Unique Drilling Waste Handling and Transport System Offers Advantages to Drilling Operations and Assists Operators in Acheiving Safety and Environmental Compliance

Abstract

Abstract Since the introduction of various environmental regulations limiting or banning the discharge of various types of drilling fluids and associated drill cuttings globally, there has been considerable growth in what has become known as "zero discharge" or "ship to shore" operations. In these operations drill cuttings and associated waste fluids are collected on the rig in cuttings boxes (also known as skips) and then sent back to shore for disposal or treatment prior to disposal. In other situations, depending on local legislation, drill cuttings are collected and then transported to a grinding and slurrification package prior to injection downhole.1,2 In addition, even where the discharge of cuttings offshore is still permitted, there is often now a requirement to collect and transport drill cuttings on the rig for secondary treatment such as cuttings dryers that reduce the amount of drilling fluid associated with cuttings prior to discharge.3 These types of operations typically create operating challenges and additional costs associated with the required additional equipment, manpower, rig space, and in some cases, can even require significant rig modifications. Various technologies have been used to date for the collection and transportation of drill cuttings. These include screw conveyors, vacuum systems, positive displacement pumps and pneumatic systems.4 The benefits and limitations of all of these systems are discussed in this paper with emphasis on the testing and performance of a positive displacement drill cuttings transfer system previously developed by Halliburton. Depending on the technology used, there are safety and environmental risks associated with "ship to shore" operations and the use of cuttings boxes, such as significantly increased crane operations, housekeeping and deck space issues, transfer of wastes to boats or barges, the use of screw conveyors or high pressure pumping equipment and increases in waste volumes generated and eventually disposed of.