Abstract: The accuracy of a measurement of the composition of a multiphase sample containing crude oil and water is improved by pouring the sample into a bottle shaped container (1), which is dimensioned such that the oil-water interface (4) is located in an upper portion (3), which forms a bottleneck that has a smaller cross section than a lower portion (2) of the container (1), which lower portion (2) has a substantially frusto-conical shaped intermediate section (8) contiguous with the upper portion (3) that allows accurate water cut measurement even if the oil-water interface is located within the intermediate section (8).

Abstract: A method for stepwise varying fluid flow in a well utilizes a plurality of downhole valves which have orifices of different sizes in the valve bodies, so that fluid flow can be varied by partially closing one or more valves. The method may be used for testing gas wells such that the wellbore storage delays caused by gas compression and/or expansion in the production tubing are minimized.