DISCUSSIONS ON HOME MADE J-55 TUBING (NON UPSET THREAD) FAILURE

Tubing string failure often happens with the application of home made tubing being popularized in oil fields. It seriously influenced oil field normal production. The investigation result of 55 well accidents shows that there are four types of failure for newly used home made tubing. They are thread sticky, thread leakage, tubing body crack and other failures. The paper describes failure reason analysis of home made tubing(?73.3×5.51mm) based on the laboratory and field application test data. The analysis study includes tubing body quality, thread crease application, operation and abrasion in cluster wells. Then it pointed out that special care should be taken in operation for home made tubing in a way different from imported tubing, the supervision and quality control should be run in field operation. Besides new versions of API SPEC STD 5B and API SPEC 5TC standards should be obeyed when operator buys tubing product. Some additional technical requirements such as thread smoothness, hardness difference of tubing body and its joint, machine threads tightness in factory, physical and chemical properties and pressure test should be added according to practical needs of different oil field.