Treatment of Contaminated Synthetic Based Muds (SBM) Drilling Waste in Block 47 Oman

Abstract

Abstract The development and use of Non Aqueous Fluids (NAF) like Oil Based Muds (OBM) and Synthetic Based Muds (SBM) for drilling operations during exploration and production of Oil & Gas has made the process more efficient and has helped develop new techniques in high depth drilling, offshore drilling and directional and horizontal drilling. The use of OBM's and SBM's carries an additional environmental liability for the operator, as the generated drilling waste ("cuttings") is contaminated with traces of the hydrocarbon base material used to prepare the drilling muds as well as crude oil, that posse an environmental hazard for on-site disposal. Typically 0.25 bbl of SBM are retained on cuttings per meter of hole drilled, the use of separation equipment and dryers can reduce the final percentage to < 5 % retention on the cuttings. However, this concentration is still high for a safe environmental disposal of the cuttings in most countries thus requiring treatment for further disposal of these solids. There are 3 main processes currently being used in the industry to deal with these wastes: The first option is Thermal Desorption (TD) where the cuttings are heated up to 800 C and the cuttings reduced to minerals and ash. The vapors are processed through a condenser and scrubbing system to avoid air emissions. This is an expensive process and requires regular PMS (preventive maintenance) Second option encapsulation where the cuttings are mixed with lime or silica and cement in varying ratios a concrete block is formed that can be buried in a land fill. Depending on the size of the block and percentage of cement, lime or silica the blocks can end up leaching and releasing the base fluid. The third and industry accepted application is bioremediation where active enzymes are mixed with water and the oils are digested into cell material, CO2 and H2O, the process is usually applied using land farming techniques. In this paper, we discuss the use of a technique that uses chemical, physical and biological processes to treat the solids under a land farming protocol that is more effective than straight bio-remediation.