Waste Management For A Large-Scale Drilling Project

Abstract

Abstract In 1985 Shell Canada Limited completed the drilling of 209 wells as part of its Peace River Expansion Project (PREP). This projeel generated a combined total of 34 000 m3 of solid and liquid drilling wastes. Due to the volume of the wastes to be generated and because potassium chloride (KCl) salts would be present in the wastes, a waste management plan was required. The objectives of this plan were:Minimize the volume of wastes generated.Treat and re-use as much waste liquid in the drilling operation as possible.Dispose of all remaining wastes at project completion in an economical and environmentally acceptable manner. Prior to and during the project, various government agencies raised additional environmental concerns over those initially identified. To address these concerns, hydrogeological and environmental studies were undertaken. This paper discusses the approach used to develop and implement a waste management plan for a large-scale drilling project. Recommendations are provided to refine this plan for future projects. Introduction Over the past five years waste management has become a much more important aspect of the drilling operation. This has come about due to increased drilling sump disposal costs and increased environmental awareness. For Shell Canada Limited, the importance of having an effective waste management project in place for its Peace River Expansion Project (PREP) was very important due to the large volume of wastes expected to be generated as well as the environmental sensitivity of the area. Three rigs were used to directionally drill 209 wells from eight pads (Figs. 1 and 2). Each rig had centralized mud and power systems. Drilling time averaged 3.2 days per well. The pads were built on muskeg. All drilling wastes therefore had to be temporarily stored in surface tanks prior to transport to an off-lease site. Waste management has typically been considered by many as only that portion of our business which deals with the wastes remaining after the completion of drilling. On this project, the concept of waste management was expanded to also include that portion of our business which deals with wastes while they are being generated. The waste management program looked at not only the wastes that were produced but also the process by which they were produced. The over-all waste management program, therefore, focused on the areas of solids control, sump management, waste water re-use, waste water disposal and solids disposal. Waste Management Plan The waste management plan had the following main objectives:Minimize the volume of wastes generated.Treat and re-use as much waste liquid in the drilling operation as possible.Dispose of all remaining wastes at project completion in an economical and environmentally acceptable manner. To help meet the objective of minimizing the volume of wastes generated, a monitoring program was implemented. This involved monitoring the volume of wastes transported from each rig on a daily basis. This data was entered into a computer data system to be used for regular performance updates. This information was used to assist operations personnel in monitoring their waste management performance.