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You are here: NOV.com > Solutions > Drilling > Drilling Pressure Control > Blowout Preventers
NXT-RAM Blowout Preventer
NXT
RAM Blowout Preventer

After years of limited changes in the development of BOP design, the National Oilwell Varco (NOV) line of Shaffer® NXT® BOP Systems offers the drilling industry improved drilling economics in a new generation of well control systems. This new generation BOP has changed the performance expectations for pressure control equipment, offering significant advantages and features.

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BOLTLESS BOP DOORS: NOV's Shaffer NXT BOP Systems are unique in providing a means of significantly improving safety and efficiency in the critical path of activity. With the replacement of the door bolts in ram BOPs, NOV has eliminated the time consuming manual practice of using brute force to torque up numerous large door bolts. A number of benefits have been realized with this development:

Reduced Weight (lightest BOP systems in the industry)

Reduced Height (smallest BOP systems in the industry)

Elimination of Manual Labor Under Time Pressure

Elimination of Cross Threading Bolts

Ram Changes go from 4 hours to 40 minutes (15 Minutes with an ARC™ Automated Ram Changer)

HYDRAULIC SYSTEM: Hydraulic power to operate a Model NXT ram BOP can be furnished by any standard oil field accumulator system. Hydraulic passages drilled through the body eliminate the need for external manifold pipes between the hinges. Each set of rams requires only one opening and one closing line. There are two opening and two closing hydraulic ports, clearly marked, on the back side of the BOP. The extra hydraulic ports facilitate connecting the control system to the preventer. A standard hydraulic accumulator unit will close any Model NXT ram.

RAM CHANGING SYSTEMS: NOV's Shaffer ARC Automated Ram Changing System provides an additional edge in ram changing economics and safety by eliminating all hands-on activity involved in changing rams. The ARC can reduce the crew working on ram changing activities from 4-5 people to 1-2 people. A simple ram-changing arm retrieves and replaces rams in minutes quickly and accurately from a simple removable ram storage magazine.

18-¾" BOP SYSTEMS: The introduction of the NXT Ram BOP was initially in the 18-¾", 15,000 psi size. This system was designed to enable a stack height and weight package similar to a 13" BOP configuration and provide the capability of eliminating the dual stack drilling system with a through bore wellhead connector. Actuation of the boltless door mechanism is available in two configurations:

  • Remote or door mounted hydraulic operation.
  • Simple manual mechanical door actuation at the ram door.

WELDLESS CAVITY: The introduction of no weld cavities in previous Shaffer BOP designs is carried on in the NXT models. This feature introduces replaceable parts to the cavity to eliminate extensive in-shop repairs and post weld heat treatments. The seal seat, skid plate and side pads can be replaced upgrading the BOP cavity tolerances to as new condition.

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CASING SHEAR: Shaffer engineers have extended the capabilities of shear rams with a casing shear ram which meets the specific cutting needs to physically shear casing tubulars up to 13"; in an 18-¾"; bore BOP.

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TYPE CVX SHEAR RAM: The type CVX Shear Ram enhances the features of NOV's Shaffer Shear Ram family, assuring multiple shear and sealing sequences while hung off in a cavity below the shear ram cavity. No additional force is required to manipulate the fish. This multiple shear and seal capability enhances shear ram reliability and extends the length of BOP stack deployment. Type CVX Shear Rams are capable of shearing at 20% lower pressures than conventional shear rams.

CVX Shear Rams are designed for durability and convenience, and provide the reliable performance that today's BOP equipment demands. The CVX Shear Rams are offered for large bore, high pressure BOPs.

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MULTIRAM™: NOV addresses the need for changing out rams on a tapered drillstring by offering MULTIRAM blocks to cover a range of varying sizes of drill pipe from 3-½" to 5" and 5" to 7". The MULTIRAM introduces the potential for the elimination of additional ram BOPs to facilitate the changes in tubular OD on any given string.

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ULTRATEMP™: NOV's conservative Shaffer testing procedures call for maintaining pressure and temperature for the duration of the test. Even with these stringent demands, the UltraTemp rams hold in witnessed testing. NOV's Shaffer UltraTemp rams are designed to seal in temperatures as low as 20°F. This eliminates the need to heat the BOPs and/or the test medium when the surface ambient temperature is low.

NOV's Shaffer UltraTemp ram assemblies are designed to safely withstand wellbore pressures up to 15,000 psi and extreme temperatures up to 350°F (177°C) for prolonged periods. This translates into rigsite capability to safely evacuate personnel and equipment in the event of a major high temperature, high pressure kick.

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UltraTemp

ULTRALOCK™ II RAM LOCKING SYSTEM:

The UltraLock™ II locking system incorporates a mechanical locking mechanism within the piston assembly. This locking system is not dependent on closing pressure to maintain a positive lock. It uses flat tapered locking segments carried by the operating piston which engages another stationary tapered shaft located within the operating cylinder. Using SL-D™ rams, the UltraLock™ II has hang-off capabilities up to 600,000 pounds at full working pressure. The system needs no adjustments, no matter the size of the pipe rams. Different size or type ram assemblies can be freely interchanged.

Only one hydraulic function is required to operate the cylinder's open/close function and the locking system. The system automatically locks in the closed position each time the piston assembly is closed. Once the operating piston is closed on the pipe, the locks are engaged until opening pressure is applied. Only hydraulic pressure can unlock and reopen the preventer.