UK flowmeter specialist Litre Meter has shipped 43 VFF positive displacement flowmeters to Singapore-based Oakwell Engineering.
The meters will be used in the flow measurement of wax dispersants and pour point depressants (PPD) on a chemical injection skid for the Al Jalilah field off Dubai. They measure the flow of chemicals to an accuracy of 0.5 per cent, making it possible to control their use to a very high tolerance.
Wax dispersants are used to break apart and prevent the reformation of hydrocarbon sludge deposits and improve fluid flow by reducing the viscosity of the fluid. PPDs are used to reduce the viscosity of oil and to maintain flow rate by preventing the build-up of wax crystals at low temperatures.
Sludge deposits are typically composed of varying concentrations of hydrocarbon, asphaltene, paraffin, water and inorganic materials. They are commonly found in storage tanks and vessels, production and transportation pipelines, process systems and hydrocarbon-producing formations where they have an adverse effect on the flow of crude oil from the well head.
Loss of production caused by blockage is high cost, so protecting pipework from the formation of asphaltene and hydrocarbon deposits and reducing the pour point (the lowest temperature at which oil will easily flow) are major concerns in offshore operations. Flow assurance strategies provide protection during normal operation, start-up and shutdown.
Litre Meter VFF positive displacement flowmeters measure the correct amount of dispersant and depressant chemicals needed to provide flow rate assurance. Accurate measurement of costly chemicals means that oil companies can keep costs down while ensuring that optimum flow is maintained to ensure continued production.
Oakwell selected Litre Meter VFF meters because they are versatile and operate accurately at the required flow rates and pressures – in this case 10 litres per hour (l/h) at 120 bar and 13 l/hr at 190 bar. In addition, Litre Meter was able to deliver instruments with integral head-mounted display with the appropriate ATEX certification.
The VFF flowmeter is suitable for measuring liquids at pressure ratings up to 4,000 bar (60,000 psi) and flow rates from 0.0004 l/m (0.5 litres per day) to over 270 l/min. It is of intrinsically safe design and manufactured to operate reliably at temperatures ranging from -40 to 100°C.
Litre Meter CEO Charles Wemyss said: “Litre Meter’s VFF flowmeter is ideally suited for use in the oil and gas industry and in particular for low flow/high pressure applications.
“Years of experience in chemical injection applications onshore and offshore have confirmed the instrument’s capability to reliably measure fluids under extreme conditions of both temperature and pressure.”