Theoretical Study On Linear Composite Seepage In Horizontal Wells Of Fracture-cavity Reservoirs

Carbonate reservoirs play a very important role in the world's gas and oil resources.Because carbonate reservoir is usually with strong anisotropy,a horizontal well drilled in it may extends through a compartmentalized reservoir which consists of different formations and conventional well test models are inapplicable.It's necessary for us to build up new models to satisfy the need of well test.Through the domestic and foreign literature investigation,the well test method that a horizontal well extends through a multi-zone reservoir is studied on the basis of the accumulation of forefathers' research.Different kinds of physical and mathematical models are established and solved by using the point source function,Green function and coupling of multiple reservoir blocks.The type curves are obtained by computer and sensibilities analysis are carried on.In this paper,the works accomplished are:(1)Through the domestic and foreign literature investigation about the flow mechanics of fractured-vuggy reservoir and the well test theory and analysis of horizontal well,the current situation of well test development is analyzed;(2)According to the different combination of natural fracture,cave and matrix in carbonate reservoir,this paper devides this type of reservoir into two model for research:dual-medium model and triple-medium model.The flow mechanics of naturally fractured carbonate reservoir is discussed simultaneously;(3)The point source function in a rectangular parallelepiped reservoir is put forward,and its solutions are obtained.Under the condition of infinite-conductivity in the wellbore,multi-zone homogenous model is established and solved by using the Green function and coupling of multiple reservoir blocks.The type curves are obtained and sensibilities analysis are carried on at the same time;(4)For dual porosity(fracture-matrix)reservoir,considering the process of the pseudo-steady interporosity flow of matrix to fracture,multi-zone dual porosity model is established and solved by using the point source function,Green function and coupling of multiple reservoir blocks.The type curves are obtained and sensibilities analysis are carried on simultaneously;(5)For triple porosity(fracture-matrix-vug)reservoir,considering the process of the pseudo-steady interporosity flows of matrix to fracture and vug to fracture,multi-zone triple porosity model is established and solved by using the point source function,Green function and coupling of multiple reservoir blocks.The type curves are obtained and sensibilities analysis are carried on simultaneously.