Abstract: 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.

Key words: salt rock, wellbore shrinkage, casing, external load, numerical simulation