The swabbing process is essential to controlling and maintaining oilfield wells. It’s so important, in fact, that we wrote a previous blog post about it last year. While that article discussed the swabbing process, we wanted to add to it by explaining the machinery and operations involved in the process.
What Does a Swab Look Like?
A typical swab rig is comprised of a winch with a cable, a pulley or foldable mast with a sheave and a drive system. The mast is raised above the well that needs to be serviced. Once centered over the well, a skilled swab operator will then lower the cable and appropriate tools into the well. Once the cable reaches the fluid level, swab cups collect the excess fluid that inhibits oil or gas and raises it back out of the well. It’s just like fetching a pail of water from a regular well.
The winches used to power swabbing operations are traditionally powered by engines with a typical chain and sprocket transmission, however, Tiger General has improved on the process. Instead of this traditional transmission, we provide hydraulic drives that are more efficient than their outdated predecessors. In fact, these hydraulic drives deliver 95% mechanical torque efficiency. Compare this to mechanical chain drive systems that can lose up to 30% torque through their outmoded inefficiencies.
Swab Rig Operators
While the process seems rather straightforward, it does require a good deal of skill and know-how from an experienced operator. The operator must have an intimate knowledge of not only his or her rig, but the wells themselves.
A good swabbing service depends on a sharp eye and good instincts from the operator. Centering the cable and swab cups over the well can feel like threading a needle to the unseasoned operator, but a seasoned veteran can do it with ease. Furthermore, lowering the cups to the precise level is another skill. Operators shoot for an industry standard of removing six barrels of “dead fluid” from wells. This is usually enough to relieve the hydrostatic pressure of the well and get oil and gas pushing up once again.