Abstract: Apparatus and a method are provided for bringing a well-fluid sample in a well through a sampling device which is in fluid communication with the apparatus. The apparatus includes: a dump chamber for receiving the well-fluid sample; a first hydraulic piston arranged in a first cylinder housing; a second hydraulic piston arranged in a second cylinder housing; a piston rod for mechanically connecting the first piston to the second piston to form a piston arrangement, the dump chamber being defined by the first piston and a portion of the first cylinder housing. The apparatus further includes at least one holding device arranged to switch between an active position, in which the piston arrangement is held fixed against movement, and an inactive position, in which the piston arrangement is allowed a movement relative to the cylinder housings.

Abstract: Apparatus and a method are provided for bringing a well-fluid sample in a well through a sampling device which is in fluid communication with the apparatus. The apparatus includes: a dump chamber for receiving the well-fluid sample; a first hydraulic piston arranged in a first cylinder housing; a second hydraulic piston arranged in a second cylinder housing; a piston rod for mechanically connecting the first piston to the second piston to form a piston arrangement, the dump chamber being defined by the first piston and a portion of the first cylinder housing. The apparatus further includes at least one holding device arranged to switch between an active position, in which the piston arrangement is held fixed against movement, and an inactive position, in which the piston arrangement is allowed a movement relative to the cylinder housings.

Abstract: Apparatus and a method are provided for bringing a well-fluid sample in a well through a sampling device which is in fluid communication with the apparatus. The apparatus includes: a dump chamber for receiving the well-fluid sample; a first hydraulic piston arranged in a first cylinder housing; a second hydraulic piston arranged in a second cylinder housing; a piston rod for mechanically connecting the first piston to the second piston to form a piston arrangement, the dump chamber being defined by the first piston and a portion of the first cylinder housing. The apparatus further includes at least one holding device arranged to switch between an active position, in which the piston arrangement is held fixed against movement, and an inactive position, in which the piston arrangement is allowed a movement relative to the cylinder housings.

Abstract: A method for testing petroleum or water wells. A tool is secured to a tubing and run into the well and to the reservoir zone to be explored. An upper and a lower seal isolate the reservoir zone. A piston is run into the tubing and pumped down to the tool. When sampling is to take place, a valve is opened and the reservoir fluid, together with drilling fluid filling the well, is allowed to enter the tool while displacing the piston. At the same time, measuring is carried out to identify a tracer added to the drilling fluid. When the tracer no longer can be traced, the drilling fluid contaminated reservoir fluid is displaced out of the tool by the piston and clean reservoir fluid is allowed to enter the tool. The invention also relates to an apparatus for practising the method.

Abstract: A method for testing petroleum or water wells. A tool is secured to a tubing and run into the well and to the reservoir zone to be explored. An upper and a lower seal isolate the reservoir zone. A piston is run into the tubing and pumped down to the tool. When sampling is to take place, a valve is opened and the reservoir fluid, together with drilling fluid filling the well, is allowed to enter the tool while displacing the piston. At the same time, measuring is carried out to identify a tracer added to the drilling fluid. When the tracer no longer can be traced, the drilling fluid contaminated reservoir fluid is displaced out of the tool by the piston and clean reservoir fluid is allowed to enter the tool. The invention also relates to an apparatus for practising the method.

Abstract: The invention relates to a method for use in sampling, flow measuring, quantity gauging, or possibly other analysis performed in reservoir fluid found in a ground formation. An object of the invention is to perform the sampling, flow measuring and quantity gauging or the remaining analyses in situ on stabilized reservoir fluid that contains a negligible amount drill fluid. Analysis is possible by sealing off an area of the well at the hydrocarbon carrying layer and passing a volume of reservoir fluid into a drill string for analysis by accessories located in the drill string. After the analyses are performed, the reservoir fluid is returned to the hydrocarbon carrying layer.

Abstract: When conducting in situ measurements etc. of the properties/parameters of a reservoir fluid, possibly in connection with analyses,use is made of a measuring instrument/apparatus-containing casing (7) at the upstream end of a drill string (4), which casing has a combined inlet/outlet facing the hydrocarbon-containing layer (2) of the reservoir and is in fluid communication with the bore of the drill string (4), in which is disposed a reciprocally sliding piston (17), the top of which—opposite the side for inflow of reservoir fluid (RF)—may be acted on by pressure through a pressurisable fluid (water or N2) in order, on completion of the measurements, to force the reservoir fluid (RF) previously accommodated in the bore of the drill string back into the oil-containing layer of the reservoir.