The Optimized Allocation Between Well Pattern Infilling And Hydraulic Fracture Of Ansai Chang6Reservoir

As the AnSai Chang6ultra-low permeability reservoir enters the middle and laterperiods, large injection-production spacing and unreasonable hydraulic fracture parameterscan lead to less effective or ineffective oil well, and new well floodout because of improperfracturing scale and uncertain fracture azimuth, the development effect is not ideal. Accordingto the current problems, a series of researches with an emphasis on the well pattern infillingand the matching relationship of fracture parameters to secondary well net should beconducted. Therefore, based on the former research, this paper studys the reasonable patterninfilling method and the allocation relationship between hydraulic fracture and well pattern.First demonstrate the feasibility of well pattern infilling by reservoir engineering method.Then typical concept models of AnSai Chang6reservoir are built using numerical simulationtechnology to analyze remaining oil reservoir distribution rule, finally, the reasonable patterninfilling methods are determined. On this basis, the local stress field of infill well and thepossibility of fracture reorientation are discussed. Based on the best fracture parameters of theoriginal oil well, especial researches on the allocation relationship between infill well fractureand secondary well net are carried on. The result shows that when reverse square nine-spotwell pattern is used in reservoir with no fracture, remaining oil distribution existing betweeninjectors and producers shows a triangle shape, between producers and producers shows stripshape, the best infilling adjustment method is diagonal encryption. According to thedifferent influence law of converted producers to infill wells, infill wells are divided into A、Btwo kinds of well, the best fracture length and the best fracture conductivity are givenrespectively of two types of well at the different steering angle. The reverse rhombusnine-spot well pattern is used in fracture reservoir, the greater natural fracture grows, thegreater hydraulic fracture length and conductivity of the fracture directional wells, the moreobvious of water flooding advantage direction and the worse development effect will be, stripshape remaining oil enriches in the fracture lateral, the best infilling adjustment method islateral multiple encryption. Affected by natural fracture, it is little possibility of fracturereorientation, the best fracture length and fracture conductivity is50m,200~250×10-3μm2·m. Finally, take the WangYao、Sai160oil field as example, infilling adjustment program isobtained based on the research result, practicality and effectiveness of the theoretical study isconducted. The result provides theoretical references to well pattern infilling and theoptimization of infill well fracture parameters for the middle and later periods oflow-permeability reservoir.