Modeling Technique Of Fractured Horizontal Shale Gas Wells With Complex Fracture Network And Its Application In Southern Sichuan

Deep shale gas is about to account for an increasing proportion in natural gas E&P and will be the main battlefield of shale gas reservoir development in the near future.Deep shale gas reservoir has the characteristics in terms of complexity of geological structure,strong heterogeneity,developed natural fracture,in-situ stress and complex artificial fracture network,which makes the characterization of complex fracture network of deep shale gas reservoir face great challenges.At present,although the embedded discrete fracture model and assisted history matching have been actively explored at home and abroad,and great progress has been made,less consideration has been given to the characterization of complex fracture boundary,dynamic history matching of inter well interference and low compuating efficiency.Therefore,this paper is committed to exploring a dynamic and static characterization method of complex fracture network in deep shale gas reservoir,which could be able to describe the boundary of complex fracture network successfully and characterize the production dynamic performance accurately.Meanwhile,the computing efficiency could be improved dramatically as well.Firstly,based on the edfm model,the static description model of fracture network suitable for the complex boundary of corner grid in deep shale gas reservoir is deduced.Simultaneously,the dynamic description method of complex fracture network which could be able to describe the inter-well interference is developed based on the Monte Carlo Markov Chain method based on the artificial intelligence proxy model such as XGBoost.Then,according to the EDFM based mesh generation,the finite difference method is implemented to numerically characterize the complex fracture network.On top of that,the dynamic and static integrated simulation computer program of complex fracture network of deep shale gas reservoir is created,and the feasibility of the model is verified.Finally,the dynamic and static integration model of complex fracture network of deep shale gas A platform in southern Sichuan is established by using the complex fracture network characterization method of deep shale gas reservoir proposed in this paper that combined with the dynamic and static data of existing wells.In addition,the interval of uncertain parameters such as effective fracture half length /fracture height ratio,effective fracture half length,effective fracture height and DRV /SRV ratio is quantified.Meanwhile,the productivity of the well platform is predicted and the feasibility of double-layer cubic well placement is demonstrated.Several conclusions are drawn through the research.First,the diamond fracture may reach the far-field area of the reservoir far away from the wellbore,which can realize more interection with the natural fracture DFN and unlock more areas.Second,natural fractures have an impact on inter-well interference,which makes the parent well have a significant impact on the performance of child wells,especially in the short-term production period.Third,the utilization of the type of "W" cubic well placement for exploiting deep shale gas in southern Sichuan could improve the profit of single shale gas well.The dynamic and static characterization method for describing complex fracture network of deep shale gas reservoir proposed in this paper provides a technical tool for formulating reasonable development technology policies for deep shale gas reservoir /well,and helps deep shale gas reservoir improve production,reduce cost,and realize economies of scale development.