The Hydrofracturing Process
The procedure involves installing an inflatable packer in the well bore at least 20 feet below the well casing to ensure the process does not "break" the seal or allow surface water contaminants to enter the well. The packer is inflated or locked into position, and water is pumped through the packer under pressure. Most applications require between 500 to 2,000 pounds per square inch (PSI) pressure, and in some cases 3,000 PSI pressure may be needed in tight rock formations.
If successful, pressure will steadily rise to a maximum level as the rock formation resists flow, and then suddenly drop off and stabilize at a lower pressure. The drop in pressure indicates that the formation is accepting water and the resistance to flow is diminished. Water is pumped into the formation for 5 to 30 minutes. Injection pump delivery rates are 50 to 160 gallons per minute and generally 1,800 gallons of water per zone. Once the well starts to accept water and the pressure starts to decrease, it is all about how much water and how fast you can inject water into the fractures. The higher volumes increase velocity, which helps the cleaning process. The higher the amount of water used helps extend the fracture zone.
One or 2 packers may be used for hydrofracturing. When utilizing 1 packer, it is set near the top of the well but at a minimum safe distance below the drive shoe. After the initial pressurization or "hydrofrac" sequence, the packer is deflated and may be lowered further into the hole and the process is repeated. Two hydrofrac sequences are usually performed.
Zone isolation hydrofracturing utilizes a 2-packer system where the packers are placed in series and water is pumped into the isolated zones between the packers. This system can be more effective, because it concentrates pressures within a small area, typically 40 to 60 foot intervals, and individual fractures can be isolated and hydraulically fractured. With this method, approximately 8 zones are isolated within the well starting within a specified section. Each successive hydrofrac sequence stresses 1 interval higher than the last. In this way, all potential water bearing fractures or fracture zones are worked independently within the section of the well bore being hydrofracked. This differs from the single packer and 1- or 2-frac sequence method, which probably only affects the weakest, least resistant point(s) in the well.
When successful, hydrofracturing can produce modest yield increases. However, depending on the original yield of the well, a modestly increased yield may represent a significant increase if the original yield was very low. A typical well yield rate after hydrofracturing is ½ to 5 gallons per minute, though occasionally large increases in well recovery rates are realized. Due to geologic conditions, in some instances hydrofracturing will not increase well yield.
Because of the large volumes of water used in the process, we recommend waiting a minimum of 12 to 24 hours to conduct a yield test. This allows the bedrock aquifer to reach equilibrium and ensures a truer test.
It is extremely important that only clean(not water pulled from lakes, ponds or streams), disinfected water is used for injection because of the extreme pressures involved and the potential for forcing contaminant deep into the bedrock aquifer. Our well drilling company uses only clean potable water from our own water well. We use 3,600 gallons on a single fracture job and up to 10,000 gallons on a zone fracture job.
Although there is no way to predict exactly what the outcome will be, Precision Well & Pump Systems provides a 98% success rate using the hydrofracturing process. We strongly recommend it to well owners suffering from inadequate water yield.
Contact us today at 401-539-0029 to schedule hydrofracturing and increase the yield power of your well.
3600 gallons of water
Competitors use only 500-2000
The only dual pump frack equipment in Rhode Island
Precision Well & Pump Systems, inc. Hydrofracturing Hydrofrack