Abstract
This paper discusses specialized completion tools and techniques developed while drilling and completing the open hole sections of 20 horizontal gravel packs and 3 Level 5 multi-lateral wells completed in Campos Basin, offshore Brazil. The discussion covers wellpath planning, pumping operations, wellpath selection, multilterals, the use of extended-longevity well screens, floating rig operations, and fluid systems to prevent formation damage.
Open hole horizontal wells are attractive in ultra-deep water because the approach eliminates a liner and allows a larger casing string at the reservoir. This method also provides extensive reservoir exposure. Couple this technology with multi-laterals and a significant reduction in the number of wells to adequately drain the reservoir may be achieved.
Twenty open hole completions have been successfully performed in the deepwater Marlim field offshore Brazil. These include both gravel- and non-gravel-packed completions in horizontal producers and injectors. Additionally, three Level 5 multi-lateral wells with open hole completions have been successfully installed in the same field.
Multi-lateral (ML) completions have been classified as Levels 1 through 6, depending upon junction functionality. Only Levels 5 and 6 pertain to this discussion. Only Levels 5 and 6 provide pressure integrity at the junction. Level 5, a cased and cemented main bore and laterals, achieves pressure isolation at the junction with packers. Level 6 is similar to Level 5 except that pressure isolation at the junction is achieved using the casing.
