Study On The Application Of Expandable Convoluted Tubing Technique In Well Drilling

Drilling is getting harder and harder with the development of exploration and the increase in deep and ultra deep well exploitation. Especially when drilling through the complex formations such as low pressures and leak layer, the casing is usually used to heal and strength and increase casing layers, because it is easy for casing program design ,increase pipe layers will lead to the well hole too small, and it will make it harder for next work, maybe the well is given up for unable to drill the aim layer, some although can drill to the aim layer, but the well hole is too small to develop and repair the well and increase the production. It has been a problem of drilling deep well and ultra deep well, which prevent deep well and ultra deep well technique from improving. Oil workers are always looking for a better way to drill to the aim layer well and effectively, the most idea way is drilling with the same diameter bit , and well completion with the same diameter case, the expandable convoluted tubing technique is just the first step to realize this goal. Now the expandable casings using in drilling engineering include expandable tabular and expandable convoluted tubing.The paper research the expandable convoluted tubing. On the basis of complex and compared analysis between abroad technique, the whole structure type is made, select the end surface construction,connection way and the power analysis is done to the pressure and expand process of the expandable convoluted tubing.The indoor experiment plan and device mating was finished for the expandable convoluted tubing, multifunction drilling experiment staging was built, experiment was done to the expandable convoluted tubing, such as resist civil press, resist outside crush,welding examination, expandable tool experiment, complex simulation experiment. It proves that the resist civil press strength of the expandable convoluted tubing reach to 35 MPa, resist outside crush strength reach to 10 MPa, the performance reach and exceed the same kinds in abroad. It fills the requirement for the construction sites.On the based of most experiment data, The way is made for expandable convoluted tubing and the related device research was done, select the tool for extend the hole. The leak and loss circulation control experiment was succeeded in 15-19 well in Jiangshu oil field, which proved the develop potential of this technique.