.) | Milan Kanti Das (Oil and Natural Gas Corporation Ltd.)
- Document ID
- Unconventional Resources Technology Conference
- SPE/AAPG/SEG Asia Pacific Unconventional Resources Technology Conference, 18-19 November, Brisbane, Australia
- Publication Date
- Document Type
- Conference Paper
- 2019, Unconventional Resources Technology Conference (URTeC)
- Shale organic richness, Poissonâ€™s ratio, Youngâ€™s modulus, TIV Brittleness
- 2 in the last 30 days
- 58 since 2007
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Shale has been a major destination for unconventional hydrocarbon resources for its wide stratigraphic coverage as well as high volumetric hydrocarbon potential. Contemporary success in North American shale plays has intrigued operators worldwide in shale exploration. Organic richness has been a key factor to determine the potential of shale as it is proportional to the amount of hydrocarbon likely to be generated and stored in available spaces within the shale. The other important factor in this context is shale brittleness as it indicates how fracable the potential shale is. Attempts are made here by strategically using standard wireline logs in order to evaluate potential of Eocene Vadaparru Shale in Krishna Godavari Basin, India qualitatively and quantitatively.
The technique used in this study involves identification of organic lean ‘clean shale’ interval and establishing a ‘clean shale’ relation of resistivity as a function of compressional sonic transit time in the study wells, as both the logs respond comparably to shale and its organic content. Using this relation a proxy ‘clean shale’ resistivity log is generated in shale and compared with measured wireline resistivity. A positive separation between calculated and measured resistivity is then assessed as proportionate shale organic richness, owing to the presence of relatively less dense (corresponding to longer sonic transit time) and more resistive organic content. Shale brittleness is predicted from Young's modulus and Poisson's ratio using compressional, shear and Stoneley wave velocities obtained from sonic measurements, assuming transversely isotropic nature of Vadaparru Shale.
The Eocene marine transgressive Vadaparru Shale is a dominant stratigraphy in KG basin as evident from seismics and drilling. Petrophysical analyses in study wells indicated appreciable brittleness within Vadaparru Shale. The organic richness i.e. amount of positive separation between calculated and measured resistivity combined with brittleness quantitatively indicate fair to excellent unconventional potential of Vadaparru Shale. Considerable thickness, Type-II, III kerogen content and geochemical measurements support the study and highlight it as a promising ‘shale reservoir’ destination. In the context of rapidly growing energy demand of India Vadaparru Shale can be considered as serious unconventional player.
Overall this study presents quick strategy for shale potential quantification, thus allowing operators to focus spatially in the quest of unconventional hydrocarbon resources.
|File Size||1 MB||Number of Pages||13|
Al-Qahtani, M. Y., & Zillur, R. (2001, January 1). A Mathematical Algorithm for Modeling Geomechanical Rock Properties of the Khuff and Pre-Khuff Reservoirs in Ghawar Field. Society of Petroleum Engineers. DOI:10.2118/68194-MS.
Grieser, W. V., & Bray, J. M. (2007, January 1). Identification of Production Potential in Unconventional Reservoirs. Society of Petroleum Engineers. DOI:10.2118/106623-MS.
Higgins, S. M., Goodwin, S. A., Donald, Bratton, T. R., & Tracy, G. W. (2008, January 1). Anisotropic Stress Models Improve Completion Design in the Baxter Shale. Society of Petroleum Engineers. DOI:10.2118/115736-MS
J. Tan.. Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity. Fuel 129 (2014) 204-218 http://dx.doi.org/10.1016/j.fuel.2014.03.064
Rickman, R., Mullen, M. J., Petre, J. E., Grieser, W. V., & Kundert, D. (2008, January 1). A Practical Use of Shale Petrophysics for Stimulation Design Optimization: All Shale Plays Are Not Clones of the Barnett Shale. Society of Petroleum Engineers. DOI:10.2118/115258-MS.
Sahu, A. (2018, March 20). Application of Integrated Compositional Gas Ratio Analysis to Understand Reservoir Hydrocarbon Potential and Enhance Confidence of Testing and Reservoir Lateral Drilling: With Examples from Krishna Godavari Basin, India. Offshore Technology Conference. DOI:10.4043/28594-MS.
Waters, G. A., Lewis, R. E., & Bentley, D. (2011, January 1). The Effect of Mechanical Properties Anisotropy in the Generation of Hydraulic Fractures in Organic Shales. Society of Petroleum Engineers. DOI:10.2118/146776-MS.
Zehnder, A. T. (2012), Fracture Mechanics, Springer, DOI: 10.1007/978-94-007-2595-9.