RIASSUNTO
Abstract
This paper describes development and testing of a new guide shoe mill (GSM) for intervention fishing services in conjunction with the well construction’s drilling hazard mitigation. Primary application of this mill is for milling guide-shoe left in the well by the solid expandable running tool system. The traditional milling direction is downwards. The new mill was designed to mill upwards in the reverse direction, thereby clearing the restriction and restoring the well bore casing drift internal diameter (ID). This paper covers development of guide shoe mill, failure analysis on a test well, and improvements done in various steps to prevent future failures. Use of Finite Element Analysis (FEA) models and extensive lab tests are also discussed.
The ability to maintain stabilization while milling in a high vibration environment and to remove cuttings to the surface were two major challenges. The guide shoe mill out tool provides stability, efficient well cleaning to restore casing drift ID, thus saving on non-productive time (NPT) and other drilling related costs. The study of failure prevention has lead to better technology applications and process improvements. Successful results obtained from lab testing (including test rig) lead to potential application in other areas such as selective section casing patch removal.