Fracturing of tight rocks during internal fluid production: implications for primary migration
Appears in the following Collection
- Fysisk institutt 
AbstractThis thesis presents a study of fracture formation in low permeability rocks induced by generation of fluid or gas during chemical reaction. In nature, primary migration of hydrocarbons, i.e. generation of oil and gas from tight source rock and its expulsion to more permeable reservoirs, is driven by formation of microfractures in the heated organic-rich shale. The tomographic 3D imaging of the rocks samples during heating showed that micro-cracks develop in the shale due to internal pore pressure build-up. Generation of hydrocarbons drives fracture formation until a drainage network sufficient for expulsion is developed. Experiments were also conducted on analogue material, where gelatine was fractured during fermentation of yeast and sugar. Studies of the gel confined in Hele-Shaw cell showed that CO2 generation leads to formation of a drainage network which topology represents a new class of networks, intermediate between hierarchical fracture pattern and river\tree network. When CO2 escapes via fracture network, individual cracks open and close in intermittent manner. The variation of fracture opening in time exhibits a universal frequency distribution with 1/f and 1/f2 noise. These results have implication for understanding how the generated fluids escape from hydraulic fractures. The methods can be applied in studying dehydration of sediments, formation of mud volcanoes, methane hydrate exploration and assessment, geological sequestration of carbon dioxide CO2, hydraulic fracturing of unconventional reservoirs, hydrothermal energy.
List of papers. Papers II and IV are removed from the thesis due to publisher restrictions.
Paper 1: 4D imaging of fracturing in organic-rich shales during heating. Maya Kobchenko, Hamed Panahi, Franois Renard, Dag K. Dysthe, Anders Malthe-Sørenssen, Adriano Mazzini, Julien Scheibert, Bjørn Jamtveit and Paul Meakin. Journal of geophysical research, Vol. 116, B12201, 2011. doi:10.1029/2011JB008565 Paper 2: A 4D synchrotron X-ray-tomography study of the formation of hydrocarbon- migration pathways in heated organic-rich shale. Hamed Panahi, Maya Kobchenko, Francois Renard, Adriano Mazzini, Julien Scheibert, Dag K. Dysthe, Bjørn Jamtveit, A. Malthe-Sørenssen and P. Meakin. Journal of Society of Petroleum Engineers, 18 (2): 366-377, SPE-162939-PA, 2013. doi:10.2118/162939-PA
Paper 3: Drainage fracture networks in elastic solids with internal fluid generation. Maya Kobchenko, Andreas Hafver, Espen Jettestuen, Olivier Galland, Francois Renard, Paul Meakin, Bjørn Jamtveit and Dag K. Dysthe. Draft version. Europhysics Letters, 102 66002, 2013. doi:10.1209/0295-5075/102/66002 Published by the EPLA under the terms of the Creative Commons Attribution 3.0 License (CC-BY).
Paper 4: Temporal evolution of a drainage fracture network in an elastic medium with internal fluid generation. Maya Kobchenko, Andreas Hafver, Espen Jettestuen, Olivier Galland, Francois Renard, Paul Meakin, Bjørn Jamtveit and Dag K. Dysthe. In preparation. Will be submitted to Physical Review E.
Paper 5: Porosity evolution and crystallization-driven fragmentation during weathering of andesite. Bjørn Jamtveit, Maya Kobchenko, Håkon Austrheim1, Anders Malthe-Sørenssen, Anja Røyne and Henrik Svensen. Journal of geophysical research, Vol. 116, B12204, 2011. doi:10.1029/2011JB008649