Formation Mechanism For Artificial Fracture Network In The Tight Oil Reservoirs Of Ji Yuan Oil Field

Because of the low permeability and the poor supply ability from the matrix to fracture,it's hard to achieve the expected stimulation effect only on the traditional hydraulic fracturing.In order to increase initial productivity and ultimate recovery rate,we must choose the volume fracturing to reform reservoir.This technology can expand the flow area by forming an artificial fracture network.But the current research on the formation mechanism of artificial fracture network is not sufficient,so study about the formation of complex fracture network by tight oil volume fracturing is necessary.In response to this situation,this paper takes Jiyuan block Yanchang tight oil reservoirs for example.Based on the comprehensive understanding of reserviors' characteristics,the paper analyses and evaluates the volume fracture effect,thus summarizes the application characteristics of volume fracture in Jiyuan block.Meanwhile,physical model of indoor experiments for recognizing rock mechanics properties and natural fracture development situation in tight oil reservoir shows that geological conditions may effect the formation of artificial fracture network.And the paper proposes engineering conditions of forming artificial fracture network by volume fracture parameters in field tests.Through these studies,there will be two kinds of situations when hydraulic fractures intersect with natural fractures:passing through natural fractures,or extending along the maximum horizontal stress direction with the formation of secondary cracks,thus forming a complex fracture network.Shear,slip and dislocation behaviors within fracture are related to the net pressure.Spindle-shaped and dumbbell-shaped fracture network are the best for oil flowing.