Control and regulation of the density of technical fluids during their transportation by sea specialized vessels

Abstract

The object of research is the process of transporting drilling slurry through specialized marine vessels of the Platform Supply Vessels class. The subject of research is the sedimentation stability of the drilling slurry along the height of the cargo tank, which is proposed to be defined as a relative change in vertical density near the surface and bottom of the cargo tank. The studies were carried out on a specialized sea vessel with a displacement of 7320 tons. The design of the vessel provided for the reception and transportation of drilling slurry in four cargo tanks located on the port and starboard sides of the vessel. It has been experimentally established that during the 48-hour transportation, the density of the drilling slurry in the bottom part increases to 19.7 %; decrease in density on the surface – up to 7.8 %; decrease in the sedimentation resistance of the drilling slurry along the depth of the cargo tank – up to 29.85 %. A variant of modernization of the drilling slurry transportation system by installing additional circulation pumps providing forced circulation of the drilling slurry between cargo tanks is proposed. By using programmable microcontrollers (performing turning on/off the circulation pumps), it is possible to provide the following conditions for transporting the drilling fluid: an increase in the density of the drilling fluid in the bottom part up to 0.3 %; decrease in density on the surface – up to 0.25 %; decrease in the sedimentation resistance of the drilling slurry along the depth of the cargo tank – up to 8.01 %. It has been experimentally established that the creation of additional circulation and automatic support of the sedimentation resistance of the drilling fluid in the range of 2–7 % contributes to: – increasing the relative performance of cargo pumps from 38–55 % to 92–96 %; – reducing the time of pumping drilling slurry from cargo tanks to the drilling platform from 7.1 to 3.2 hours; – maintaining the technical condition of equipment, pipelines and elements of the drilling slurry transportation and pumping system.