The Quantitative Analysis of Optimized Pressure Drawdown in Unconsolidated Sand Reservoirs

Abstract

Sand production is a serious problem in unconsolidated sandstone, it's becomes more critical as operators follow more aggressive production strategies. A successful sand control or management needed to evaluate sand production probability, to quantify risk reduction, and to establish practical operational scheme for safe and optimum production.In this paper, focusing on the coupling between fluid flow and solid deformation, a consistent geometrical frame for sand prediction is established, which includes the capacity to predict sand production onset, sand quantities and sand production rates. Finite element method is used to solve the coupled governing equation system. Field data for sand production and enhanced oil production from Bohai Oilfield (Tianjin, China) were used to validate the model for the sand rate and sand production. Our studies indicate that the optimized pressure drawdown in unconsolidated sand be controlled by the following key physical parameters: (1) rock strength; (2) fluid viscosity; (3) pressure drawdown build-up strategy and pressure disturbance. The simulation results relating cumulative sand production and sand production rate to these important variables are presented.The study suggests that the proposed model may be used to generate quantitative information for predicting sand production and optimizing pressure drawdown. This provides a tool for sand-management in exploiting the weakness of sanding-prone scenarios.