Unloading a Well
Definition - What does Unloading a Well mean?
Unloading a Well is a technique in which borehole pressure is reduced from a borehole in order to cause the suction of hydrocarbon fluids into the wellbore from perforations made in the casing. This is made possible by the creation of a partial vacuum by the removal of air so as to force the hydrocarbons into the vacant space, thereby initiating a flow of liquids from a well. In simple words unloading a well means to remove fluids from tubing with the means of a swab.
Petropedia explains Unloading a Well
Once a well is complete and ready for production, the flow initiation has to be conducted through the unloading process. During the process, the hydrocarbon flow is initiated from a reservoir by removing the columns, tools, etc., thereby making the fluid approach the perforations made in the well casing through which the liquid seeps into the wellbore. There are various methods of unloading a well out of which swabbing is the common one. The other methods are circulation of lower density fluid and nitrogen lifting.In order to unload a well, a swabbing tool string is used which reduces pressure inside the wellbore by moving the tubing pipe, wireline tools and rubber cupped seals up the wellbore. Swabbing is a very specialized procedure and if not done in an effective manner, can lead to well instability in the form of well kicks and sudden shocks.