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Crack propagation and hydraulic fracturing in different lithologies
- Source :
- Applied Geophysics. 16:243-251
- Publication Year :
- 2019
- Publisher :
- Springer Science and Business Media LLC, 2019.
-
Abstract
- We simulated hydraulic fracturing in different lithologic rocks in the horizontal drilling by using the true physical model experiment and large rock specimens, carried out the real-time dynamic monitoring with adding tracer and then did post-fracturing cutting and so on. Based on this monitoring results, we compared and assessed the factors affecting expansion in shale, shell limestone, and tight sandstone and the fracture expansion in these rocks. In shale, the reformed reservoir volume is the highest, fracture network is formed in the process of fracturing. In tight sandstone, the fracture surface boundaries are curved, and the fracture surface area accounts for 25–50% of the entire specimen. In shell limestone, the complexity of the fracture morphology is between shale and tight sandstone, but no fracture network is developed. Brittleness controls the fracture surface area. In highly brittle rocks, the fracture surface area is high. Fracture toughness mainly affects the initiation and propagation of cracks. A fracture network is formed only if bedding planes are present and are more weaker than their corresponding matrix. The horizontal in situ deviatoric stress affects the crack propagation direction, and different lithologies have different horizontal in situ deviatoric stress thresholds. Low fluid injection rate facilitates the formation of complex cracks, whereas high fluid injection rate favors the development of fractures. Fluid injection weakly controls the complexity of hydraulic fracturing in low-brittleness rocks, whereas low-viscosity fracturing fluids favor the formation of complex cracks owing to easy enter microcracks and micro-pore. Displacement has a greater impact on high brittle rocks than low brittle rocks.
- Subjects :
- 010504 meteorology & atmospheric sciences
Fracture mechanics
010502 geochemistry & geophysics
01 natural sciences
Matrix (geology)
Geophysics
Fracture toughness
Hydraulic fracturing
Brittleness
Bed
Rock mechanics
Fracture (geology)
Petrology
Geology
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 19930658 and 16727975
- Volume :
- 16
- Database :
- OpenAIRE
- Journal :
- Applied Geophysics
- Accession number :
- edsair.doi...........5f85354d8b64817e4f28c54c0a0885d9
- Full Text :
- https://doi.org/10.1007/s11770-019-0764-3