Wellheads for Pressure Control on Wells

Wellhead

• A wellhead is a structure built over your drinking well to protect the different components. It consists of the upper end of the well casing that extends above ground, the well cap, the pressure gauge fitting, the vent and various connections that are found either above or below the ground.

Well Casing

• To control the flow of water from your well, you need to keep the water from leaking out of the casing by ensuring that the interface between the borehole wall and the casing is tightly sealed. If the pressure from the artesian well is expected to be more than 5 pounds per square inch, an outer casing should be installed before installing the permanent casing. In addition to stabilizing the soil around the wellhead, the outer casing will help contain the flow of water within the casing if the weight of the drilling fluid fails to overcome the pressure of the water flow.

Higher Pressure

• Stop water discharge in wells with a submersible pump by using a spool-type pitless unit designed to handle higher pressures. A hold-down spider inside the casing provides resistance against the pressure. Wells with high pressure and large flow rates can be even more problematic, while deep flowing wells and those sunk into bedrock experience fewer flow problems.

Other

• Attaching a pressure gauge to the casing pipe will let you measure the shut-in pressure of the well. The pressure gauge fitting should include a control valve in case it’s necessary to remove the pressure gauge. Flowing artesian wells should have a two-way vent installed on the well cap. A two-way vent allows for an exchange of air when the water level changes during the pumping cycle, and it will seal the well whenever the pump isn’t being used.