Study On Mechanism Of Wellbore Fracture Re-orientation During Refracturing Of Glutenite Reservoir

For glutenite reservoir,fractures that created by the initial stimulation treatment can easily fail because of the wrong fracturing design and variety geologic factors,which lead to the production depress.Aimed at this kind of well,re-fracturing treatment is necessary.The key factors of wellbore fracture redirection technique are guideness effect of oriented perforating and the induced stress generated before re-fracturing,which can generate reoriented fracture and gain wider stimulated reservoir volume.In this paper,plenty of methods were used to study the mechanism of wellbore fracture redirection technique and the fracture propagation affected by gravels from the glutenite reservoir,such as formula development,numerical stimulation and experiments.Firstly,the calculation method of induced stress generated by initial fracture and well production was given through plasto elasticity and Biot fluid-solid coupling formula development,as well as the impact of induced stress to the refracturing reoriented radius.Then the model of induced stress caused by oriented perforating has been given,as well as the influence of perforating factor on refracturing twisting with a 3D finite element model of the near wellbore area.A model of infiltration flow-stress-damage coupling has been established to study how mechanic properties,shape factors of gravel and engineering factors effect fracture track,as well as gravel content in glutenite reservoir.Finally,a triaxiality stress hydraulic fracturing experiments have been carried out to identify preceding theoretical study results.the study result of this paper can be used to optimize glutenite reservoir refracturing design in field.