Early Operations Of An Oil Field Intervention Submersible
Authors: Whitney John 
Published: October 2008

The submersible TAURUS A, launched in Feb. 1977, was designed to meet the needs of the modern offshore oil field. This involved providing capabilities equivalent to present submersibles for such things as pipeline and rig surveys. It also required new designs to coincide with the latest advances in oilfield technology. A much improved diver lockout system was provided to give more internal space and more gas and higher battery capacity than any earlier submersibles. Perhaps the most significant area in the TAURUS design is its ability to perform one atmosphere personnel transfer operations into subsea chambers. In order to perform true working personnel transfers, much larger capacity in payload, storage volume, ballast pumping rates, and hatch sizes were required as compared with earlier submersibles.

This paper discusses the basic philosophies behind the TAURUS design and how initial sea trials were performed to prove the new submersible's capabilities. These trials concentrated on the new dry transfer system that was eventually certified to a depth of 1,030 ft (314 m). This is being followed by work in conjunction with Vickers Oceanics Ltd. to demonstrate their Intertek subsea chamber system (these trials scheduled for completion prior to offshore Technology Conference). Other early operations also will be discussed, such as dives performed for the U. of Southern California.

The initial trials now successfully completed and full-scale subsea chamber work scheduled for completion by May 1978, TAURUS will provide a proved capability to the offshore oil industry for the one atmosphere transfer of personnel into subsea chambers, in addition to normal diver lockout work.

INTRODUCTION

As our demands for natural gas and oil continue to increase in our modern society, so must our production of such fuels. In the past few decades, the offshore oil industry has advanced its technology very rapidly in order to meet these present-day demands. As we continue to explore and increase production from beneath the ocean floor, man is finding it necessary to spend more and more time beneath the ocean surface.

It was not all that long ago that self contained underwater breathing apparatus (SCUBA) was invented, enabling man to descend to limited depths for short periods of time. Today's technology has advanced to the point where divers, using special gas mixtures, tables, decompression chambers, bells and highly qualified personnel, have completed tasks at depths exceeding 1,500 ft-an amazing accomplishment.

Unmanned submersibles of today also are finding their place in the offshore industry. These units are capable of surveying using both video and still cameras in conjunction with the submersible's navigation system. Manipulators also can be used for various light tasks. Unmanned submersibles have the advantage of having unlimited power because they generally are supplied power through an umbilical cable to a surface ship. This same umbilical, however, does lend itself to certain limitations such as maneuverability and depth capabilities. Entanglement of the umbilical and relative positioning of the surface vessel with respect to the submersible must be considered also.