| Hydraulic fracturing technology is for the stripper wells to provide more capacity and an important means of recovery,but after having had hydraulic fracturing,the oil and gas wells for a variety of reasons may lead to hydraulic fracture failure in the production process,it is necessary for them to carry out re-fracturing,which has become an critical approach of increasing its output,ensuring stable oil field and enhancing economic efficiency.The new formation cracks developed owing to stress change in the course of repeated fracturing can open up new oil and gas flow road.These ones could enhance the effective scope of reservoir and conductivity ability,therefore,the new cracks analysis is extremely related to the effect of repeated fracturing.Based on repeated fracturing process induced by the stress field in the system,induced stress field model of re-fractured wells has been established through the research of primary artificial fracture,oil well production and the effect of added fiber on stress field before re-fracturing.The changeable rules of stress field could be known by analyzing some actual examples and calculation comparison.Whether the re-directed will take place or not can be known too.With the theory of rock mechanics,fracturing mechanics and hydraulic fracturing mechanics,the new cracks redirect,mechanism of creating new cracks,the best time for re-fracturing,the extension of new cracks have been researched further.Through the meshing of reservoir,associating fracture turning model with hydraulic fracturing two-dimension extending model,It can provide certain references for the next research of re-fracturing mechanism in complex reservoirs and guide for field analysis of re-fracturing in reservoirs. |
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