Recent application of Surface BOP from floating drilling rigs to drill offshore wells began in early 1996 in the relatively benign environments of Southeast Asia.
The techniques and equipment required to use surface blowout preventers from floating rigs have evolved progressively from the initial application in relatively shallow water benign environments using moored semisubmersible rigs to recent application in very deepwater moderate environments using dynamically positioned drilling rigs (Fig 1).
While much of the industry focus has been on developing floating surface bop deepwater applications, a significant number of wells have been drilled effectively in shallow water depths using Surface BOP drilling units. The appeal for utilizing floating drilling rig-based surface bop technology in these areas is that the technique can address a number of site-specific issues facing bottom-supported rigs. These include:
Bottom-supported rig site assessment issues related to soil conditions.
Risk mitigation associated with shallow geo-hazards.
Improved operational efficiency compared with conventional subsea BOP or bottom-supported rig alternatives.
Additionally availability of an economic alternative to bottom-supported units effectively expands the available rig fleet thereby mitigating possible rig availability project constraints.
In addition to providing viable alternatives to bottom-supported drilling units in certain shallow water circumstances, floating drilling rig-based surface BOP is more readily adapted to other emerging drilling methods than a conventional subsea BOP configuration.
This paper will:
Review current practice with respect to surface BOP application from floating drilling units.
Review alternative applications of surface BOP from floating drilling units
Introduce surface BOP from floating drilling units as an enabling technology for deploying emerging drilling methodologies and equipment.