2. Structure & Material Composition

Integrated composite structure

• Elastomer main body: Premium HNBR/NBR rubber alloy with large rubber storage capacity, excellent elasticity, oil & mud resistance, anti-H₂S sour gas performance optional for sulfur-containing wells.

• Embedded segmented metal support ribs: Evenly distributed radial steel skeletons integrated with rubber via vulcanization; guide radial contraction and prevent rubber extrusion & flip during sealing.

• Hemispherical outer profile matching the spherical inner surface of BOP top cover, forming uniform stress transmission when closed.

Working temperature range

3. Working Principle

1. Seal wellhead: Hydraulic oil pushes the BOP piston upward, squeezing the spherical rubber core against the spherical top cover; segmented support ribs draw closer, extruding rubber inward to tightly wrap drill pipe, drill collar, wireline or fully seal empty bore, utilizing well pressure auxiliary sealing for zero leakage under rated working pressure.

2. Open wellhead: Hydraulic reversing releases piston thrust; the rubber core rebounds automatically via its own elasticity to reset and open the central channel.

4. Core Performance Advantages

1. Wide sealing adaptability: Can seal pipe strings of any outer diameter within rated bore range, realize stripping operation of 18° tool joints to run/pull drill pipe under pressure.

2. Anti-flip rubber design: Spherical structural limit avoids rubber upturning damage under high well pressure, far longer service life than cone rubber core during frequent stripping operations.

3. Strong well pressure boosting sealing effect: Downhole pressure compresses the rubber core inward to reinforce sealing reliability under high pressure conditions.

4. Low friction loss: Large rubber reserve reduces abrasion during repeated opening/closing and stripping; segmented ribs lower sliding friction resistance.

5. Uniform stress distribution: Hemispherical contact eliminates local stress concentration, no cracking or tearing under long-term alternating hydraulic impact.

6. Easy maintenance: Single-piece integrated design, independent replacement without disassembling the whole BOP stack; complete repair sealing kits available as supporting parts.

5. Common Standard Specifications

• Nominal bore: 7-1/16" ~ 21-1/4"

• Working pressure grade: 35MPa / 70MPa (5000psi / 10000psi)

• Pressure resistance range: 2000–15000psi customizable

6. Main Application Scenarios

1. Land & offshore conventional oil/gas well drilling;

2. Sour gas, high-temperature deep well and geothermal well control;

3. Workover, snubbing operation and well testing construction;

4. Cooperate with ram BOP to form complete BOP stack, preventing blowout risks caused by formation kick.

7. Functional Value