Frequently Asked Questions
1. How do you avoid existing services?
Services are located using dial before you dig information and careful vacuum or hand excavation of all services crossing the bore path. The depth of these services are recorded and incorporated into the bore design.
2. What is a frac out and how are they controlled?
A frac out occurs if the driller has not addressed the fracture gradient of the subsoil formation and taken the necessary steps to avoid unnecessary pressure down hole. In many cases this cannot be helped and can happen with sudden changes in the geotechnical make up of the ground. In such cases vacuum trucks are made available to cleanup and remove material. In many cases changes to the mud mix can reduce the fracture.
3. Why does the surface you are drilling under lift sometimes?
This occurs if the cuttings are allowed to build up in the hole, usually as a result of improper flow rates, inadequate support equipment or the wrong drilling fluid mix. More importantly hole collapse due to changes in geotechnical conditions can create this issue. To prevent this suitable mud plans are developed and adhered to, UEA staff receive appropriate training and the flow of cuttings are monitored at all times.
4. Why does the pipe get stuck or come out flat?
This can happen for a number of reasons, such as hole collapse, an unclean hole and incorrect mud plans. Also the choice to install a cheaper product with a thinner wall can lead to the pipe being installed flat. The pipe design needs to take into account the drill pressure created down the hole at all times so UEA recommends the use of PN 16 material where possible as a minimum.
5. What happens if the drill rods break off?
Whilst this is a very rare and unfortunate situation it is not the end of the bore. UEA has a number of options of retrieving any tooling lost down the hole. In certain cases a separate directional drilling rig can be mobilised and set up at the exit side. The rods are then sent down the hole to assist with the removal of the tooling. Tooling can break and to reduce this risk UEA operates a concise maintenance system.
6. How do you weld the polyethylene pipe?
Polyethylene is welded by Butt Fusion Welding process. This involves heating the two prepared ends to a pre determined temperature and then bringing these two ends together at a set pressure until the fuse creates a continuous pipe of equal strength.