Function Testing Shear Rams

Pressure and Function Testing of Blind and Blind/Shear Rams

Blind ram BOPs and blind shear ram BOPs should not be tested with pipe in the stack. Instead, their suitability for use with the planned string must be verified with the manufacturer. Any non-shearable tools should be identified and clearly posted. For an accumulator test, simulate the operation of the blind or blind shear rams by closing and opening an alternate pipe ram.

API Spec 16A 7.5.8.7.4 Shear-Blind Ram Test Procedure

Each preventer equipped with shear-blind rams must undergo a shear test before going into service. As a minimum, the test shall involve shearing drill pipe according to the following specifications: 3-1/2”, 13.3 lb/ft, Grade E pipe for 7-1/16” BOPs, 5”, 19.5 lb/ft, Grade E pipe for 11-inch BOPs, and 5”, 19.5 lb/ft, Grade G pipe for 13-5/8” and larger BOPs. The test must be conducted without applying tension to the pipe and with no wellbore pressure present. Shearing and sealing must be accomplished in a single operation. The piston closing pressure should not exceed the manufacturer’s rated working pressure for the operating system. Verification confirms the performance and reliability of the equipment through a testing process that is both repeatable and reproducible. Many jurisdictions have additional requirements for shear rams used deep water, HTHP, and chemical (hydrocarbons, drilling fluid, acids, H2S, etc) environments.

NORSOK D-001 Standard: Section 5.10.3.1

Blow Out Preventer (BOP). The shear ram shall be capable of shearing the pipe “body of the highest grade drill pipe in use, as well as closing off the wellbore.”

Procedure for Shearing Pipe in the Stack

1. Space Out the Drill String: Ensure that no non-shearable components are positioned across from the shear rams. Identify these components ahead of time and post their locations in the dog house. Non-shearable components include tool joints, tool joint upsets, and BHA tools.
2. Centralize the Pipe: Close the hang-off ram below the shear rams to centralize the pipe.
3. Hang Off and Reduce Tension: For subsea operations, reduce tension on the compensators.
4. Bleed Off Trapped Wellbore Pressure: Release any trapped pressure around the shear rams.
5. Open Accumulator Bypass Valve: Open the accumulator bypass valve to direct full accumulator working pressure to the manifold.
6. Operate the Shear Rams: Engage the shear rams to attempt shearing the pipe.
7. Verify Shearing Success: Confirm that the string has been successfully sheared.
8. Monitor Well Integrity: Continue to monitor the well to ensure it remains securely closed.

Note: Always check the rating of the ram blocks used for hang-off. Variable bore ram blocks generally have lower hang-off capacity than fixed ram blocks. For more information on this or other well control subjects, visit my Well Control Manual at: https://learn-well-control.com/product/well-control-manual-by-edwin-ritchie/