Abstract: A system for operating a blowout preventer (BOP) includes a front piston positioned at least partially in a front chamber. The front chamber includes a front volume on a front side of the front piston, and a back volume on a back side of the front piston. The system also includes a back piston connected to the front piston. The back piston is positioned at least partially in a back chamber. The back chamber includes a front volume on a front side of the back piston, and a back volume on a back side of the back piston. The system also includes a first valve configured to permit fluid flow into the front chamber during a free closing stroke of the BOP. The system also includes a second valve configured to permit fluid flow between the front and back volumes of the back chamber during the free closing stroke.

Abstract: A system for operating a blowout preventer (BOP) includes a front piston positioned at least partially in a front chamber. The front chamber includes a front volume on a front side of the front piston, and a back volume on a back side of the front piston. The system also includes a back piston connected to the front piston. The back piston is positioned at least partially in a back chamber. The back chamber includes a front volume on a front side of the back piston, and a back volume on a back side of the back piston. The system also includes a first valve configured to permit fluid flow into the front chamber during a free closing stroke of the BOP. The system also includes a second valve configured to permit fluid flow between the front and back volumes of the back chamber during the free closing stroke.

Abstract: Various assemblies that can be used in a mud pump with a plunger-style piston to reduce seal failures, to offer control in variability of the circumference of the piston to thereby control fluid pressure, and to provide visibility into seal condition during operation. In one embodiment, a sleeve that can vary the overall effective circumference of the piston enables fluid pressure control. In some embodiments, seal failure within a pump can be monitored via a drain port that would receive drilling fluid leaking past a seal during operation of the pump. A discharge valve can be provided between an inlet and an outlet of the mud pump to reduce the load on pump components during start-up. Additional systems, devices, and methods are also disclosed.

Abstract: A load-balanced, high-capacity mud pump is provided. In some embodiments, load balancing is achieved by spacing hubs along the crankshaft of the mud pump with the bull gears disposed opposite one another, on outer ends of the crankshaft adjacent to the housing. In such an embodiment, the hubs are disposed along the crankshaft between the bull gears. A pinion shaft (or separate pair of shafts) can be provided, mechanically supported in the mud pump by roller bearings or lubricated pads. Additional systems, devices, and methods are also disclosed.

Abstract: A self-aligning mud pump apparatus is provided. In one embodiment, the mud pump includes a rotatable crankshaft, a crosshead, a crosshead guide, and a hub disposed in a housing. The hub is disposed on the crankshaft and is operable to convert rotating motion of the crankshaft to reciprocating motion of the crosshead within the crosshead guide. The hub is coupled to the crosshead via a connecting rod, which is connected the crosshead such that the connecting rod has five degrees of freedom with respect to the crosshead guide. The mud pump may also or instead include a piston coupled to the crosshead with five degrees of freedom between the piston and the crosshead. Additional systems, devices, and methods are also disclosed.

Abstract: Various assemblies that can be used in a mud pump with a plunger-style piston to reduce seal failures, to offer control in variability of the circumference of the piston to thereby control fluid pressure, and to provide visibility into seal condition during operation. In one embodiment, a sleeve that can vary the overall effective circumference of the piston enables fluid pressure control. In some embodiments, seal failure within a pump can be monitored via a drain port that would receive drilling fluid leaking past a seal during operation of the pump. A discharge valve can be provided between an inlet and an outlet of the mud pump to reduce the load on pump components during start-up. Additional systems, devices, and methods are also disclosed.

Abstract: A self-aligning mud pump apparatus is provided. In one embodiment, the mud pump includes a rotatable crankshaft, a crosshead, a crosshead guide, and a hub disposed in a housing. The hub is disposed on the crankshaft and is operable to convert rotating motion of the crankshaft to reciprocating motion of the crosshead within the crosshead guide. The hub is coupled to the crosshead via a connecting rod, which is connected the crosshead such that the connecting rod has five degrees of freedom with respect to the crosshead guide. The mud pump may also or instead include a piston coupled to the crosshead with five degrees of freedom between the piston and the crosshead. Additional systems, devices, and methods are also disclosed.

Abstract: A load-balanced, high-capacity mud pump is provided. In some embodiments, load balancing is achieved by spacing hubs along the crankshaft of the mud pump with the bull gears disposed opposite one another, on outer ends of the crankshaft adjacent to the housing. In such an embodiment, the hubs are disposed along the crankshaft between the bull gears. A pinion shaft (or separate pair of shafts) can be provided, mechanically supported in the mud pump by roller bearings or lubricated pads. Additional systems, devices, and methods are also disclosed.

Abstract: A blowout preventer may be used for shearing a tubular positioned in a bore extending through the blowout preventer. The blowout preventer includes a first shear ram movable towards the tubular, the first shear ram including a first blade, and the first blade including an outer cutting profile and an inner cutting profile. The blowout preventer further includes a second shear ram positioned opposite the first shear ram with respect to the tubular and movable towards the tubular, the second shear ram including a second blade, and the second blade including the outer cutting profile and the inner cutting profile. The outer cutting profile includes blade portions on opposite sides of the inner cutting profile, and positioned between an angle of about 120 degrees and an angle of about 140 degrees from each other.