Innovative Treatment Alternatives for Oily Wastes Generated During the Exploration and Production of Oil and Gas

Abstract

Abstract The Exploration and Production (E and P) of oil and gas generates significant quantities of oily wastes, including oily drill cuttings, spent oil-based drilling muds, crude oil contaminated soils, crude oil tank bottoms, and reserve pit oily sludges. As E and P companies have become increasingly aware of environmental liabilities (past, present, and future) associated with E and P operations, they have sought alternatives to their present oily waste management practices. This paper discusses two innovative treatment alternatives for E and P oily wastes, thermal desorption and biological liquid/solids treatment. These two technologies are fully developed and have just recently been demonstrated at full-scale on refinery oily wastes and at pilot-scale on E and P oily wastes. Results of pilot-scale testing indicate that biological liquid/solids treatment of E and P oily waste can significantly decrease the oil and grease (O and G) fraction of the waste in a reasonable time period and for a reasonable cost (less than $75/yd3). O and G half-lives were measured at less than 15 days. Thermal desorption can reduce O and G to less than 1% in oily drill cuttings at a cost of less than $100/yd3. Both technologies are currently being applied to the treatment of refinery oily wastes. An overview of both treatment technologies is presented in this paper, including process fundamentals, operational considerations, and results of recent pilot-scale testing on E and P oily wastes. Introduction The Exploration and Production (E and P) of oil and gas results in the generation of three major groups of wastes known as produced water, drilling wastes, and associated wastes. As shown below, the overwhelming portion is produced water. % of Total Produced waters 98.0 Drilling wastes 1.9 Associated wastes 0.1 100 Produced waters are primarily disposed in underground injection wells or used for enhanced oil recovery. Unlike produced waters, drilling and associated wastes are not treated uniformly but treated and disposed in a variety of ways throughout the oil and gas producing states. Techniques for handling these wastes include:*land spreading (land farming)*solidification and burial*road spreading