弱固结砂岩油藏出砂量预测模型

以固体变形和流体渗流为基础,将地层出砂简化成应力集中引起岩石破坏产生松散砂粒和流体流动使松散砂粒冲蚀运移这两个过程的耦合,并以孔隙度变化作为耦合基本参数,建立了出砂量预测的流固耦合模型,采用差分法进行了理论模型的数值求解。结果表明,随着地层破坏和连续出砂,井眼周围地层承受的应力重新分布,地层孔隙度和渗透率逐渐增加,产液量也逐渐增加。从预测出砂规律看,砂量在开始生产的几小时内先大幅度增加,达到一个峰值,然后逐渐降低并趋于一个稳定的低值。模拟结果与现场和室内观察现象一致,证明了该模型的可靠性。

Sand production modelling of weakly consolidated sand reservoir

Based on sand deformation and fluid seepage theory, sand production was simplified into two processes as rock failure and sand disgregation caused by stress concentration and sand transportation caused by fluid flow.Using porosity as coupling parameter,this paper established a hydro-geomechanical sand production prediction model based on the fluid flow and rock deformation framework.The model was solved numerically.Prediction results indicated that the stress around the borehole redistributed as rock failure and sand production,and the formation porosity and permeability gradually increased.Sand production increased to the highest value in a short time and then dropped to a low background value.The calculated results fit well with the field and laboratory observations,indicating the reliability of the model.