FIELD MEASUREMENTS OF UNDERWATER NOISE 



FROM OFFSHORE OIL OPERATIONS 



1 JANUARY TO 20 JUNE 1980 



Waterborne noise measurements were taken in the vicinity of five 

 continental shelf oil and gas rigs. Two were production platforms, one was a 

 production platform also engaged in drilling, one was a man-made production 

 island, and one was a semi-submersible drilling rig. Airborne noise 

 measurements were taken in all major machinery spaces, and vibration 

 measurements were taken at various points on the support structure. The 

 waterborne, airborne, and vibration measures have not been compared as yet. 



Initial project measurements were made around Atlantic Richfield Company's 

 (ARCO) Platform Holly and man-made Island Rincon located off the southern 

 California coast. Platform Holly is Ih miles offshore of Goleta, California, 

 in 211 feet of water. Platform Holly is supported by eight legs in the form 

 of two parallel sets of four legs. The legs are anchored into the ocean floor 

 by pilings and filled with concrete. A view of Platform Holly is shown in 

 figure 1. Island Rincon is about 3,000 feet from shore approximately 10 miles 

 from Ventura, California, in 45 feet of water. It is connected to the 

 mainland by a trestleway, which carries the oil piping and electrical supply 

 lines. 



The instrumentation used for measurements at these two sites was borrowed 

 from Hubbs/Sea World Research. It consisted of a Bruel and Kjaer Type 3103 

 hydrophone, EG&G Model 113 preamplifier, and a NAGRA Model IV SJ magnetic tape 

 recorder. This instrumentation was limited by Tow hydrophone sensitivity and 



D-2 



