A Study On The Basic Law Of Porous Flow Of Holes And Fractures

Fracture-vuggy reservoir space mainly includes two parts,the first part is fracture of different aperture,the second part is cave of different diameter.During the whole development of carbonate fracture-cavity reservoir,flood water breakthrough alone fracture,water content ratio increased fast,which results in the decline of production.Even worse,sudden water flooding may be serious,which increases the difficulty of stable oil production of fracture-vuggy reservoir.As the flow characteristics is not well knowned,and the flow mechanism of fluid is quite complicated,this paper is to explore the flow mechanism during displacement in flooding,learn the influence of several factors.So we take advantage of computational fluid mechanics,and get the optimization method.We designed and manufactured numerical fractured models and single fracture-vuggy model.Through the single numerical fracture model with different aperture,some water displacement simulation has been made under different circumstances.To explore the flow characteristics at different injection rate,and finally get the description of water displacement qualificatively and quantitatively.When horizontal displacement or vertical displacement,piston like displacement appeared when the injection rate is quite small.However,with the increasing of injecting rate,the initial piston like displacement transform into non-piston like displacement gradually.When erect displacing in numerical fracture model,there is an optimum velocity under which the oil recovery is the largest.Utilizing the single fracture-vuggy models,some dynamic displacement can be learned with injection at different rate.Furthermore,the numerical models can be placed horizontally,vertically and erectly,then more conclusion can be made.When the injection rate is quite small,water breakthrough time is long,the oil recovery increases little after water breakthrough;However,when the injection rate is big,water breakthrough time is small,water flooding or even jet-flow occurs,the oil recovery increases after water breakthrough.The research of comprehensive comparison between these displacement methods shows that vertical displacement makes the highest oil recovery.