科研之友
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摘要
Cased and perforated horizontal wells are always used in hydraulic fracturing to stimulate unconventional reservoirs, and the fracture initiation pressure (FIP) is of great importance for the choice of fracturing equipment and scheme. Many methods have been employed to fulfill this requirement. Usually, in conventional methods, the analysis of stress distribution near the wellbore is simplified by overlooking the influence of excavation process of the wellbore and perforations, which might cause the inaccuracy of stress analysis in the near-wellbore region. In many works, the application of maximum tensile stress (MTS) criterion in predicting FIP is extended from open wells to geometrically complex wells, but has been demonstrated to be not highly accurate in certain cases. In this paper, a staged finite element model approach is used to obtain the stress distribution around a horizontal wellbore and perforations. In addition, a simplified rock post-failure constitutive model is employed to trace fracture development and help make better prediction of FIP. Compared with conventional methods, the simulation results of the new model are more practical in stress analysis of near-wellbore region and effective in capturing the potential main hydraulic fracture, which is vital for a reasonable FIP prediction. The effectiveness of the new model is verified by the field data and physical experiment results.
- 出版日期2017-7
- 单位中国石油大学（北京）
