Drilling sludge

Compositions of a N,N-dialkylamide of a fatty acid in a hydrocarbon solvent and a mutual oil-water solvent are useful for the prevention of sludge formation or emulsion formation during the drilling or workover of producing oil wells [1526,1528,1529]. 

J.Romocki. Application ofN,N-dialkylamides to control the formation of emulsions or sludge during drilling or workover of producing oil weUs. Patent WO 9522585,1995. 

Biological treatment may be used to degrade the oil and grease fractions in drilling fluids prior to solids separation. Marks et al. [33] conducted batch treatment tests for drilling fluids and production sludges and demonstrated that biological treatment is feasible. However, more biokinetic tests are required for further evaluation. 

Several emerging processes may be applicable for treatment of oily drilling muds prior to disposal. One process being tested in Europe involves the use of an electric distillation kiln to break down solids-laden oil-based drilling muds [13]. Another process uses critical fluid to extract oil and organics from oily sludges so that they can be landhlled [34]. Copa and Dietrich [14] treated a sample of spent drilling mud with wet air oxidation. The COD content was reduced by 45 to 64% and the dewaterability of the mud was improved. 

Copa, W.M. Dietrich, M.J. Wet oxidation of oils, oil refinery sludges, and spent drilling muds. Proceedings of Oil Waste Management Alternatives Symposium, California Dept, of Health Services Oakland, California, April, 1988. 

High-rate anodic dissolution of metals has been studied intensively (Reviews [9, 12, 14, 21]). Several types of anodic metal dissolution are recognized. Sometimes, the dissolution of metals in the active state is used in ECM. Deep, small-diameter holes drilled in acidic solutions are an example. An acid is used in order to avoid sludge formation, which hampers the drilling. However, highly aggressive... 

DSS Feed System. The DSS feed system consisted of an agitated, 55-gallon polyethylene supply tank for the sewage sludge and standard piping and pumps. The feed system supplied two air-sparged tubes located 25 cm and 46 cm above the distributor plate in the EHE. Each tube contained six, 2.36 mm diameter holes drilled horizontally (3 on each side) through which DSS and air were fed. Because the clay and lime additives used in the study had a tendency to settle out in the supply tank, a recirculation line was also installed. 

Drilling. Common drill rigs available for monitor-well installation include cable tool, air rotary, mud rotary, reverse rotary, and hollow-stem auger. The cable tool rig repeatedly lifts and drops a drill bit, drill stem, drilling jars, and rope socket. The drill bit crushes hard rock or loosens unconsolidated material and mixes the loosened particles with water to form a slurry or sludge. The sludge is removed at intervals by a sand pump or a bailer. 

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