A new method for predicting the limit liquid production rate of oil well based on fluid-solid coupling

The liquid increasing of oil well is one important measure to stabilize the production when an oilfield steps into the period of high water cut. Speaking of the conventional limit liquid production capacity study, its key point is only confined to the discrimination of energy supply capacity and limit production pressure difference, and its prediction on the limit liquid increasing capacity is mainly by means of the Darcy linear method. It is assumed that the porous medium where the fluid flows in the reservoir is rigid and the reservoir permeability is constant. Unconsolidated sandstone reservoirs of high porosity, high permeability and poor consolidation are widely distributed in the offshore oilfields of the Bohai Bay. These reservoir characteristics and liquid increasing method lead to elastic and plastic deformation, skeleton deformation and sand production of the porous medium where the fluid flows, which result in the essential transformation of the percolation conditions, so the error of the conventional limit liquid production capacity prediction method is large. After firstly dissecting the conventional limit liquid production capacity study, this paper theoretically analyzed the influence factors and change laws of porous medium. Then, combined with the oilfield production practice data, the change laws were introduced into the percolation theory to infer the liquid production capacity prediction method based on fluid-solid coupling. This prediction method is applied in Bohai C Oilfield. And compared with the actual oilfield data, the error rate of the fitting result is only 5% and the fitting rate is 40%-50% higher than that of conventional method. Therefore, this prediction method is worth popularizing.