Casing Milling
SPE INTERNATIONAL
Abstract
Sidetracking has been proven to be a cost saving solution over drilling new horizontal wells to increase production from existing wells. Most problems that might be encountered when removing casing can be identified prior to beginning a lining removal job. By identifying these potential problems, the proper equipment can be used effectively to keep the job running smoothly. Technical advances in mill design such as the development of a cutting structure that effectively manages the cuttings size and is more wear resistant has increased the efficiency of the entire operation.
Introduction
A cost effective means to enhance production and provide for reservoir stimulation from existing platforms is to sidetrack wells from existing slots to reach new bottom hole locations. In the process of recovering these slots to facilitate the sidetrack, one or more casing strings must e removed from the existing well. Casing removal is accomplished by a combination of process such as cutting, pulling and milling. In typical wells 13 3/8” and 9 5/8” casing is cut and pulled from the well. Liners from 5 ½” through 9 5.8” may be milled to facilitate their removal.
Liners and casing cemented to the surface require removal by milling long intervals which have historically been slow and at best, time consuming process. Numerous operational problems exist including difficulty in cuttings removal and potentially stuck string from “bird-nesting” of cuttings. With new technology available, these problems can be eliminated or minimized to make liner removal a low risk economical choice for slot recovery.
This paper describes the process for recovering these platform slots and provides a review of new technology that enhances the economics of the process. Case studies will show how proper selection of the BHA, mud and mud handling system, mill design, and milling parameters make slot recovery and liner removal fast and economical. Many of the
Abstract
Sidetracking has been proven to be a cost saving solution over drilling new horizontal wells to increase production from existing wells. Most problems that might be encountered when removing casing can be identified prior to beginning a lining removal job. By identifying these potential problems, the proper equipment can be used effectively to keep the job running smoothly. Technical advances in mill design such as the development of a cutting structure that effectively manages the cuttings size and is more wear resistant has increased the efficiency of the entire operation.
Introduction
A cost effective means to enhance production and provide for reservoir stimulation from existing platforms is to sidetrack wells from existing slots to reach new bottom hole locations. In the process of recovering these slots to facilitate the sidetrack, one or more casing strings must e removed from the existing well. Casing removal is accomplished by a combination of process such as cutting, pulling and milling. In typical wells 13 3/8” and 9 5/8” casing is cut and pulled from the well. Liners from 5 ½” through 9 5.8” may be milled to facilitate their removal.
Liners and casing cemented to the surface require removal by milling long intervals which have historically been slow and at best, time consuming process. Numerous operational problems exist including difficulty in cuttings removal and potentially stuck string from “bird-nesting” of cuttings. With new technology available, these problems can be eliminated or minimized to make liner removal a low risk economical choice for slot recovery.
This paper describes the process for recovering these platform slots and provides a review of new technology that enhances the economics of the process. Case studies will show how proper selection of the BHA, mud and mud handling system, mill design, and milling parameters make slot recovery and liner removal fast and economical. Many of the