Oil Well Double Ram Blowout Preventer BOP API 16A Well Control Equipment

Double Ram Blowout Preventer – API 16A Dual-Cavity Well Control Equipment

Product Overview

The double ram blowout preventer (BOP) is a critical well control device installed at the wellhead to seal, control, and monitor oil and gas wells during drilling, workover, well servicing, and oil testing operations-. As the name suggests, a double ram BOP contains two sets of ram blocks (two pairs of opposing rams) housed within a single, unitized body. Each set of rams is independently operated, allowing the BOP to perform multiple sealing functions without requiring additional equipment.

The primary purpose of any ram BOP is to prevent the uncontrolled release of oil, gas, or formation fluids from the well—a catastrophic event known as a blowout. By providing two independent sealing cavities in one compact assembly, the double ram BOP offers enhanced well control capability, space savings, and operational efficiency compared to using two separate single ram BOPs.

All our double ram BOPs are designed, manufactured, and tested in accordance with API Spec 16A—the international standard for drill-through equipment—and can be supplied with NACE MR0175 compliance for sour service (H₂S) environments.

Double Ram vs. Single Ram BOP – Key Advantages

While both single and double ram BOPs serve the same fundamental purpose, the double ram configuration offers several distinct advantages:

The double ram BOP is particularly valuable in deep wells and offshore operations where rig space is at a premium and multiple sealing functions are required-. By combining two ram compartments into one unitized body, the double ram BOP reduces the overall height of the BOP stack, simplifies installation, and minimizes potential leak paths.

Ram Types – Four Configurations for Every Well Control Scenario

The ram blocks installed in each cavity determine the BOP's sealing capability-. We offer four types of rams, which can be mixed and matched in a double ram BOP:

Common double ram configurations include:

Pipe Ram + Pipe Ram – Allows sealing on two different pipe sizes (e.g., 4½″ and 5″) without changing rams

Pipe Ram + Blind Ram – Provides both annular sealing (when pipe is present) and full wellbore closure (when pipe is absent)

Pipe Ram + Shear Ram – Offers both routine sealing and emergency shearing capability in one unit

Variable Diameter Ram + Pipe Ram – Provides flexibility for varying pipe sizes in the same well

Pipe rams are the most commonly used type. They feature rubber packing elements that conform to the outside diameter of the pipe, creating a pressure-tight seal while still allowing fluid circulation within the drill pipe.

Blind rams have no openings for tubulars. When closed, they completely seal the wellbore—ideal for situations where the drill string has been pulled out of the hole.

Shear rams are equipped with hardened steel blades that can cut through drill pipe, tubing, or even wireline cables in an emergency. After shearing, the ram seals the wellbore, providing a final barrier.

Variable diameter rams offer flexibility by sealing around different pipe sizes within a specified range, eliminating the need to change ram blocks when the drill string diameter changes.

Key Features – Engineered for Safety and Reliability

1. API 16A & NACE MR0175 Compliance

All our double ram BOPs are manufactured in accordance with API Spec 16A, the industry standard governing blowout preventers and associated well control equipment. For sour service applications, they meet NACE MR0175/ISO 15156 requirements for H₂S resistance.

2. Forged Alloy Steel Construction

Major pressure-bearing parts are forged from high-strength alloy steel, providing superior strength, impact toughness, and the ability to avoid casting defects. This ensures exceptional durability under extreme downhole pressures.

3. Two Independent Ram Cavities

The double ram BOP contains two separate ram cavities within a single body, each with its own set of rams, operating pistons, and locking mechanisms. Each cavity can be operated independently, providing operational flexibility and redundancy.

4. Hydraulic Opening/Closing with Manual Locking

The rams are opened and closed hydraulically for fast, reliable operation. A manual locking device is provided as standard configuration, ensuring the rams remain securely closed even in the event of hydraulic pressure loss. Locking options include manual, hydraulic, and tandem booster configurations.

5. Floating Seal Structure Between Side Door and Body

A floating seal structure is applied between the side door (bonnet) and the body. This design strengthens sealing performance using wellbore pressure while reducing the pre-tightening force required on side door bolts.

6. Oval Ram and Cavity Design

The oval ram and cavity design reduces stress concentration in the BOP body and provides maximum contact area with the drill pipe, casing, or tubing. This ensures a lower rubber pressure and increased seal life.

7. Self-Energising Seals

Sealing is energised by well pressure acting on the ram and is maintained even with the loss of BOP operating pressure. Seals are pressureenergised, meaning the higher the well pressure, the tighter the seal.

8. Quick Ram ChangeOut

Hydraulic opening bonnets separate the bonnets from the body and expose the ram assemblies for fast and convenient ram changeout. This significantly reduces downtime during routine maintenance or when changing ram types.

9. Wide Pressure and Size Range

Our double ram BOPs are available in bore sizes from 71/16″ to 30″ and working pressures from 2,000 psi to 20,000 psi (14 MPa to 140 MPa)-.

10. Multiple Connection Types

The BOP is offered with studded, flanged, and hubbed top and bottom connections-. Flange sizes, bolts, clamps, and ring grooves conform to API 16A and GOST standards.

11. Multiple Product Specification Levels

Available in PSL 1 through PSL 4, with PR1 and PR2 performance requirements. Higher PSL levels impose additional requirements for material chemistry, hardness control, and nondestructive examination.

12. Temperature Range

Rated for operation from 29°C to +121°C (Class P-U), with extended temperature options available for specialized applications.

Technical Specifications – Available Combinations

Our double ram BOPs are available in the following bore size and pressure combinations:

Operational Applications – How the Double Ram BOP Works

When Pipe is in the Well

When drill pipe, tubing, or casing is present, the pipe ram or variable diameter ram in one or both cavities can be closed to seal the annular space between the pipe exterior and the casing or wellbore. The ram packing elements conform to the pipe OD, creating a pressure-tight seal.

When No Pipe is in the Well

When the wellbore is empty, the blind ram can be closed to completely seal the wellhead. This is typically done when the drill string has been pulled out for tripping or when the well is shut in for extended periods.

Emergency Shearing

In critical situations where the drill pipe cannot be retrieved, the shear ram can be activated to cut through the pipe and seal the wellbore. This is a last-resort measure to prevent a blowout. Our shear rams can cut S-135 grade drill pipe.

Dual Function Capability

One of the key advantages of a double ram BOP is the ability to perform two different functions simultaneously. For example:

Pipe ram in the lower cavity seals around the drill pipe

Blind ram in the upper cavity is ready to seal the well if the pipe is pulled out

Suspending and Stabilizing the String

Certain ram types (pipe rams and variable diameter rams) can suspend and stabilize the drill string in addition to sealing the annulus.

Well Control Operations

Once the well has been sealed, the BOP's side outlets allow operators to perform essential well control operations through the connected choke and kill manifold:

Circulating drilling fluid to condition the mud

Choking to control wellbore pressure

Killing the well by pumping heavy fluid

Releasing pressure safely

Long-Term Well Closure

When the wellhead must remain closed for an extended period, each ram can be mechanically locked using the integrated locking device. This ensures the seal remains intact even if hydraulic pressure is lost.

Contact us to order the right double ram blowout preventer for your drilling or workover operation. We provide the correct bore size, pressure rating, ram configuration, and connection type for your specific well conditions—with full API 16A compliance, NACE MR0175 sour service capability where required, and on-time delivery.