高压气藏地层三维出砂预测模型及方法  

Three-dimensional model and procedures for prediction of sand production in gas reservoirs

作　　者：张广清[1] 陈勉[1] 金衍[1] 

机构地区：[1]石油大学石油天然气工程学院,北京102249

出　　处：《岩土工程学报》2005年第2期198-201,共4页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金资助项目(50274054)

摘　　要：根据有效应力定律和气体非线性达西定律,建立了应力场和压力场相互作用的三维弹塑性高压气藏地层出砂模型,并运用弹塑性有限元方法进行求解。根据编制的计算程序,研究了射孔井筒附近有效塑性应变、压力和流速的分布规律:最大有效塑性应变位置是在射孔起始部位的上下端;稳定后的压力由远至井筒呈不规则漏斗状,并且气体流速急剧增加,最大值位置是射孔底部。高压气藏地层出砂是由受压力影响的有效应力场控制的,而由于气体的压力敏感性造成的流速急剧增加是出砂的重要诱因。地层压力越高临界生产压力越低,因而越不易出砂。对于高压气藏地层,尽量稳定井底生产压力、保持合理的生产压差、维持较高的地层压力、采用合理的气井工作制度,有助于减小出砂量。Based on the principle of effective stress and nonlinear Darcy's law for gas, three-dimensional elasto-plastic model for sand production with coupled stress and pressure is established, which is solved by the nonlinear finite element method. According to results obtained with the numerical code, distributions of effective plastic strain, pressure, and velocity are investigated. The maximum effective strain occurs at the top and bottom of the starting position of perforations; the stable pressure looks like irregular funnel, and the gas velocity increases dramatically with the its maximum value occurring at the end of perforations. From the distributions of effective plastic strain and velocity, sand production in gas reservoirs is controlled by the effective stress; and steep increase in gas velocity due to pressure dependency is the important affecting factor. Meanwhile, high formation pressure will reduce the possibility of sand production. For gas reservoirs with high pressure, to maintain high formation pressure, to stabilize the bottom hole pressure and to keep this pressure below the limit value would help to reduce the amount of sand production.

关 键 词：高压气藏 三维出砂模型 气固耦合 弹塑性有限元 

分 类 号：TE358[石油与天然气工程—油气田开发工程]