When a water well produces less than expected, the problem is often not the aquifer itself but the connection between the aquifer and the borehole. Hydraulic fracturing - also called hydrofracturing - is a proven method of re-establishing that connection. It is widely used in water wells, and it is completely different from the high-volume fracturing carried out in the oil and gas industry.
At the centre of the process is a relatively simple piece of equipment: the hydraulic fracturing packer.
What hydrofracturing does
In a water well, water is injected into a sealed section of the borehole at high pressure. The pressure opens existing fractures in the rock and washes out the clay and fine material that has blocked them. Because the water is injected into a sealed interval, practically all of the pressure acts on the formation instead of escaping up the borehole.
Typical water well hydrofracturing is carried out at pressures in the range of 500 to 2,000 psi (about 35 to 140 bar), with some applications going higher. The required pressure depends on the rock type, the depth and the condition of the well.
What the packer does
The packer isolates the interval that is to be treated. A single inflatable packer is set above (or below) the target zone; a double packer arrangement - two packers on one string - isolates a section between them, which gives much better control of where the water goes.
The packer is inflated with water or air through a small line. Once inflated, a check valve holds the pressure, and the high-pressure injection then takes place through the central tube of the packer or through the string below it.
How an inflatable packer is constructed
An inflatable packer has three main parts: a central tube, a reinforced rubber sleeve, and an inflation port. The sleeve is built from natural or synthetic rubber reinforced with two or more layers of steel wire. The wire layers control the expansion range and the pressure the sleeve can withstand.
The rubber compound determines the working temperature range and the resistance to oil, chemicals and repeated inflation cycles. Natural rubber offers excellent elasticity and recovery; nitrile (NBR) and EPDM compounds are used where oil or chemical resistance is required.
Single packer or double packer?
A single packer is the simplest and most economical option. It is used when the target zone is at the bottom of the hole or when the whole open section below the packer is to be treated.
A double (straddle) packer is used when a specific interval must be treated. Two packers are mounted on one string with a spacing tube between them. The treated interval is exactly the section between the two sleeves, which is important in long open-hole sections and in wells with several production zones.
What to specify when ordering a packer
Five parameters determine the correct packer for a job:
1. Borehole diameter. The packer must pass freely into the hole and expand against the wall. Check both the nominal diameter and the actual diameter of the hole, and allow for washouts and irregularities.
2. Inflation pressure and working pressure. The inflation pressure expands the sleeve; the working pressure is the pressure applied to the formation. Both must be within the rated range of the packer, and the equipment should be protected with a pressure relief valve.
3. Depth and temperature. Deeper wells mean higher hydrostatic pressure and often higher temperatures. Make sure the sleeve compound suits the well temperature.
4. Length of the sealing element. A longer sleeve provides a better seal in rough or oval boreholes; a shorter sleeve is easier to set and release.
5. Reusability. Reusable packers with replaceable rubber elements are the economical choice for contractors who treat many wells. Single-use packers are used where the packer remains in the hole.
The accessories matter as much as the packer
A packer alone cannot do the job. A typical hydrofracturing set includes:
- a high-pressure pump capable of reaching the required pressure,
- high-pressure hoses and steel pipe with rated working pressure well above the planned injection pressure,
- a four-way manifold with valves and a pressure gauge,
- adapters to connect the packer to the pipe string,
- spare rubber elements and check valves.
Choosing hoses and fittings with a lower pressure rating than the pump is one of the most common and most dangerous mistakes in hydrofracturing work.
Installation notes
Lower the packer to the required depth slowly, avoiding impacts against the casing or the borehole wall. Inflate gradually and watch the pressure gauge: a stable reading means the sleeve is seated. Do not over-inflate; expansion beyond the recommended diameter damages the sleeve and can make it impossible to retrieve. After the treatment, release the pressure completely before pulling the packer out.
Store packers deflated, away from direct sunlight, oil and ozone. Rubber that is stored inflated ages much faster and loses its ability to return to its original diameter.
About Bangtian
Hebei Bangtian Mine Safety Equipment Co., Ltd. manufactures hydraulic fracturing packers, inflatable grouting packers and the associated high-pressure accessories - hoses, pipe, manifolds and adapters - for water well, mining and geotechnical applications.
If you tell us your well diameter, depth and the pressure you plan to use, we will recommend a suitable packer and a complete set of accessories.
