TOMS CANYON STUDY 



Dr. Robert C. Ayers, Jr. 

 Exxon Production Research Co. 

 Houston, TX 



Exploratory drilling activity on the Middle Atlantic OCS was at its peak 

 during the years 1978 to 1981. Environmental concern about potential adverse 

 impact prompted Government-mandated studies, including one at Toms Canyon. 

 The wellsite, in Block 815, is at the edge of the continental shelf about 

 150 km from the New Jersey Coast and about 3.7 km northeast (up current) from 

 Toms Canyon. The Government required the lessee, Exxon USA, to perform a 

 monitoring study to determine if discharges from the well were entering the . 

 canyon in harmful quantities. The study was carried out by EG&G under the 

 direction of Exxon Production Research Company. 



The field study, from September 1980 to April 1981, included a pre- 

 drilling survey, four cruises during the drilling period, and continuous 

 monitoring of currents and sedimentation at several locations from the 

 drilling rig to midcanyon. The pre-drilling survey included bathymetry; 

 sediment sampling for background measurements of barium, chromium and 

 vanadium; and grain size analysis and sampling of biota. The bilogical 

 samples were to be analyzed only if Exxon drilled another well in Block 815 or 

 in any other block adjacent to Toms Canyon. Since no other wells were 

 drilled, the biological samples were never analyzed. 



The sampling design included three transects, one running southwest and 

 downcurrent from the rig site across the canyon, one along the canyon axis, 

 and one north-south across the shelf break through the rig site. Bottom 

 samples were taken and water properties were measured throughout the water 

 column. Sediment traps and current meters were located near the bottom, and 

 in the upper water column near the rig, at the canyon rim and at mid-canyon. 



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