Pollut-Eval: An Innovative Tool For Direct Hydrocarbon Characterization In Oil Base Mud & Cuttings

Abstract

Abstract Throughout the world, the drilling process generates a huge variety ofcontaminated solid waste. The environmental impact of these side products depends on their composition and concentration but also on the employed drilling technologies, based on water base mud (WBM) or oil base mud (OBM). The various local and international Guidelines will gradually ban thedischarge into the sea of these contaminated drilling waste. The OSPAR 2000/3 decisions will soon prohibit their disposal into the seaand will recommend a "zero %" discharge of organic based drilling fluids. With the emphasis placed on environmental safety, the oil companies aredeveloping economical methodologies to clean oil contaminated field waste, suchas cuttings or used drilling muds. One of the major challenge is to developsensitive analytical tool to measure in a short time low oil content in a greatvariety of mineral matrix without major interference. In this framework, this paper provides answers concerning the problem of quantification of low oil content in complex solid waste. A study has been performed to demonstrate the ability of the Pollut-Eval method to characterize and quantify hydrocarbon contamination without any pretreatment. In a firststep, analytical results of pure hydrocarbon cuts commonly used in drillingmuds (iso and n-paraffin, a olefin, ester and diesel cuts) will be presented to demonstrate the qualitative and quantitative efficiency of the method. In a second step, evaluation of the total organic content of various drilling muds will be compared to their hydrocarbon concentration to demonstrate that no major interference occurred in the characterization or quantification of these petroleum cuts despite the various and complex mudformulations. In a last step, Pollut-Eval residual oil content (ROC) and total organic carbon (TOC) of undersea discharged cuttings sampled at 200 m depth(more or less distant from an offshore rig) will be presented and compared to capillary gas phase chromatography results. As a conclusion, Pollut-eval performance will be discussed and compared to other methods commonly used in oil industry: global carbon organic determination by catalytic oxidation and retort kit distillation. Introduction For a few years, the recent international recommendations and Guidelinesconcerning the final disposal of drilling fluids have obliged the drillingindustry to serious control of waste release. To be efficient, the monitoring methodologies should be applied to alldrilling formulations whatever their hydrocarbon or organic composition. At theend of the drilling process, the efficiency of the solid waste post-treatmentshould also be taken into account. Because the drilling activities are producing huge amount of contaminatedwaste in the form of cuttings (2%) or hydrocarbon based drilling mud (89%), oil companies are seeking economical methodologies to clean up solid waste producedas by-products. Whatever the technology chosen in clean up operations, the needof an accurate monitoring is stringent and should be included in the globalcost evaluation of the process (gravel to grave concept). As a "zero %" discharge becomes more and more evident, 2 main technological options will be available in the next years before the final disposal of thedrilling waste:ship to shore for further treatments such as bioremediation, incineration, solvent washing or thermic desorption.cuttings reinjection techniques