Water Injection

FLUXUS®, more than a match for erosion Water injection is a common way to extend reservoir life through intelligent well management.

In order to raise the reservoir pressure and improve the production rate, sea water is injected into the well. The injected water quantities are monitored by flow meters and transmitted to the process control system.

The water injection takes place in two steps. Firstly the booster pumps suck the water out of the reservoir's water tank to create a slight admission pressure of approximately 15 bar. The injection pumps need this pressure in order to work cavitation free. Secondly the injection happens in 254 mm (10 inch) pipes made of 25.4 mm (1 inch) thick duplex steel, where pressures of about 300 bar (4,350 psi) can be reached during the process.

Measuring such injection rates accurately can be challenging. The high pressure, high velocity water typically causes severe erosive wear to traditional flow meters, which rely on parts protruding into the pipe.

One European producer found this out the hard way on a North Sea platform. Erosion and deposits caused the precision of differential pressure flow meters in the water injection lines to decrease continuously.

A non-invasive flow measurement with the FLUXUS® ADM7907 was the ideal solution. The installation of the meters can take place without interrupting the production and without cutting into the pipe. The transducers are simply clamped onto the pipe and do not cause any pressure loss. Since they do not come in contact with the medium, they are not subject to wear.

These advantages make the system a perfect solution for retrofit installations. The benefits are also important when considering new installations, taking the system’s comparably low weight and non-existent pressure loss into account.

The company reports that its FLUXUS® ADM7907 flow meters require little or no maintenance yet are completely immune from performance fall-off caused by the high velocities and pressures found in water injection.

FLUXUS® overcame the following challenges:

• Thick walls in excess 40 mm (1.58 inch)

• Exotic pipe materials (Super Duplex)

• No drift due to wear

• SS 316 Ti version fully compliant to NORSOK