Minimizing Oil and Gas Wastes
Waste minimization during drilling operations.
The state of Texas has produced a document Waste Minimization in the Oil Field that provides a general overview of waste minimization techniques for wastes arising from oil and gas operations, including drilling operations. The document also provides case studies of successful waste minimization projects and a bibliography of useful technical references. The document includes dozens of examples of alternative drilling practices, such as:
- Product substitution. Replacing conventional, toxic products with less toxic, yet effective, substitutes. For example, companies are substituting low toxicity glycols, synthetic hydrocarbons, polymers, and esters for conventional oil-based drilling fluids. The use of these substitutes eliminates the generation of oil-contaminated cuttings and other contamination by the oil-based fluid and decreases concerns related to site clean-up when the well is abandoned. Drilling engineers have published numerous technical papers that describe the successful application of substitute drilling fluids. In many instances, this substitution has resulted in significant cost savings. Similarly, companies have designed alternatives to the conventional water- and chemical-based hydraulic fracturing techniques, by substituting carbon dioxide for the more common and more toxic fracing fluids.
- Process or procedural modifications. For example, in the past few years the drilling industry has improved the technology of slim hole drilling. If feasible, slim hole drilling reduces the volume of wastes (e.g., drilling fluid and the drill cuttings) produced during drilling. The total cost of a slim hole drilling operation may be considerably less than for conventional hole sizes, and smaller casing is required, which may help reduce the total cost of the operation.
- Reduction in water use. For example, companies can reclaim water from waste drilling fluids by using mechanical or chemical separation techniques such as large bowl centrifuges, hydrocyclones, and/or chemical flocculants. The reclaimed water may then be reused, thus reducing the demand on, and cost of, new water sources. Dewatering of wastes may also result in a reduction of the volume of drilling waste to be managed, thus saving waste management costs, easing site closure concerns and costs, and reducing future potential liability concerns.
- Preventative maintenance. For example, chemicals and materials should be stored so that they are not in contact with the ground (e.g., stored on wooden pallets), or exposed to the weather. There should be secondary containment in the case of spills. All drums and containers should be kept closed except when in use. It is very important that all chemical and material containers always be properly labeled so that their contents may be identified at any time. Proper storage and labeling of containers allows quick and easy identification and classification of released chemical or material in the event of a leak or rupture. In some instances, that could save hundreds of dollars in soil sampling and laboratory analysis costs.
- Recycling. For example, the cost of closing a drilling site is increased if waste drilling fluid in a reserve pit must be dewatered and/or stabilized prior to closure. An alternative is to recycle or reuse the waste drilling fluid, e.g., in another drilling project. One company designed a multi-well drilling project where the same drilling fluid was used for drilling each successive well. The result was significant cost savings and greatly reduced waste management concerns. Another cost effective alternative for reuse of waste drilling fluid is in plugging or spudding of other wells.
Pollution Prevention and Waste Management
- Drilling Waste Management Information System is an online resource created by the Argonne National Laboratory and industry. It contains technical and regulatory information on standard and “optimal” practices for managing drilling wastes.
- A Pollution Prevention Opportunities Guide for the Oil Field Service Industry. Alaska Department of Environmental Conservation Pollution Prevention Office.New Mexico Energy, Minerals and Natural Resources Department's two-volume handbook on Pollution Prevention - Best Management Practices for the Oil and Gas Industry.
- The Railroad Commission of Texas (state regulatory body) has produced a Minimization in the Oil Field Manual; and a program devoted to waste minimization in the oil and gas industry; and a page of links to other waste minimization resources for the oil and gasindustry.
- U.S. Environmental Protection Agency Oil and Gas Industry Sector Notebook describes pollution prevention opportunities.
- Best Management Practices for Oil Exploration and Extraction produced by the Illinois office of the EPA.
- Southwest Pollution Prevention Center, Gas and Oil Hub provides information on oil and gas pollution prevention alternatives for all stages of oil and gas development, and it lists of wastes associated with various stages of oil and gas operations.