摘要
在油田开采过程中,尤其是开采中后期,经常发生油井套管损坏现象,严重影响了油田的开发效益。引起油井套管损坏的因素很多,既有地质方面的,也有工程方面的。为了深入了解油井套管损坏的原因,以便采取有效措施保护套管,对地层的地质和井下工程情况进行了综合研究。首先,根据井筒中套管所受的应力场分布和作用机制,针对套管、水泥环、地层为弹性介质和塑性介质2种情况,分别建立了与之相对应的弹性和塑性数学物理模型及射孔后的流固耦合模型;然后,模拟计算分析了射孔、水泥环、地层岩性、注水压力、放喷流量、温度和压力等因素对套管受力的影响。结果表明:水泥环的弹性性质和厚度具有降低套管载荷的作用,地层的塑性和流变性对套管受力影响很大,地层压力的变化会引起套管应力的变化;可采取提高固井质量、确定射孔方向和选择合理的注水压力等措施来预防套管损坏。
Casing damage has been frequently occurring in the oilfield development process,especially in the late period of the development.Casing is damaged by various causes,including both geological and engineering factors.To understand the causes of casing damage,and to take effective measures to protect the casing,a comprehensive analysis is carried out on the formation geology and down-hole conditions.Firstly,the mathematical-physical models are established corresponding respectively to the elastic,plastic and fluid-solid coupling medium under the perforating conditions,by considering the combination of casing,cement and formation as an elastic or plastic medium.Secondly,a simulation analysis is conducted on the casing forces impact by perforating,cement and formation lithology and stresses.The cement elastic property and thickness may reduce the casing load.The formation plastic property and rheology have considerable influences on the casing stresses.The formation pressure changes may cause the changes of casing stresses.It might be possible to take some measurements to prevent the occurrence of casing damage,such as improving cementing quality,optimizing perforating direction,reasonable selecting injection pressure.
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2013年第4期94-98,101,共6页
Petroleum Geology and Recovery Efficiency
基金
国家基础研究"973"项目"深部油气储层综合地球物理探测和评价方法"(2013CB228605)
关键词
受力模型
数值模拟
套管损坏
弹塑性地层
地应力
水泥环
射孔
force model
numerical simulation
casing damage
elastic and plastic formation
stress
cement
perforate
