In traditional drilling, each stand to be drilled down requires a pre-installed sub. When the stand is drilled, the sub is used to create an access point to the drill string.
The Non-Stop Driller™ (NSD) system uses a high-pressure mud hose with an integrated quick connect mechanism and an HMI-controlled remote manifold to redirect the flow path of drilling mud through the side entry value in the NSD sub. Closing the ball valve at the top of the side entry value isolates drill string pressure, allowing constant circulation during connections.
When the connection is completed, the flow of drilling mud is redirected through the top drive and drilling continues with the NSD sub, which is now an integral part of the drill string downhole.
The Non-Stop Driller™ system features fully actuated values controlled by a dedicated HMI system incorporating multiple safeguards and system interlocks. Its proprietary locking mechanism eliminates the possibility of release during operations. A primary metal-metal seal is rated for 30,000 psi and a protective cap provides secondary barrier to wellbore fluid. The Non-Stop Driller™ sub retains access for ball drop tools and wireline services.
Benefits of Non-Stop Driller™
Nabors’ NSD system is designed to address operator concerns, including drilling efficiency, operational safety, hole condition and equipment integration. It enables:
Wellbore Improvements
Enhanced cleaning and continuous solids transport
Maintains a consistent annular pressure profile across the entire wellbore, eliminating stability problems
Minimizes bottom-hole pressure fluctuations in narrow pore pressure/fracture gradient applications
Minimizes connection gas and reduces risk of influx on connections
Underbalanced Drilling (UBD) and Managed Pressure Drilling (MPD) Utilization
Provides seamless integration to UBD/MPD operations, offering unprecedented bottom-hole pressure control on connections
Improves operational safety by eliminating surface pressure increases during connections
Eliminates post-connection stabilization time during multiphase drilling on air, foam, and two-phase wells
Reduced Non-Productive Time
Non-Stop Driller™ helps reduce NPT by mitigating:
Stuck pipe incidents
Extended wellbore conditioning and nuisance gas circulation
Casing running problems related to hole condition
Excessive bottomhole temperatures and bottom-hole assembly heat soak damage
Time required to re-establish two-phase circulation