基于柱坐标系的油井出砂三维数值模型设计与研究  

3-dimensional numerical model for sand production in oil wellbore based on cylindrical coordinate system

作　　者：刘先珊[1,2] 许明[1,2] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设与新技术教育部重点实验室(重庆大学),重庆400045

出　　处：《岩土工程学报》2013年第5期871-878,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51109231);重庆市自然科学基金项目(cstc2012jjA90005);武汉大学水资源与水电工程国家重点实验室开放基金项目(2012B100)

摘　　要：根据实际储层砂岩的物性和射孔试验特征,从岩土力学的角度基于柱坐标系建立三维颗粒流(PFC3D)数值模型。综合考虑流体压力梯度力和拖曳力产生的流固耦合效应,运用几何学方法研究油井出砂过程中的砂岩模型变化。数值计算与理论分析比较可知流体运动效应不可忽略,两者的应力分布曲线相吻合,验证了数值模型的可行性和适用性。另外,外界条件一定时,砂岩模型的应力分布、黏结颗粒性态、颗粒位移和流体对单颗粒作用力结果显示不同的单元划分对数值计算结果的影响不大,说明该数值模型的收敛性和稳定性。由此可见,提出的三维数值模型能较好地反映砂岩出砂过程中的宏细观力学特性,为准确理解砂岩出砂的力学机理提供了重要的研究思路和研究手段。Considering the properties of reservoir sand and the characteristics of perforation tests, a 3-dimensional particle flow code （PFC3D） model is established based on the cylindrical coordinate system from geo-mechanics perspective. Under the cylindrical coordinate system, the fluid-solid coupling theory considering pressure gradient force and drag force and the geometrical theory are adopted to study the change of the geometric model considering sand production in oil wellbore. Comparison between the numerical model and the analytical model indicates that the fluid flow should not be neglected for analysis of sand production, and the stress distribution is in coincidence for the above two methods, which verifies the feasibility and applicability of the proposed numerical model. In addition, under the given conditions, the results including the stress distribution, bonded particles, particle displacement and coupling force on the single particle indicate that different divisions of fluid cells have minor influence on the numerical simulation, which verifies the convergence and stability of this numerical model. Therefore, the proposed model can be used to simulate the macro-micro mechanical characteristics of sand production, and it provides an important technique to better reveal the mechanism of sand production.

关 键 词：柱坐标系 三维颗粒流数值模型 油井出砂 流固耦合 可行性 稳定性 

分 类 号：TU45[建筑科学—岩土工程]