December 15, 2025 | Susan Napier-Sewell

Lessons Learned: Gas Leak Leads to Activation of Cable Rams

A gas leak migrating through cable armor layer and E-line BOP rams leads to activation of cable shear rams.

While securing a well by setting a deep plug with mono conductor cable size 5/16”, after several failed attempts to set the plug, a gas leak was observed on the grease injection head and grease return hose. The cable rams were closed and grease was injected between the rams as per normal procedure.

While working to reestablish the grease injection head functionality it was attempted multiple times to bleed down the pressure above the BOP rams with negative results.

BOP shear rams were activated and well secured with the closure of the hydraulic master valve.

What happened?

Plan: Original scope: perform PLT with E-line.

Lower Master Valve (LMV) difficult to operate, decided to secure well with deep set and shallow set plugs in the well in order to repair the LMV using 5/16 mono cable.

Operation with course of events:

02:10: At setting depth with plug. Made several attempts to set the plug and release the running tool but without confirmation of success.
10:10: Observed gas leak on the GIH and grease return hose. Closed cable rams in BOP, and pumped grease between rams.
Was not able to reestablish grease supply to all inlets in the Grease Injection Head (GIH). –> 16:15: Attempted to bleed down pressure above BOP multiple times. NoGo.
17:00 Decided to activate BOP shear ram and cut the wireline cable. Closed swab and hydraulic master valve. Well secured.

What Went Wrong?

Loss of active element in primary barrier. Most likely formation of hydrates in grease inlets to GIH. Was able to pump grease through the grease injection ports when the lubricator had been laid down.
100 % MEG was used during the operation for leak testing of rig up etc.
Gas migrating passed the closed cable rams, most likely through the armour layers in the cable as the cable had been stationary for ca. 8 hours.

Corrective Actions and Recommendations:

Lessons learned:

Primary well control in wireline is a combination of wireline cable, GIH, BOP and grease, which are tested and supplied from different vendors. There is no standard for qualification/verification of the full well control system.
Mono cable had to be used for correlation of the deep plug due to the completion design.

Recommended actions:

Perform full scale test of rig up (GIH/ BOP/cable) in representative well conditions.
For high pressure gas wells: Install a MEG injection point below the GIH.
Establish governing documentation for intervention operations in high pressure wells (bleed-off system fit for purpose, cable selection, grease type, BOP ram configuration). Also establish governing documentation for testing/verification of well control system (combination of BOP, GIH, cable and grease).

Impact: Minor gas release through GIH, Lost time.