The Study On Horizontal Wellbore Acidizing Simulation In Sandstone Reservoir

It is different between horizontal well and vertical well, such as damage characterization, acidizing mechanism and treatment technology. Special research must be done for matrix acidizing of horizontal well. After studying some mechanism of acidizing ,such as acid-rock reaction mechanism, wormhole generation in acidizing, pore structure of sandstone reservoir, we propose a numerical model for matrix acidizing of horizontal well.Exposed time and permeability anisotropy are considered as factors causing non-uniform fluid invasion in horizontal wells.The proposed model includes fluid invasion, filter cake build up, and relative permeability components. Filter cake and mud filtration models were developed based on a mass balance equation of cake deposition and erosion and Darcy's equation. A convection-dispersion equation was solved numerically to characterize filtrate invasion.truncated elliptical cone with the larger base near the vertical section of the well.It is the first time to propose fluid placement model by the way of reservoir/horizontal well coupling method, which can apply for different reservoir, take into account the effects of frictional pressure drops. Especially, which can simulate the acid placement under normal injection way. The conclusions show that A.D.hill and Frick model have some mistakes.A mathematical model that describes chemical reactions of reactive fluids in composite reservoirs has been developed for predicting concentration profiles of acid solution, which can simulate the reaction of 3-D space. The result of simulation can directively be applied for models calculating the productivity of a horizontal well, which can predict the productivity after acidizing treatment.Semianalytical model is presented to predicting performance of horizontal wells, some parameters is tested for the effects of production, such as well diameter, flow rate, pressure drop in well etc. The result shows that distribution of flux and pressure is not uniform. Local damage will make local flux is small, the production of heel become small because of irregular distribution of damage.At the same time, a numerical model is presented for coupling wellbore and reservoir, which can simulate 3D, multiphase flow, it can also simulate transient...