Experiments on stress relaxation of the casing used in thermal recovery well
(0) The pre-stressed cementing technology for heavy oil thermal recovery wells has been adopted mostly at present.Through investigations,it is found that the wellheads of pre-stressed casing in thermal recovery wells with a depth less than 1000m are lifted greatly,which shows that the pre-stressed effect isnt obvious or doesnt play its proper role.In this paper,stress relaxation tests with two different kinds of N80 grade steel casing materials,which are commonly used for thermal recovery wells at 270℃,are carried out to find the stress relaxation phenomenon of the casing material.The experimental results show stress relaxation is very significant and its max.values can reach 46%.Meanwhile,the casing-cement-formation models are built up to discuss the effects of the constraints of wellhead,bottom,and deflecting section on pre-stresses of casing.Numerical simulations show the pre-stress is vanished in about 30 days,which is the main reason causing the uplifting of wellhead.Therefore,pre-stress is not recommended in the thermal recovery well with depth less than 1000m.
experiment thermal recovery well casing pre-stress relaxation
Jianjun Wang Yifei Yan Tongtao Wang Zhiqian Xu Lihong Han Xiangzhen Yan
College of Mechanical and Electronic Engineering,China University of Petroleum,Qingdao,China College of Pipeline and Civil Engineering,China University of Petroleum,Qingdao,China CNPC Tubular Goods Research Institute China National Petroleum Corporation Xian,China
国际会议
西安
英文
1-4
2012-10-01（万方平台首次上网日期，不代表论文的发表时间）