Intervention BOPs are not drilling BOPs — and the workshop discipline is not the same.

Intervention crews bring us their BOPs because the workshops they used to use kept treating a 5-1/8" 10K Coiled Tubing Quad like a small drilling stack. It isn't. A CT Quad has four cavities that have to coordinate a single closure event around a piece of live coil — blind, shear, slip, pipe — and if the seal kit you fitted last week was the wrong durometer, you find out at 7,000 psi with the well open.

Snubbing stacks have a different problem. The upper and lower stripper rams have to seal under tubing motion, not against a static joint. Wireline grease BOPs have a third problem again — the seal is not a ram at all but a column of injected grease and a stack of replaceable packing. Three asset classes, three workshop disciplines, one test bench that has to know the difference. Most general-rotating shops don't.

Our job on the way in is to find what the unit log doesn't. Our job on the way out is to hand back a stack and a file the operator HSE engineer can sign in five minutes. That paperwork is the difference between getting on the well-pad and waiting in the lay-down yard.

For a CT Quad BOP — typically 5-1/8" 10K, Cameron / NOV / Hydril — the standard scope is: full strip to component, MPI on every ferrous part, UT thickness on the body, dimensional CMM against the OEM datum, hardness Rockwell C with a ≤ 22 HRC ceiling per NACE MR0175 / ISO 15156, dye-penetrant on every sealing surface, replace every elastomer in HNBR sour-service grade, replace blind and shear blocks where the cutting edge is inside the OEM scrap dim, hydrostatic shell at 1.5× WP = 15,000 psi held 30 minutes, function test on each of the four cavities with closure-time records, and an API 16A 5-year recert stamp on release. Typical TAT is 4-6 weeks bench-to-truck.

For a snubbing BOP stack — typically 7-1/16" 10K with upper + lower stripper rams plus a safety ram and pipe ram — the scope is the same plus a stripper ram rebuild that is its own discipline. Stripper packers are renewed in HNBR, the stripper bore is honed and re-measured, and the function test includes a moving-tubing leak check. Typical TAT is 6-10 weeks. For slickline / wireline BOPs — bore typically 5-1/8" or smaller, grease-injection plus packing — the scope reduces to grease-circuit strip, packing-stack renewal, hydrotest, function. Typical TAT is 1-2 weeks; mostly grease and packing.

A drilling BOP closes on a static drill pipe and holds. A snubbing stripper has to seal a tubing string that is moving in or out. That is not the same elastomer problem and it is not the same test. If your shop runs both lines through the same mental model, you are going to lose a stripper at the wrong time.— Hassan Al Awadi · Stripper Rebuild Specialist · Jebel Ali

Every CT, snubbing or wireline BOP that comes through the bay runs through the same four phases. The phase content changes by asset class; the discipline does not.

Below is the abridged SOP that governs an intervention-BOP recert in our shop. The full document is asset-class specific and runs to three annexes. This is the subset that gets ticked off, dated and signed on every work order.

Below is the typical-findings table across a year of intervention-BOP intakes. The three highlighted rows are the ones we see most often that an operator HSE engineer will not let on a well-pad without intervention.

On release the unit goes back on the truck or container with a fresh API 16A 5-year recert sticker, a single FAT pack — NDT records, hardness logs, torque sheets, hydrotest curve, function records, recert cert — and a closure / seat time record per cavity. The crew can hand the file straight to the operator HSE engineer and clear the well-pad on first read. The same file format applies whether the asset is a CT Quad, a snubbing stack or a wireline grease BOP.