Close-In Procedures: Guidelines for Shutting the Well In
A close-in procedure is a set of actions taken to safely shut in a well and stop the flow if primary well control is lost. It involves quickly implementing secondary barriers to regain control. The procedure should meet the following criteria:
- Familiar to the Crew – The team should be well-acquainted with the procedure.
- Industry-Recognized – The method should be widely accepted in the industry.
- Appropriate for Current Conditions – The procedure must be suitable for the specific situation.
- Regularly Practiced – It should be part of routine BOP (Blowout Preventer) drills.
Options for Closing the Well In
There are two main methods for closing a well in:
- Soft Close-In
- Hard Close-In
The steps to shut in will vary depending on the rig’s current activity, such as drilling, tripping in/out, running casing, cementing, wireline operations, or running a completion string. However, the general principle is to shut in from top to bottom. Start by closing the top preventer, and if it fails, immediately close the next preventer in the stack.
Key Steps in the Close-In Procedure
- Shut in Early and Quickly: The goal is to minimize the influx volume as soon as possible. The sooner the well is shut in, the better the chances of preventing further complications.
- Crew Awareness: Every crew member must be vigilant for signs of a kick and immediately notify the driller if any warning signs appear.
- Flow Diversion: If the well is to remain shut in for an extended period, it is good practice to divert the flow line to the trip tank and set an alarm.
Consequences of a Larger Influx
If the influx is large, it reduces the hydrostatic pressure in the annulus, assuming the influx is lighter than the well fluid. As the hydrostatic pressure drops, the wellbore pressures above the influx increase. Higher pressures in the open wellbore raise the risk of breaking through the weakest formation, which could lead to:
- Lost circulation
- Underground blowouts
- Possible surface blowouts
Advantages of Early Kick Detection
The key to minimizing the risk of a kick escalating to an uncontrolled blowout is early detection and taking action as quickly as possible. Early kick detection offers the following advantages:
- Minimizes Kick Volume: The sooner you shut in, the less influx there will be.
- Minimizes Wellbore Pressures: Early shut-in reduces the pressure buildup in the wellbore.
- Reduces the Risk of Losses: Less influx means less chance of losing control.
- Prevents Damage to Preventer Rubbers: If a kick is not shut in quickly, the flowing well may damage the preventer rubbers, making it harder to secure the well.
Well Control Manual V2.6 by Edwin Ritchie
