Selecting the correct ram type for each cavity in your BOP stack is one of the most important decisions in a well control program. CAMTOP Shanghai engineers have helped drilling teams worldwide configure BOP stacks for everything from shallow onshore gas wells to high-pressure deepwater exploration programs.

Quick Reference: Four Ram Types at a Glance

Ram Type Primary Function Pipe in Hole? Key Limitation
Pipe Ram Seal on specific pipe OD Yes (specific size) Fixed to one pipe OD range
Variable Bore Ram (VBR) Seal on a range of pipe ODs Yes (multiple sizes) Cannot shear pipe
Blind Ram Seal open hole (no pipe) No — open hole only Cannot seal when pipe is in hole
Shear Blind Ram Cut pipe AND seal open hole Yes (cuts through it) High cost; pipe is severed after shearing

Pipe Rams — The Workhorse of the BOP Stack

Pipe rams have a U-shaped face profile precisely machined to match a specific pipe outer diameter (OD). CAMTOP pipe rams for the WU-series cover all standard API drill pipe and tubing sizes from 2-3/8″ through 13-3/8″ OD.

Limitation: Pipe rams are fixed to one OD — a 5″ pipe ram set will not seal on 3-1/2″ or 5-1/2″ pipe.

Variable Bore Rams (VBR) — Flexibility Without Compromise

A single CAMTOP VBR set for an 11″ bore BOP can typically seal on pipe ODs from 3-1/2″ to 7″. Choose VBRs when your well program uses more than one drill pipe size, or when you are running coiled tubing or snubbing.

Blind Rams — Sealing the Open Hole

Blind rams are designed to close the wellbore when no tubular is present in the hole.

⚠️ Critical Warning: Do NOT attempt to close blind rams with drill pipe or any tubular in the bore.

Shear Blind Rams — The Last Line of Defense

Shearing blind rams combine two functions: they first use hardened steel blades to shear through the drill pipe, then the front packing elements seal the cut wellbore. CAMTOP SBRs are engineered to shear standard API drill pipe at rated working pressure.

Recommended BOP Stack Configurations

Application Double Ram BOP Triple Ram BOP
Standard onshore drilling Pipe Ram + Shear Blind VBR + Pipe Ram + Shear Blind
Multiple pipe sizes, onshore VBR + Shear Blind VBR + Pipe Ram + Shear Blind
High-pressure offshore Pipe Ram + Shear Blind Pipe Ram + VBR + Shear Blind

Not sure which ram configuration is right for your well program? Contact CAMTOP: sales@cposl.com | +86.21.58432768 | www.camtop-oilfieldtools.com/