Effect of Drilling Cutting Discharge on Marine Environment and Benthic Foraminifera

Offshore oil and gas drilling operation activity can release many chemical components to environment. Water based muds (WBMs), oil based muds(OBMs) and synthetic based muds(SBMs) are the kinds of drilling muds. SBMs have the good characteristic of OBMs in operation time and so WBMs environmental advantage. Direct discharge to sea, transport to onshore to treatment and repump to well are the disposal methods for this muds. Barium and hydrocarbons are the basic components of drilling muds. Studies show that several year after the end of drilling cutting discharge, the level of sediment pollution by Barium and hydrocarbons around 250m of discharge point is high and after that hydrocarbons decrease quickly but Barium decreasing is slowly. Environmental evaluations show the bad effect of this waste on benthic foraminifera specifically around 250m of discharge point and increase the opportunistic species. The results show that the some of benthic foraminifera species can be successfully employed as bio-indicators of environmental change. The suggestions for environmental effect of these waste discharge includes: waste management for reach the zero- discharge, use of low environmental effect mud, environmental assessment and analyses before and after of drilling operation.