A procedure is described by which oil flushing during coring of steamed and unsteamed heavy oil formations can be estimated. Chemical tracers in the drilling mud are used to indicate if filtrate invasion is occurring. Core saturation analyses are coupled with data from high velocity corefloods and temperature-dependent residual oil saturation measurements to estimate oil flushing during coring.

Keywords:
saturation, tracer concentration, residual oil saturation, average oil saturation, chemical tracer, drilling mud, investigate drilling fluid invasion, lombardi zone, aurignac zone, porosity
Subjects:
Formation Evaluation & Management, Tracer test analysis
Copyright 1987, Society of Petroleum Engineers
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