Technology of drilling through gate valve plate of oil and gas wellhead under pressure and replacing gate valve under pressure
Technology Introduction
With the continuation of the gas field production time, due to various reasons, the valve of the gas production wellhead has been seriously corroded, the valve stem is broken and the switch is out of control, which affects production and poses certain safety risks. This technology uses a hydraulic system to work to avoid sparks caused by electrical equipment. After the valve plate of the out-of-control valve is drilled through, the valve can be replaced under pressure. The entire drilling process is carried out in a sealed environment, equipped with high-pressure water circulating cooling to ensure safe and reliable drilling operations.
Technical advantages
1) There is no need to stop the normal production of oil and gas wells during the operation, no need to kill wells, and no need for large-scale equipment
2) A variety of blocking methods, positive and negative pressure, multi-stage sealing and double sealing, according to different valves on site, different blocking methods can be selected
3) No harm to oil and gas formations, no pollution, and no impact on oil and gas well productivity
4) No pollution to the ecological environment
5) Hydraulic dynamic control during the whole operation process, safe and reliable
6) The work efficiency is high, and the work time does not exceed 6 hours
Technical parameters of constructable wellhead
Applicable pressure: ≤35MPa (5000Psi)
Nominal diameter of well head: φ52mm (21/16˝), φ65 mm (29/16 ˝), φ79 mm (31/8 ˝)
Comparison of three valve replacement technologies
project | Valve replacement for traditional well killing operations | Blocker seat sealing valve | Valve replacement under pressure (drilling) |
Device Configuration | Use large and complex well killing equipment, such as workover rigs, solids control systems, mud circulation systems, etc. | Need crane, logging truck and special tools | Only small special tools required |
Environmental protection | Mud and mud pool need to be treated in compliance with environmental protection standards | Generally no pollution, if the plug is out of control, it will seriously pollute the environment | No pollution |
Job safety | Relying on liquid column to balance formation pressure at any time | There is no external pressure control for setting, and there is a risk of setting failure, leading to leakage, blowout, and out of control | Full hydraulic control, safe and reliable |
Work cycle | 7~15 days | 3~5 days | 4~6 hours |
| Operating cost | high | in | low |
