Petroleum Science >2015, Issue 4: 628-635 DOI: https://doi.org/10.1007/s12182-015-0048-3
Stress redistribution in multi-stage hydraulic fracturingof horizontal wells in shales Open Access
文章信息
作者：Yi-Jin Zeng,Xu Zhang and Bao-Ping Zhang
作者单位：
Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China;Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China;Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China
投稿时间：2015-05-11
引用方式：Zeng, YJ., Zhang, X. & Zhang, BP. Pet. Sci. (2015) 12: 628. https://doi.org/10.1007/s12182-015-0048-3
文章摘要
Multi-stage hydraulic fracturing of horizontal
wells is the main stimulation method in recovering gas
from tight shale gas reservoirs, and stage spacing determination
is one of the key issues in fracturing design. The
initiation and propagation of hydraulic fractures will cause
stress redistribution and may activate natural fractures in
the reservoir. Due to the limitation of the analytical method
in calculation of induced stresses, we propose a numerical
method, which incorporates the interaction of hydraulic
fractures and the wellbore, and analyzes the stress distribution
in the reservoir under different stage spacing.
Simulation results indicate the following: (1) The induced
stress was overestimated from the analytical method
because it did not take into account the interaction between
hydraulic fractures and the horizontal wellbore. (2) The
hydraulic fracture had a considerable effect on the redistribution
of stresses in the direction of the horizontal
wellbore in the reservoir. The stress in the direction perpendicular
to the horizontal wellbore after hydraulic fracturing
had a minor change compared with the original
in situ stress. (3) Stress interferences among fractures were
greatly connected with the stage spacing and the distance
from the wellbore. When the fracture length was 200 m,
and the stage spacing was 50 m, the stress redistribution
due to stage fracturing may divert the original stress pattern,
which might activate natural fractures so as to
generate a complex fracture network.
wells is the main stimulation method in recovering gas
from tight shale gas reservoirs, and stage spacing determination
is one of the key issues in fracturing design. The
initiation and propagation of hydraulic fractures will cause
stress redistribution and may activate natural fractures in
the reservoir. Due to the limitation of the analytical method
in calculation of induced stresses, we propose a numerical
method, which incorporates the interaction of hydraulic
fractures and the wellbore, and analyzes the stress distribution
in the reservoir under different stage spacing.
Simulation results indicate the following: (1) The induced
stress was overestimated from the analytical method
because it did not take into account the interaction between
hydraulic fractures and the horizontal wellbore. (2) The
hydraulic fracture had a considerable effect on the redistribution
of stresses in the direction of the horizontal
wellbore in the reservoir. The stress in the direction perpendicular
to the horizontal wellbore after hydraulic fracturing
had a minor change compared with the original
in situ stress. (3) Stress interferences among fractures were
greatly connected with the stage spacing and the distance
from the wellbore. When the fracture length was 200 m,
and the stage spacing was 50 m, the stress redistribution
due to stage fracturing may divert the original stress pattern,
which might activate natural fractures so as to
generate a complex fracture network.
关键词
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Shale gas Horizontal well Multi-stagefracturing Complex fracture Stage spacing Inducedstress