Selecting the correct ram blowout preventer for a given well requires more than just matching a catalog number. This guide walks you through the complete selection process used by CAMTOP Shanghai Machinery Equipment Co., Ltd. engineers when sizing WU-series ram BOPs for customer projects worldwide.

Step 1 — Determine the Required Bore Size

The bore size of a ram BOP must be equal to or greater than the largest OD that will be run through it — typically the drill bit or casing shoe.

Typical Casing / Wellhead Size Recommended Minimum BOP Bore CAMTOP WU Model
7″ casing / 7-1/16″ wellhead 7-1/16″ (179 mm) FZ18-14/21/35/70/105
9-5/8″ casing / 11″ wellhead 11″ (279 mm) 2FZ28-35/70
13-3/8″ casing / 13-5/8″ wellhead 13-5/8″ (346 mm) 2FZ34-14/35/70/105
16″ or 18-5/8″ casing 20-3/4″ (527 mm) 2FZ52-14/21/35
20″ or 21-1/4″ conductor 21-1/4″ or 26-3/4″ FZ54-14 / FZ68-14

Step 2 — Select the Pressure Class

The BOP working pressure rating must equal or exceed the Maximum Anticipated Surface Pressure (MASP) for the well.

Pressure Class Working Pressure (PSI) Typical Application
2,000 PSI 2,000 (13.8 MPa) Shallow gas, workover, surface completion
3,000 PSI 3,000 (20.7 MPa) Medium-depth onshore wells
5,000 PSI 5,000 (34.5 MPa) Standard onshore and offshore drilling
10,000 PSI 10,000 (69.0 MPa) High-pressure onshore / offshore exploration
15,000 PSI 15,000 (103.4 MPa) Deep high-pressure wells, HPHT applications

Step 3 — Consider Temperature Rating

API 16A defines three temperature classes: K (–20°C to +121°C), L (–46°C to +121°C), P (–60°C to +121°C). Standard CAMTOP WU-series BOPs are rated to Temperature Class K.

Step 4 — Specify Material / Trim Class for Fluid Environment

Service Environment Material Class
Sweet service (no H₂S) AA (standard)
Mild sour service BB or CC
Full sour service (≥0.05 psia H₂S) DD, EE, FF, or HH

CAMTOP WU-Series Ram BOP — Full Size Range

Bore (in) Pressure (PSI) Config Weight (approx)
7-1/16″ 2,000–15,000 Single & Double 180–420 kg
11″ 3,000–10,000 Single & Double 400–700 kg
13-5/8″ 3,000–10,000 Single & Double 800–1,600 kg
20-3/4″ 2,000–5,000 Single & Double 2,200–3,500 kg

Need a BOP sizing recommendation? Send us your well design parameters and CAMTOP’s engineering team will respond within 24 hours: sales@cposl.com | +86.21.58432768