The Study On Mathematical Model And Numerical Simulation Of Productivity Of Multilateral Wells

Horizontal multilateral well is an efficient technology which can increase productivity of multilateral well and economic benefit.It will be the important technique in 21th century with the developments in petroleum field,after the technology of pinnate wells and horizonal wells are developed in 20th century. The theory od seepage flow in multilateral well was studied,but the theory of multilateral well in some special reservoir (as heavy oil reservoir) is not reported openly.In this thesis,productivity theory of multilateral well in recovery heavy oil ,reservoir with bottom water drive and so on is studied.The mathematical model and numerical model of multilateral well are developed and completed which the potential superposition principles is used considering pressure drop alone the horizontal wellbore(including well friction loss,acceleration pressure loss and mixture pressure loss).The numerical simulation is realized and the effects of formation parameters on the production rate of horizontal multilateral well are analyzed.The pressure and production of multilateral well in which anisotropy of stratum and pressure loss in wellbore are considered are studied.All this provide necessary theory basis and guidance scheme for the implement of this technology.Heavy oil always reveals non-newton rheological behaviors in formation and it can be viewed as power fluid.It follows the generalized Darcy's law.We set up a 3-d numerical model in which such factors as heterogeneity and anisotropy of stratum, permeability,and friction and acceleration loss in wellbore are considered.The numerical simulation is realized and programme is compiled.The production mechanism and unsteady dynamic analysis of multilateral wells and is analyzed based on numerical simulation.Production of multilateral well in different oil reservoir is studied.The effects of such formation parameters as permeability,thickness of reservoir,the length of side laterals on production rate of horizontal multilateral wells are analyzed.It provides necessary theory basis for the implement of this technology.The production of horizontal multilateral wells is high when the permeability ishigh,but it changes so much.The pressure in the wellbore is not the same for the pressure loss and it reduces the production of multilateral well;The production decreases with the time increases; the non-newton rheological behavior is the important factor to change the prodction .Stronger it is,the production is lower.