Abstract: Geologic material in a borehole is weakened by accelerating a projectile into contact with the material. A drill bit is then used to bore through the weakened material. To accelerate the projectile, an endcap is placed in a conduit using a source of gas. The endcap isolates the conduit from the external environment. A projectile is then positioned in the conduit above the endcap. Movable members within the conduit are operated in sequence to enable single endcaps and projectiles to be moved into the conduit. Gas from the conduit is evacuated into an annulus between the conduit and a surrounding conduit, and a propellant material is provided into the conduit. The propellant material applies a force to the projectile to accelerate the projectile into contact with the geologic material. A fluid is circulated down a second annulus outside of the surrounding conduit to contact the drill bit and remove debris.

Abstract: Geologic material in a borehole is weakened by accelerating a projectile into contact with the material. A drill bit is then used to bore through the weakened material. To accelerate the projectile, an endcap is placed in a conduit using a source of gas. The endcap isolates the conduit from the external environment. A projectile is then positioned in the conduit above the endcap. Movable members within the conduit are operated in sequence to enable single endcaps and projectiles to be moved into the conduit. Gas from the conduit is evacuated into an annulus between the conduit and a surrounding conduit, and a propellant material is provided into the conduit. The propellant material applies a force to the projectile to accelerate the projectile into contact with the geologic material. A fluid is circulated down a second annulus outside of the surrounding conduit to contact the drill bit and remove debris.

Abstract: An SPM valve for use in a subsea environment includes a spool selectively movable between first and second positions to thereby arrange the valve in respective armed and disarmed configurations. The particular arrangement of a supply port and discharge port with respect to the spool permits a pressurized working fluid supplied to the supply port to bias the spool to both the first and second positions once an external force is applied to the spool to initially set the spool in either the first or second position.

Abstract: An SPM valve for use in a subsea environment includes a spool selectively movable between first and second positions to thereby arrange the valve in respective armed and disarmed configurations. The particular arrangement of a supply port and discharge port with respect to the spool permits a pressurized working fluid supplied to the supply port to bias the spool to both the first and second positions once an external force is applied to the spool to initially set the spool in either the first or second position.