A diagnostic method for fracture network communication in shale gas wells
With the deepening of geological understanding of shale gas reservoir,three-dimensional development adjustment has become a common way to improve the utilization rate and recovery rate of shale gas reserves.Influenced by small well spacing,the development of natural fractures and the unequal utilization of old wells,fracturing interferences between three-dimensional shale gas development wells are inevitable and diverse,and the dynamic characteristics displayed by old wells are obviously different.Therefore,the diagnosis of fracture network communication based on production response is necessary.This paper takes the shale gas reservoir in Nanchuan work area as the research object,and uses hydraulic fracturing simulation and dynamic analysis of gas reservoir engineering to study the diagnostic method for fracture network communication in shale gas wells.The results show that:(1)According to the fracture conductivity,the fracture network communication mechanism of three-dimensional development wells can be represented by four communication forms of fracture network composed of natural fractures and fracturing fractures.(2)Responsing to different forms of fracture network communication,during the fracturing construction of three-dimensional development wells,the shut-in casing pressure of old wells presents four fluctuation forms,namely steady rise,rising fluctuation,slight fluctuation fall and violent fluctuation.The main controlling factors for casing pressure increase rate are the development degree of natural fractures,the inter-well recovery degree and the scale of new well strength transformation.(3)Combined with the change characteristics of production indexes after reproduction of old wells,decline rules and well testing curves etc.,a prediction table of fracturing interference fracture network communication of three-dimensional development wells in Nan-chuan work area is established.In field practice,the inter-well production interference or the fracture network communication can be predicted according to some charac-teristics in the prediction table,which provides scientific guidance for the fine numerical stimulation and optimization of segmented fracturing of three-dimensional development wells.
shale gas wellthree-dimensional developmentfracture network communicationdynamic responsefracturing inter-ferencenumerical simulation
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