A Look at the Factors That Affect the Chances of Swabbing

During the lifetime of oil and gas wells, much fluid is produced. At the first drilling, the well is fracked to open up production zones. Swabbing is used to recover fluids to kick the wells off. 
Of the fluids, about 40% return at kick-off. The fluid flows back with the natural gas and oil. As the well ages, the pressure in the bottom hole diminishes. Due to insufficient pressure, all the fluids are not pushed out of the well. Production suffers if fluid is formed at the top of oil or gas. That is when swabbing is necessary to maintain production.

This article gives a brief idea about oilfield swabbing and variables that affect its chances. 

What Is Swabbing?

Swabbing happens due to a reduction in bottom hole pressure below the formation pressure due to the effects of drill string-pulling. This allows an inflow of formation fluids into the wellbore. 

The swabbing process allows access to the production areas of the oil wells. It facilitates taking out fracking liquids gathered in the areas. Drilling companies use swabbing to release the well’s bottom hole pressure, which facilitates ‘kick’ it off. 

Drilling companies use pressurized liquids to break the site while creating a new well. Swabbing comes next, and it helps create channels and production zones for the oil and gas to move.

Factors That Affect Swabbing

1 - Mud properties – The poor properties of mud, such as high viscosity, high gel strength, high rheology, etc., can induce swab kick at the time of pulling out. Monitoring the drilling fluid properties is crucial, and the technicians need to devise action plans to maintain the mud in good condition. 

2 - Pulling speed – The tripping speed affects the inflow. The faster the speed, the higher chances there to swab influx. The personnel must monitor the well during pulling out, and the pulling speed should not induce the well control situation. 

3 - Formation pressure vs. hydrostatic pressure – Swabbing the well can be easy if the hydrostatic pressure is the same as or a little above formation pressure. To alleviate this problem, the overbalance margin or trip margin should be more than the reduction in pressure achieved by swabbing. 

4 - Swelling/Heaving Formations – A small clearance is created between an open hole and a BHA due to a reduction in wellbore diameter caused by swelling and heaving formation. There is a higher chance to swab in the well, when pulling out with a small clearance. 

Final Words

The swabbing and fluid removal process is important for an oil well, as it builds the conditions for better gas and oil yield. If you are interested in swabbing in Grande Prairie, please connect with Swab Pro Ltd.