Pneumatic Conveying of Model Drill Cuttings - Pilot Scale Experiments and Simulations

Abstract

Abstract The offshore drilling operations generate huge volume of drill cuttings. Rig site transfer of cuttings can be a challenge both if pneumatic conveyors or screw conveyors are used. Especially, wet powder is a challenge since the particles become too sticky for easy handling or too dry for acting like a slurry. This paper presents the preliminary results of a scientific investigation aimed to study transport properties and storage criterion of dry and partially-moist solids drill cuttings. Model materials have been tested in pilot scale pneumatic conveying rigs and CFD simulation on particle conveying has been performed in parallel. The pilot scale tests have been conducted for the sand particles in the size range of 0.1 – 3 mm diameter under the air flow rate of 13-23 ms-1 The simulations were carried out using multiphase particle-in-cell method (MP-PIC) for dry particles that are having particle size distribution in the range of 0.3-3 mm diameter. Pressure drop in a horizontal section is studied and it was observed that at a minimum pressure drop and a minimum specific power requirement is reached when decreasing the superficial air velocity. This region can be considered as the economical region for operation. For the considerd particle size this region was obtained at the air velocity of 16-19 ms-1 for a horizontal pipe section with 81.2 mm diameter. In the simulations, the predicted pressure drops in 15-22 ms-1 velocity range are in good agreement with experimental results. The combination of pilot scale pneumatic conveying tests and simulations of dry drill cuttings provide a platform to evaluate and predict pneumatic conveying parameters for partially-moist drill cuttings.