SPE Drilling & Completion
Volume 24, Number 3, September 2009, pp. 413-417

SPE-106829-PA

Treatment of Hydrocarbon-Based Drilling Waste Using Supercritical Carbon Dioxide

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DOI  More information 10.2118/106829-PA http://dx.doi.org/10.2118/106829-PA

Citation

  • Street, C.G., Tesche, C., and Guigard, S.E. 2009. Treatment of Hydrocarbon-Based Drilling Waste Using Supercritical Carbon Dioxide. SPE Drill & Compl  24 (3): 413-417. SPE-106829-PA. doi: 10.2118/106829-PA.

Discipline Categories

  • 2.5.4 Waste Management
  • 2.5.7 Remediation
  • 2.5 Environment
  • 2 Health, Safety, Security, Environment and Social Responsibility
  • 1 Drilling and Completions

Summary

Nonaqueous drilling fluids are essential in challenging drill operations. Their use, however, requires special treatment and disposal because of their potential for environmental damage. In light of increasing costs for common treatment technologies and ever-tightening environmental legislation, alternative treatment technologies are being sought by the drilling industry. Supercritical fluid extraction is one such technology that employs a substance higher than its critical pressure and temperature as a solvent.

In this paper, the results are presented of a study using supercritical carbon dioxide to treat synthetic based drilling waste. Unlike typical supercritical fluid extraction studies in which the process is optimized using changes in pressure and temperature, this study was undertaken to improve the extraction of hydrocarbons from drilling waste by increasing the supercritical fluid solvent to waste ratio. Efforts focused on improving supercritical fluid/drilling waste contact, eliminating system clogging with waste solids and minimizing solids carryover. Alterations to the waste using additives and alterations to the vessel both led to an increased amount of waste being treated effectively using the same amount of solvent. Optimization of the process yielded efficiencies as high as 97%. Also, it has been determined that the extracted hydrocarbons are unchanged by the supercritical fluid extraction process. This result suggests that the collected hydrocarbons may be reused in the drilling process, resulting in significant cost savings to the industry.

Introduction

In rotary drilling for oil and gas, drilling fluids are essential to clean the wellbore and to lubricate the drill bit. Nonaqueous-based drilling fluids (NADFs) are thought to be superior over water-based drilling fluids because of their higher natural lubricity and lower reactivity with clays and shales [Canadian Association of Petroleum Producers
(CAPP) 2001; Melton et al. 2004]. As such, they are often necessary for challenging drill operations. However, they are much more expensive and, because of their hydrocarbon content, the wastes they generate must be handled and disposed of carefully.

Numerous techniques have been developed to treat the wastes generated from drilling with NADFs. These techniques include bioremediation technologies, such as landfarming and cleaning technologies (e.g., incineration or solvent washing) (Saintpere and Morillon-Jeanmaire 2000). As environmental legislation becomes
increasingly more stringent and the cost of common treatment techniques increases, the drilling industry seeks out new approaches to the treatment of NADF drilling waste (Minton and McGlaughlin 2003).

© 2009. Society of Petroleum Engineers

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History

  • Original manuscript received: 1 October 2007
  • Meeting paper published: 5 March 2007
  • Revised manuscript received: 31 August 2008
  • Manuscript approved: 11 September 2008
  • Published online: 19 February 2009
  • Version of record: 28 September 2009