116 



3.2.2 Discussion: A Strawman of Potential Impacts 



To stimulate the discussion a straw-man was presented in the form of a list of "impacts" to the marine 

 environment which could "potentially" result from the development of an OCS oil and gas field (Kendall, section 

 2.1.4, Table 3). By no means was this list meant to be complete, rather, it was intended to stimulate and focus 

 the discussions. The participants prioritized those items to be addressed. These concerns included: historical 

 data; areas for study; activities potentially causing effects; parameters to measure, methods, quality assurance and 

 quality control (QA/QC); areal designs; and time frames. 



Historical Data 



Historical data includes both general and specific well information. General historical data would include dates 

 (in/out), depth drilled, volumes discharged, and drilling mud types used. The locations of the platforms and 

 individual wells would also be critical and would most likely be the most accurate, probably within a few feet. 

 It was felt that while MMS has this data (computerized), it may be difficult to retrieve in a form that would be 

 immediately usable. 



Specific historical well data would include the actual compositions and volumes of the additives used in the 

 formulation of the drilling muds. While some of this information will be available from daily mud logs, in some 

 instances stockpiled materials may have been used and accurate records not kept (e.g., diesel fuel for a stuck 

 pipe). 



Other historical data sets (and sources) which may be helpful include: discharge rates and depths; National 

 Pollution Elimination System/EPA discharge records; records of other activities (e.g., fishing/trawling); 

 meteorological records; records on produced waters, including volumes of discharges, composition, additives 

 (some of which could be used as tracers); produced sand; treatment processes; air quality data; base-line data; 

 records of pipelines; the use of antifouling materials; and the types and numbers of sacrificial anodes. Of 

 particular concern was that the baseline data, particularly biological, collected by the industry itself should not 

 be overlooked. 



Locations of Study Sites 



Referring to the study profile, the following restrictions were reiterated: "Appropriate sites in the Western and 

 Central Gulf of Mexico; probably far enough west to be outside the constant dominance of the Mississippi River 

 plume." 



Depth 



The depositional characteristics of a site are intimately associated with the energy of the environment and 

 consequently its depth. Shallow areas are typically high energy environments exhibiting cycles of deposition and 

 erosion. Long-term impacts resulting from the deposition of materials would most likely be minimal. Deep areas 

 are likely to remain undisturbed, however, the dilution of materials discharged at the surface may be sufficient 

 so that little if any deposition occurs. It is at the moderate depths where there is the potential for accumulation 

 leading to detectable impacts. 



Central vs. Western Gulf of Mexico 



The central vs. the western regions of the Gulf of Mexico (GOM) will be a criteria in study site(s) selection. 

 The central Gulf of Mexico (offshore Louisiana) is more frequently associated with oil production while western 

 areas (offshore Texas) with natural gas. This would, for example, influence any study examining the impacts 

 of produced waters: produced waters are more commonly associated with oil rather than gas production. 



Differences in geographical locations will also result in variations of the physical and biological characteristics. 

 For example, differences in the texture of the benthic sediments (e.g. hard bottoms verses soft bottoms-see 

 Rezneat M. Darnell, section 3.3, Figure 15). 



