TOMS CANYON STUDY 



R, C. AYERS, JH. AND J. E, O'REILLY 



EXXON PRODUCTION RESEARCH COMPANY 



DURING THE PERIOD 1978-81 EXPLORATORY DRILLING ACTIVITY ON THE 

 MID- ATLANTIC OCS WAS AT ITS PEAK. ALSO, DURlHQ THIS PERIOD, 

 ENVIRONMENTAL CONCERN OVER THE IMPACT OP DRILLING IN THIS 

 FRONTIER AREA WAS QUITE HIGH. TO ADDRESS THE ENVIRONMENTAL 

 ISSUES, GOVERNMENT MANDATED STUDIES ON DRILLING DISCHARGB IMPACTS 

 WERE CONDUCTED BY INDUSTRY. THE TOMS CANYON STUDY WAS ONE OF 

 THESE. THE WELI^ITE IN BLOCK 816, LOCATED APPROXIMATELY 150 km 

 FROM THE NEW JERSEY COAST, WAS ALSO LOCATED APPROXIMATELY 3.7 }3n 

 NORTH EAST AND UPCURRENT OP TOMS CANYON. THE MID-ATLANTIC 

 BIOLOGICAL TASK FORCE RECOMMENDED TO USGS THAT THE LESSEE, EXXON 

 USA, BE REQUIRED TO PERFORM A MONITORING STUDY TO DETERMINE IF 

 DISCHARGES FROM THE WELL WERE ENTERING THE CANYON IN HARMFUL 

 QUANTITIES. EXXON USA AGREED TO FUND THE STUDY WHICH WAS CARRIED 

 OUT BY EGiG ENVIRONMENTAL CONSULTANTS UNDER THE DIRECTION OF 

 EXXON PRODUCTION RESEARCH COMPANY. 



THE MONITORING STUDY, CONDUCTED IN 1980-81, CONSISTED OF A 

 PRE-DRILLINC, SEDIMENT SAMPLING SURVEY AND THREE DRILLING PHASE 

 SURVEYS. IT INCLUDED MEASUREMENTS OF CURRENTS, WATER PROPERTIES, 

 PHYSICAL AND CHEMICAL CHARACTERISTICS OF BOTTOM SEDIMENTS AND 

 MATERIAL COLLECTED IN SEDIMENT TRAPS, A BATHYMETRIC SURVEY, AND 

 THE COMPOSITION AND QUANTITY OF DISCHARGED MATERIAL. BARIUM (FROM 

 BARITE) WAS USED AS A CONSERVATIVE TRACER OF THE DRILLING 

 DISCHARGES. IT WAS FOUND THAT ELEVATED BARIUM LEVELS COULD BE 

 DETECTED IN MATERIAL DEPOSITED IN SEDIMENT TRAPS AT THE RIM OF 

 THE CANYON. HOWEVER, THE DEPOSITION RATES FROM THE DISCHARGES 

 WERE TOO LOW TO MEASURABLY INCREASE CONCENTRATIONS OF BARIUM 

 IN SEDIMENTS LOCATED FURTHER THAN 1-1.5 km FROM THE WELLS ITE. 



B-7 



