Piezocone Torpedo

The need for deep penetration in deep waters combined with the need for reducing the cost of geotechnical investigations lead Petrobras to the development of a piezocone to be installed at the tip of a torpedo-pile).

Main dimensions of the torpedo-piezocone is the same as in the regular piezocone, (u₁, u₂, inclination).

Challenges:

i) Very high water pressure – 2000m water depth;

ii) The difficulties related to the excess pore-pressure measurement, (hundreds of kPas in the case of soft clays) with respect to very high ambient water pressure;

iii) The lack of a pore-pressure reference during free-fall.

Requirements (i) to (iii) resulted in the development of an internal compensation system, which has been designed by GROM Acústica & Automação and successfully tested in the hyperbaric chamber facilities at CENPES (PETROBRAS Research and Development Center).

PAPER: The Development of the Torpedo-Piezocone – Porto et al., OMAE2010-20820