盐膏层造斜井段井眼缩径及套管外载数值模拟

盐膏层是油气成藏的良好盖层，塔里木盆地多个大型油气藏都属于巨厚盐下油气藏，为了提高单井产能，决定采用定向井和水平井来开发盐下油气藏。由于盐膏层距离产层较近，需要在盐膏层进行造斜。造斜井段盐膏层井眼的缩径规律及其对套管外载的影响国内外鲜有报道。应用有限元方法建立了造斜井段砂岩和盐膏岩地层、水泥环及套管耦合的三维力学模型，以塔里木羊塔克区块岩石力学测试成果为基础，研究得到造斜段井斜和方位对井眼缩径及套管外载的影响规律。该研究成果成功应用于塔里木巨厚盐下定向井、水平井轨迹设计，钻遇盐膏层泥浆密度的确定和井身结构设计，为塔里木盐膏层钻井、完井施工提供了重要的理论参考。

Numerical simulation of wellbore shrinkage and casing load in build-up section in salt rock

Salt rock is good for reservoir forming as cap rock.Many reservoirs in Tarim basin are buried deeply underground in salt rock,drilling directional well to exploit reservoirs in salt rock will enhance recovery of single well.As the distance between salt layers and production layer is close,so the build-up process will be in salt layers;but the laws of wellbore shrinkage in build-up section in salt layers and effects on casing external load are little reported.So,a 3-D salt rock-cement mantle-casing coupling mechanical model is established.On the basis of rock mechanics test of Yangtake in Tarim,the effect laws of deviation angle and azimuth angle on wellbore shrinkage and casing external load are researched.Research results have been used to guide trajectory design,mud density design and casing program design for direction wells in Tarim,and lay a solid theoretical basis for well drilling and completion in salt rock in Tarim oil field.