The complete Kvaener Booster Station has undergone extensive underwater testing in its test tank in the two-phase laboratory at Tiller, Trondheim, Norway.
The whole range of steady state performance testing up to 11 000 Barrels/Day of liquid and/or 7.0 million SCF/Day of gas has proved the basic concept.
Additionally, significant development of the process control system has resulted in understanding and excellent control of both upstream slug flow and pressured low variations from a simulated well scenario and also the downstream pressure/flow variations representing long, undulating flow lines followed by a riser. Handling of foaming fluids has been achieved, including exceptional foam into the compressor.
The paper presents a brief description of the KBS, the test facilities and the results of the testing. It considers the implications to the user/operator, together with the conclusions from the post-testing inspection.
The Kvaener Booster Station is now considered to k qualifield for use on a subsea application.
The function of the KBS is to increase the pressure in a flowing hydrocarbon stream. As such it is a multiphase pump. The KBS however, separates the flow into a pumpable liquid and a compressible gas. The two phases are then increased in pressure in separate pump and compressor, both electrically driven, and both using known and proven technology. The resulting streams at higher pressures can then be recombined into one flowline or sent in two separate flowlines to the receiving facility. The KBS is divided into three main modules; separator and cyclone scrubber module, pump module; and compressor module. These can be individually sized and configured to suit the application. Figure 1 is a cutaway section of the first KBS, which has a nominal capacity of 10000 Barrels/Day of liquids and 12000 ACF/Hr (or approximately 4.5 million SCF/Day) of gas. The whole KBS tits inside the standard API guide-post spacing, is about 12 meters (40 fi) high and weighs about 50 tonnes as shown in figure 1.
The modules are mounted one above the other with the pump at the bottom, the separator in the middle and the compressor at the top.
Although the KBS at first sight seems complex, it is in fact very simple compared to similar topsides equipment and even the apparently simpler multiphase pump, when all auxilliary equipment has been added. All non-essential equipment has been eliminated. The remaining equipment has been configured in detail by some of Europe's leading suppliers. Only through these routes has it been possible to build in the necessary level of inherent reliability. Maximum use has been made of the subsea environment of water under pressure, and the fact that it is inaccessible.
