Introduction 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 includescrew 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 positivedisplacement 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. In this paper a new system for handling drill cuttings in zero discharge and other drilling waste management operations is described. This system has been shown to handle all types of drill cuttings from dry cuttings to slurries and even whole drilling fluids and has features that overcome many of the limitations of other systems currently used in the industry to transfer cuttings. Field experience and case histories show that this system is capable of collecting and transferring drill cuttings over the distances typically required on drilling rigs (and further if necessary) and at the rates required to keep up with drilling operations without many of safety concerns and limitations of other systems, without increasing volumes of waste generated and with minimal footprint and rig modifications required. Properties of Drill Cuttings Perhaps the most significant challenge to developing technology to transfer drill cuttings is that drill cuttings are very inconsistent by nature, ranging from high liquid content slurries to almost dry depending on drilling rates and conditions, drilling fluids used and solids control equipment efficiency. The drilling rig's solids control equipment is designed to separate the drilled formation from the drilling fluid based on either the size or density of the solid particles. The drilling fluid can then be re-used. However 100% separation is not possible with current technology. Instead drill cuttings are generated with a significant fraction consisting of drilled formation and other solids such as commercial clays and weight materials, and a fraction of drilling fluid associated with those solids. The relative percentage of each will vary greatly. Depending on the relative fraction of solid to liquid and solid particle size, drill cuttings can behave as either a liquid (high liquid content), a paste (intermediate liquid content) or as a solid material such as sand or gravel (low level liquid content). A range of the physical properties of drill cuttings is proposed in Table 1, but this is only to be taken as a guide.
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