How to prevent collapse and blowout during well drilling

Collapse and blowout are two severe accidents that may occur during well drilling, posing significant threats to personnel safety and operational progress. To prevent these situations, the following measures can be taken:

1. Measures to prevent collapse:

1. Mud management:

Use mud with appropriate density and viscosity to support the wellbore wall and balance the formation pressure.

During the drilling process, the pressure of the mud column is maintained slightly higher than the formation pore pressure to prevent the invasion of formation material into the wellbore.

2. Stratigraphic evaluation:

Conduct a thorough formation evaluation before drilling to understand the formation characteristics and pressure, and predict potential collapse risks.

For complex formations, specially designed wellbore protection tools, such as wellbore liners or casings, may be required to enhance wellbore stability.

3. Well control technology:

Apply appropriate well control techniques and pressure management strategies to monitor changes in bottomhole pressure and formation pressure.

Equip with emergency standby mud to quickly replenish mud to stabilize the wellbore wall in case of a small-scale collapse.

4. Operational specifications:

Operate strictly in accordance with drilling procedures and operating regulations, avoiding carelessness and unauthorized operations.

During sensitive periods such as tripping or changing the drill bit, special attention should be paid to controlling the speed and mud circulation to prevent inducing collapse.

II. Measures to prevent blowout:

1. Blowout preventer stack:

Install a suitable blowout preventer (BOP) stack at the wellhead, including semi-seal, full-seal blowout preventers, shear rams, etc., to quickly cut off wellhead pressure in emergency situations.

2. Pressure detection:

Monitor the bottom hole pressure and formation pressure in real time to detect abnormal signals promptly.

Upon detecting abnormal pressure changes, drilling should be immediately stopped, the situation assessed, and appropriate measures taken.

3. Well control training:

Conduct regular well control training for the drilling team to ensure that each member is familiar with the operation of blowout preventers and blowout prevention measures.

Train to respond to various possible well control scenarios, including simulating response capabilities in emergency situations.

4. Mud pump and throttle valve:

Ensure that key equipment such as mud pumps and throttle valves are in good condition and capable of responding quickly to pressure changes.

In the event of a mud pump failure, the system can quickly switch to the standby pump to maintain the continuity of the mud circulation system.

By implementing the aforementioned measures, the risks of collapse and blowout during well drilling can be significantly reduced. It is crucial to have a strict supervision mechanism and emergency response plan in place, so that potential issues can be quickly identified and addressed.