ENLIGHTENMENT OF CASING COLLAOSE IN WELL HAOKE 1 OF SHENGLI OIL FIELD

Well Haoke 1 is a research well to pursued large gas field in the lower deep zone underneath salt formation in Dongying depression of Shengli oil field. It has a design depth of 5000 m with EK2 as the target formation. The 244. 5 mm high strength SM-110T casing as intermediate casing was run in at 4324. 8 m to seal off the salt, gypsum and purple colored ooze zone with a thickness of 854. 5 m from 3395. 5 m to 4250 m. It was cemented on 12, May, l996 during trip out after cored drilling to 5476. 33 m with 215. 9 mm bit on 20, Feb.,1997, the pipe was stuck suddenly at 3945. 9 m, with casing deformation of 6. 48 mm and variation rate of 0. 72 mm/month. No oil showing was observed due to non target forma-tion drilled. It was determined to deepen the well with 200 mm bit. Pipe sticking occurred at 3759. 33 m while tripping out after drilled to 5807. 81 m on 30, May, the same year. It was freed through strong jarring and pulling up. It is estimated that 52d casing had a deformation of 15. 9 mm and a variation rate of 9. 17 mm/month. Later a 89 mm logging tool was run to check fhe casing’ The tool was stuck at 3850 m whilF pulling out. After unfrozen,a 152 mm bit was used to drift the well and had a tight point at 3594. 42 m, resulting in an early fin-ished operation. The casing deformation and several points of enlightenment are presented in the paper.