Anese was called to carry out a variant of a steel pipeline under pressure, in the municipality of Matera, in order to restore the conduct that has been discovered, in some places, because of ground erosion.
The main weaknesses encountered were:
- A complex logistics: the construction site was located in an isolated area characterized by several drops and was deprived of a water supply. This led to optimize water consumption as needed with tankers refuel
- Soil: clayey silt Sandy gravel clasts with low rare alternate ending. Clay blue-grey from a medium consisting to a very large and extremely plastic.
- Small horizons fractured clay with high risk of tuffaceous intercalated frac-out
- The company has completed a horizontal directional drilling of 570 meters.
- The was made of steel and its diameter was 250 mm (10 “), thickness of 7.8 mm and was covered by a layered of polyethylene.
To get the job done, a drilling station of 100ton was used.
Given the plastic consistency of the clay, during the preparation of the drilling fluid additives were mixed to limit the swelling caused by excessive moisture, which could cause excessive friction of the tube during launching operations.
During pilot hole, a pressure control system of sludge in the bottom hole was used In order to keep the pressure within the established range by the executive plan, and limiting the possible phenomena of frack-out
- replacing the pipeline deep enough to be safeguarded against future erosion
- environmental protection thanks to constant monitoring of pressure of the drilling mud in order to maintain proper stability of the walls of the hole and confining inside all mud flows/material required