Using horizontal technology to get hard-to-reach water.
By Lana Straub
The oilfield may come to mind when you think of angled wells.
Horizontal drilling and hydraulic fracturing have been the mainstay of the most recent oil boom. With this technology, oil drilling rigs drill down vertically and then horizontally until they reach their prospective oil “pay zone.”
Using this drilling method is often more expensive than traditional vertical drilling, but the expense is often justified by a tremendous yield of oil and gas from these previously unreachable zones.
So can this technology work for water?
Most traditional water wells are drilled vertically from top to bottom. However, this method means water zones must intersect horizontally with the vertical wellbore. Just like in oil and gas, if you miss the pay zone with your vertical bore, the gallons per minute produced by the well may not meet your customer’s needs.
There is also the chance there will be no water at all.
There are some groundwater professionals, both contractors and scientists, who think angled well technology can be beneficial for water systems. And so we feature here a roundtable discussion with some of these professionals.
Water Well Journal: Can you give us some insight why this angled method can be beneficial?
Gary Soden: Horizontal wells are beneficial when the property owner has no water available vertically.
David Traut: One of the most beneficial places to use this technology is river basins. Sometimes there are areas where if you move outside the river basin, you cannot get a satisfactory vertical well because of when the water carved its way through there and sedimentary sands redeposited in the river channel. Areas with poor surface water, particularly with high TDS, are also areas where this method is beneficial. We’ll drill under the river basin and let Mother Nature’s sands be the natural filter medium.
Michael Lubrecht: Horizontal wells are particularly attractive for relatively shallow, say under 150 feet, with a thin waterbearing layer, or for production of water from surface water bodies.
Some aquifers are fairly broad, but not thick. In those cases, a conventional vertical well can quickly exhaust the water supply in a small zone around the well— the cone of depression—and run out of water. Depending on the permeability of the soil, recharge, and other factors, a vertical well might be limited in how hard you can pump it without stressing the aquifer. If you put in several wells, you need to connect them all and sometimes access becomes a big issue.
In these circumstances, you can put a horizontal well near the bottom of the aquifer and extend it for hundreds of feet. This greatly increases the capacity of the well, and it still only has one well head to connect, one pump, etc.
John McCray: Horizontal and angled wells should be much more effective than vertical wells if you deduct where the water-bearing formations are, but they are much more expensive to drill. Of course, a single horizontal or angular well might be as effective as four or five vertical wells, so it might actually end up being cheaper.
WWJ: Is lithology an issue when deciding whether to use it?
John: The basic idea behind a horizontal well is it can better access fluids for most geologic settings. Oil, gas, and groundwater all exist in porous geologic formations that are primarily sedimentary. In the case of oil it is the organic matter that turns into oil, and in the case of water the sediment fills up as water rains into it or as lakes form over it.
David: If you are in a type of geology where a river cuts through the state and both sides of the river basin have difficulty getting water, we can drill parallel to the river basin or go under the river basin because many river basins are filled with gravel that was laid down with the water initially. We keep the horizontal incline, trying to avoid certain layers with lower quality water to find water that has lower total dissolved solids than the river water itself.
Michael: Rock or soil type is also a factor. The easiest drilling for directional rigs is a compact silty sand, but aquifers are found in a range of material types from boulders and cobbles to fractured bedrock. These can also be drilled, but sometimes with difficulty which can significantly increase the price.
Gary: Lithology determines the type of drilling technique. So if it is in hard rock, one has to use air hammer. We do water rotary in softer formations.
WWJ:What factors determine whether this method can be used?
Gary: This is done in hilly and mountainous areas where one can drive the drill rig up to the hillside and drill horizontally. They can be drilled from 50 feet to 1000 feet and more. This is not directional drilling where rigs start out at an angle, go a certain depth, and then go horizontal. The well is drilled horizontal from the start.
David:We drill slant wells, 12-foot diameter and larger, mainly for water supply wells in river basins. Since most of our wells are drilled next to the river, there are many factors to consider. There are setback issues—you have to deal with regulatory agencies drilling in a floodplain. There’s places on the Mississippi River where there’s granite on both sides—we know there’s gravel in the river bed but how do you get to it? Obviously vertical won’t work, so you go horizontal. We sometimes do 6-inch test pilot wells to determine whether it will work.
Michael: Depth of the well is an issue since it takes some horizontal distance to get to the desired depth. If your well is going to be 30 feet deep, it will take about 150 feet to achieve that depth, which is generally not an issue. However, if you wanted to put a well 500 feet deep, you would need to angle down for a horizontal distance of about 2500 feet to achieve your depth. Most sites don’t have that much space available.
The production requirements of the well can also be a factor. If a large volume of water must be produced, it will drive the diameter of the well casing and screen, as well as the pump that must be used. There are limitations on screen diameter and well length that relate to the capacity of the drill rig being used for the installation.
WWJ:What are some uses for angled wells?
Michael:We primarily do environmental remediation work and have numerous examples of vertical well installations that did not effectively clean up the site, which was then successfully remedied shortly after the installation of horizontal systems.
We installed a small horizontal system for a community on the Western Slope of the Rocky Mountains in Colorado where their primary water source was a spring on the side of a mountain. A horizontal well was installed that extended the spring piping and increased their flow. A vertical well would not even have been suitable in this situation since the system had no power available for pumps, and the horizontal well drained by gravity.
Gary: Most jobs we get to drill horizontal wells, we have tried to drill vertically and found no water. It is more of a “last resort” approach.
David: Our customers utilize this technology for water supply wells, generally either for municipal water supply or fracking water supply.
WWJ: Do you see horizontal and angled wells as a future niche market for drilling contractors?
David: I got into it by accident. Someone asked me if we could do it. It was a customer looking to solve a problem and we came up with a method to do it and then had more requests, so we kept finding better ways to do it. I can’t see it being a big market because it’s limited in scope where you can use it. If you can get conventional vertical water wells and you don’t have water quality issues, that would probably be more economical. We do about a half a dozen to 10 wells a year, working in about five different states year-round.
Michael:We are seeing a small increase in the number of queries we receive about the technology although it’s unlikely the market will support too many contractors. It’s difficult to develop expertise in both horizontal drilling and well installation. Most companies either install vertical wells or use horizontal drilling to install pipelines or utilities. It takes a commitment and a lot of crossover knowledge to do both. The investment in equipment and experienced personnel is a barrier to startups.
WWJ: Are there certain suppliers that cater to horizontal water well drilling? Are they from the oil and gas sector?
Michael:We use suppliers from several sectors for our materials. Some of the major suppliers, like Halliburton, Baroid, and Johnson Screen, supply to both the water well industry and oil and gas.
David:We buy regular steel casing from casing manufacturers. The customized downhole tools we use during the drilling process we make in-house.
You can see even though angled wells have been in use for several decades, all indicators show it’s a niche market. However, as water scarcity and drought continues to be an issue, innovations are being made to find water where it is. Angled wells will be a part of this future.
As the oil and gas drilling market begins to slow, perhaps their technologies will become more affordable and can be applied to water exploration. When searching for water for customers, every contractor will tell you:
“We’ve got to look at the problem from every possible angle.”
Lana Straub, with a background in the legal and financial aspects of small business, is the office manager of Straub Corp., Stanton, Texas, an environmental and water well drilling firm owned and operated by her family for more than 50 years. She can be reached at Lana@Straub Corporation.com.