Hydrofracting – What is That?

HYDROFRACTING or Hydrofracturing is a technology originally developed for oil wells, which increases the well bore permeability. This technology has been successfully used on domestic and commercial water wells over the past decade or so.

In water wells, the hydrofracting process goes something like this:

The pump, piping and wire are removed from the well using a hoist truck set up over the well. The hoist is then used to lower a packer into the well below the casing. A packer is a steel, plug-like device, fitted with a hard, tight fitting rubber sleeve. Once the packer has been lowered to the selected depth in the well, the rubber sleeve is inflated setting the packer firmly in place.

Water from a tank truck is then pumped through the center of the packer, filling the well below. High volume pumps capable of pressures of up to 3000 psi are used for this purpose, though pressures this high are seldom reached in water well remediation.  Water is pumped into the well bore quickly building pressure until a sudden drop in pressure occurs indicating a break through. If the pressure was high enough, the rock pressure is overcome, the rock is cracked and a fluid filled fracture is opened up. The overburden can actually be lifted up and pumping in more fluid can extend the crack. [The overburden is the rock layers above the fractured rock.] It is not necessary to have very large cracks to increase the permeability dramatically (tenths of an inch or less).

Hydrofracting often results in increased well yield and has been used to get old wells that have “dried up” to produce once again. There have been cases where dramatic well yield increases have been realized but these are in the minority. Most hydrofractings results in an increase of a gallon or two per minute in marginal wells but often the increased yield is considerably less than that and sometimes there is no increase at all.

Pump tests to determine the effect of hydrofracting should be done after the well has been used for at least 48 hours. Pump tests run immediately after hydrofracting prove little since they will simply be pumping back out the thousand or more gallons that was just pumped in to hydrofract the well!

Not All Wells Are Good Candidates for Hydrofraturing

There are cases on record in which hydrofracting of one well has caused a nearby well to go dry. There was even one case of note in Texas where the hydrofracting of an oil well affected a water well two miles away.  Adverse publicity like this has caused some municipalities to out law hydrofracturing altogether.

That being said, Hydrofracturing is performed on thousands of wells every day in the US but is not appropriate for all wells. Wells in sand or other loose materials, or those that don’t perform because they are constructed in dense soils that are not dense enough to be fractured or those that are large diameter like 24” and 36” bored or dug wells are not candidates for this procedure.  Even shallow rock wells are often poor candidates because the packer needs to be installed below the well casing and once that is done there just isn’t much wall left to be fractured.

Hard Rock Aquifers

Drilling in hard rock aquifers can be a hit or miss proposition. It is possible to drill a hole in some formations and never encounter a fracture. Even if there are water bearing fractures a few feet away, if you don’t connect with one, you have a dry well.

In the picture, well #1 is a dry hole even though there is a water bearing fracture nearby. Hydrofracting this well could produce a connection to this fracture. Trouble is, in real life, there is nothing to show that there is such a nearby fracture so it is always a gamble when you decide to spend the money in an attempt to turn a well that never did produce water into one that does.

Hydrofracting as a Means of Improving Plumbing or irrigation Performance

In a vast majority of cases hydrofracting brings fractional increases in well yield. If you have a 1 gallon per minute well you may be able to turn it into a 1.5 gpm well; If you have a 2 gpm well you may be able to increase it to 3 gpm and so forth. If you want to be able to take two showers at the same time or use all of your bathrooms at once or get an irrigation system that is not currently working properly because of insufficient well yield to function correctly, this is simply not going to make enough difference alone to provide the kind of performance you are looking for.

Hydrofracting That Doesn’t Last

Hydrofracting generally doesn’t turn a low yield well into a great well, though it can on occasion.  A hydrofracted well will probably have a better yield than it did before but, in most cases, will still be a low yield well.

If you talk to the right people you will hear stories of wells that were hydrofracted a couple of years ago and are beginning to show signs of needing it again. Why is this?

The reason is that low yield wells are over pumped constantly and this can cause their feeding fractures to be choked off.

Under normal conditions water flows very slowly through the fractures in an aquifer from areas with high pressure toward those where the pressure is lower. The rate of flow depends on the size of the fracture and the difference in the pressure.

A ten gallon per minute well pumped at a rate of 10 gpm results in little change in static level inside a well and water flows toward the well bore relatively slowly because the feeding fractures are under water – there is backpressure on them. In the case of a one gallon per minute well that is being pumped at 10 gpm the water level in the well bore recedes quickly when the pump is  running because you are borrowing from storage to make up the difference between the yield and what is being withdrawn. 

Borrowing from storage inevitably results in the well being pumped below the feeding fractures. When this happens all back pressure is removed from the fractures and water entering the well is free to flow as fast as it can through those fractures in the area immediately surrounding the well. This increase in velocity causes debris, grit and silt that had settled out in the fractures to be picked up and carried toward the well. Clogging can occur in situations where the fractures narrow in the direction of the well. Exposing bleeding fractures to the air can also result in mineral buildup at the point of entry into the well bore and encourage biological growth. All of these can cause clogging of the fractures that connect the well bore to the aquifer, reducing or completely shutting off the water supply over time.

Low yield wells resurrected by hydrofracting and put back in service using the same collection methods that caused the problem to begin with are very likely to need their fractures cleaned out again in a few years.

Hydrofracturing and Well Manager®

A Well Manager®, on the other hand, can provide the kind of performance people are looking for using wells normally considered inadequate. By simply installing a Well Manager to keep the well producing you can provide enough water and performance to run all of the plumbing in a building at the same time. Often there is enough water for irrigation when used with a properly designed system.

Hydrofracting when used in conjunction with the installation of a Well Manager® on a well of declining yield or even one that has “gone dry” can often result in restoration of the water supply and greatly improved plumbing performance.

When dealing with a well that did produce water but has “dried up” you are working with one that was connected to water bearing fractures. Whether or not hydrofracting will bring it back to life depends on the reason it ceased producing.

Well #2 in the picture shows a connection to the aquifer very near the water table. If the level in this aquifer recedes even a few feet this well will cease to produce. To get it producing again you would need to install a packer in the bore below the dry fracture and try to open up a new fracture low enough to connect the well bore to a wet fracture farther down the well. Sometimes this works and sometimes it doesn’t.

If you have a well suffering from diminishing yield that has finally ceased to produce even though nearby wells have a fairly high static level then chances are the fractures are clogged as a result of over pumping but are still wet past the obstruction.

It is often possible to hydrofract such a well, cleaning and widening the fractures so that it begins to produce once again. When you use a Well Manager with a well like this you don’t need much production to turn it back into a usable water supply AND since a Well Manager can be adjusted to operate without over pumping (pumping the well down and exposing the feeding fractures) the results obtained from your hydrofracting investment will last much longer.

We have used this technique a number of times with great success. Among those on our testimonial page are three customers for whom hydrofracting was a part of the process; Bob Snell, Julius Nemeth, and Wayne Smith.

A Well Manager® can improve performance – more pressure and more volume – by itself using the poorest wells, hydrofracting most often does not. When the well is so poor that a Well Manager cannot provide enough water then hydrofracting can often improve the yield enough that a Well Manager can give you the water you need and the performance you want!