--> --> The Potential Environmental Impacts of Disposing Drilling Wastes in Drilling Pits Constructed in Sabkha Deposits: A Case Study

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The Potential Environmental Impacts of Disposing Drilling Wastes in Drilling Pits Constructed in Sabkha Deposits: A Case Study

Abstract

Drilling activities generate large quantities of exhausted drilling fluids and solid cuttings usually referred to as drilling wastes. Proper management of these wastes is one of the challenges faced by the drilling companies especially if these wastes contain hazardous materials. Drilling wastes need to be disposed of properly to minimize the potential contamination to the surrounding environments. Before final disposal into secured landfills, drilling wastes are discharged into open pits adjacent to the drilling site to dry out the solid cuttings. Many of the drilling pits are sometimes constructed into salt marshes that extend over large areas where drilling activities take place. Salt marshes are highly saline deposits that are hydraulically connected to local groundwater aquifers and are, therefore, considered sensitive and delicate environments. Disposing the drilling wastes into these deposits may cause a number of environmental and safety impacts. The rise of groundwater level in salt marshes may cause settlement or sink holes and impose stress on the structures built in these areas. Leaching of the hazardous chemicals from these dumping sites to the underground water sources is another serious issue to be considered. In this study, the potential environmental impacts that will be resulted from drilling an onshore oil exploration well were assessed. The well is drilled into an area where the subsurface water has a very high salinity of more than 330,000 ppm. A complete characterization of the soil for the chemicals of concern (COC) such as TPH, BTEX, PAHs and metals was performed in this study to understand the current baseline conditions. It was estimated that more than 500 m3 of drilling wastes are expected to be generated in this project. Potential significant environmental impacts were identified and analyzed. Finally, the mitigation measures recommended to offset the impacts of drilling wastes are also discussed in this study.