Improved Decision Making During Drilling Operations: Using a Wireline Coring System, Offshore Brazil

Abstract The Corion ™ Express coring system was used Offs coring programs. The Wireline system offers an efficient way to trip core while maintaining a large diameter core necessary to achieve high recovery rates and high quality cores. It also allows the operator to quickly decide as whether or not to simply drill ahead or to retrieve additional cores without additional trips in and out of the well. The coring/drilling assembly has been designed to either drill ahead in a conventional fashion or to core while drilling ahead. The Corion Express cored the entire 3- ENC-2 reservoir interval and then deployed the drilling insert to TD the well without tripping the Drill String. 3 ½" cores of unconsolidated sand were recovered to surface conveyed by wire line through the ID of specialized drill pipe and BHA. At the completion of coring, and confirming the presence of the base formation, the drilling insert was deployed through the drill string and BHA via wire line, latched into place and the drilling to TD was completed. This technology has the capability to provide the operator with a step level change in the acquisition of high quality cores in a more cost effective fashion. By eliminating trips the tool becomes very cost effective for long interval or multiple interval coring programs. The major advantage over existing technologies is the large diameter of the core head. The significance lies not only in larger diameter core capable of replacing conventional coring, but also in the fact that logging tools may be lowered through the bit and into the open well bore. The flexibility of a tool that offers coring, drilling, and open hole logging without tripping pipe can have a significant impact on exploration programs.