Can a Reverse Unit Help an Oil or Gas Well?
A reverse unit is designed not to extract oil or gas, but to send unwanted materials to another well. This other well is usually a disposal well, and is used to get rid of drilling fluids, debris, and toxic waste. Most of these fluids are too toxic to leave on the Earth's surface, but will be safer once sent deep underground. Since the process of oil drilling creates plenty of these materials, extraction companies typically have disposal wells near all of the production wells they dig.
The term "reverse unit" refers to the simple fact that these pumps are meant to send material down into the ground. A normal well pump, on the other hand, is designed to suck material up to the surface.
Making a pump work in reverse isn't as simple as flicking a switch to the opposite position. Pushing fluid down into the ground typically requires overcoming resistive pressure, and a regular pump isn't able to do that for long. Therefore, it is important to use a purpose-built reverse pump for that purpose.
Sometimes, a reverse unit is used not just to get rid of material, but to push it towards a productive well. This use is one of the things you might see when you get oil and gas well servicing in West Texas. For this use, fluids are still pumped into the ground, but it is done in such a way that once the fluids spread out, they push desired materials toward the well that's being serviced. Fluids of different compositions and temperatures are used according to the geologic conditions of the site. The process can help rejuvenate wells that have become lackluster in their productivity. It is quite popular in Texas.