Development of a method for maintaining the performance of drilling fluids during transportation by Platform Supply Vessel

Abstract

The object of research is the process of transportation of drilling fluid used for lubrication and cooling of drilling equipment of offshore oil production platforms. The subject of the study is the stratification of the density of the drilling fluid along the height of the cargo tank in which it is transported. The technology of transportation of drilling fluid on the Platform Supply Vessel is considered. A problematic point in ensuring this process is that during the transportation of drilling fluids, due to the action of gravitational forces on organic and inorganic compounds in their volume, there is a latent change in their dispersion over the volume of the fluid. This leads to the stratification and stratification of the fluid density along the height, as well as to the formation of sediments at the bottom of the cargo tanks, in which the drilling fluid is transported. The study is aimed at developing a technology that maintains a constant value of the density of the drilling fluid along the depth of the tank in which it is transported. The studies were carried out in the vessel system for transporting drilling fluid of a specialized marine vessel of the Platform Supply Vessel type with a deadweight of 5850 tons. It is experimentally established that for a transportation time of 6–36 hours, the density stratification of the drilling fluid is 3.04–32.04 %. As a method that ensures the minimum stratification of the density of the drilling fluid during its transportation, it is proposed to use an additional X-shaped circulation of the drilling fluid in the volume of adjacent cargo tanks. Studies have confirmed that the density stratification over a time period of 6–36 hours decreases to a range of 2.30–9.01 %. The complex use of additional X-shaped circulation and simultaneous air supply to the bottom of the cargo tank provides a density stratification value of 0.73–2.93 %. The proposed technology was tested on a specialized seagoing vessel of the Platform Supply Vessel type with a deadweight of 5850 tons and can be used on offshore vessels that ensure the operation of offshore oil production platforms.