Abstract: A method of determining an amount of dissolved gas in a fluid sample is disclosed. The method includes hydraulically confining and expanding the sample while measuring pressure and volume. A first volume and pressure are determined at which the rate of change in pressure with respect to volume deviates from a linear relationship. A second volume and pressure at which continued expansion of the fluid causes substantially no change in pressure is determined. The first pressure and volume are extrapolated by the linear relationship to intersect an extrapolation from the second volume and pressure at no change in pressure, thereby determining a bubble point comprising a bubble point pressure and a bubble point volume. A third pressure corresponding to measured pressure of the fluid sample at the bubble point volume is determined.

Abstract: A method of determining the volume of a fluid sample withdrawn from an earth formation penetrated by a wellbore is disclosed. The method includes the step of positioning a formation testing tool adjacent to the earth formation. The tool includes a probe which can be selectively placed in hydraulic communication with the formation and excluded from hydraulic communication with the wellbore. The probe can be in hydraulic communication with a pressure transducer. The tool includes a sample chamber selectively placed in hydraulic communication with the probe. The chamber includes means for measuring the volume of the chamber and means for selectively controlling the volume of the chamber.

Abstract: An apparatus for withdrawing fluid from an earth formation comprising an elongated housing, a first inflatable elastomeric seal adapted to expansively fill an annular space between the housing and the wall of a wellbore. The seal includes axially spaced seal lips protruding from a surface of the seal. The seal lips circumscribe the seal and define a flow channel therebetween. The flow channel includes radially spaced filler blocks which divide the channel into radial segments. Each segment further includes a flow port. The apparatus includes means for inflating the seal. The apparatus includes valves connected to each of the flow ports for connecting selected flow ports to an intake of a fluid pump and connecting selected other flow ports to a discharge port of the pump. The pump is operable in conjunction with the valves to withdraw fluid from selected flow ports and to discharge fluid into other flow ports.

Abstract: The present invention is a sample tank for storing and transporting a fluid sample withdrawn from an earth formation by a formation fluid sampling tool. The sample tank includes a storage cylinder adapted to withstand high internal pressure. The storage cylinder is selectively hydraulically connected to the sampling tool for conducting the fluid sample into the storage cylinder. A fusible metal substantially surrounds the storage cylinder. The fusible metal has a melting temperature not more than the temperature of the fluid sample, so that solidification of the fusible metal maintains the fluid sample substantially at the melting temperature of the fusible metal during solidification of the fusible metal as the tool is withdrawn from the wellbore and cooled. The fusible metal is surrounded by an outer housing which contains the fusible metal when it is in a liquid state.

Abstract: A method and apparatus for conducting in situ tests on a subsurface earth formation of interest which is traversed by a wellbore. A wireline formation testing instrument is positioned at formation depth and a sampling probe thereof is extended into fluid communication with the formation and isolated from wellbore pressure. Utilizing a hydraulically energized double-acting bi-directional piston pump and by valve controlled selection of pumping direction testing fluid such as completion fluid may be pumped into the formation through the sampling probe either from fluid reservoirs of the instrument or from the wellbore. After reversing the operating and control valving of the pump and instrument, the piston pump is utilized to extract formation fluid from the formation and pump it to sample tanks of the instrument, pump it into the wellbore or subject it to controlled pressure for real time formation testing and for formation characterization.

Abstract: A method and apparatus for downhole formation testing is provided for acquisition of a phase intact sample of connate fluid by direct or indirect pumping for filling of pressure containing sample tanks that are removable from a formation testing and sampling instrument for phase intact transportation to a laboratory facility. One or more fluid sample tanks contained within the instrument are filled with connate fluid samples in such manner that during filling of the sample tanks the pressure of the connate fluid is maintained within the predetermined range above the bubble point of the fluid sample. The sample tank incorporates an internal free-floating piston which separates the sample tank into sample containing and pressure evacuation chambers. During indirect pumping a positive displacement piston pump draws fluid from the pressure evacuation chamber and permits formation pressure to shift the separator piston as the first variable volume chamber is filled with a connate fluid sample.

Abstract: A method and apparatus is provided for use in connection with a downhole formation testing instrument for acquisition of a phase intact sample of connate fluid for delivery via a pressure containing sample tank to a laboratory facility. One or more fluid sample tanks contained within the instrument are pressure balanced with respect to the wellbore at formation level and are filled with a connate fluid sample in such manner that during filling of the sample tanks the pressure of the connate fluid is maintained within the predetermined range above the bubble point of the fluid sample. The sample tank incorporates an internal free-floating piston which separates the sample tank into sample containing and pressure balancing chambers with the pressure balancing chamber being in communication with borehole pressure.

Abstract: A membrane pack is constructed, which includes a highly porous carrier sandwiched between a pair of membrane structures that must be kept continuously wet, the pack having a hole and being sealed around the hole to prevent the passage of polluting liquid lying in the hole, into the porous carrier of the pack. The membrane pack is constructed by impregnating the carrier with a flowable polymer which can solidify, to leave a thin layer of the polymer on either surface of the carrier, and by then welding the polymer layers to membranes at either face of the carrier. Ultrasonic welding of the membrane structures to the carrier is performed while the membrane structures are wet, the ultrasonic welding dissipating moisture lying at the interface between the carrier and membrane structures to permit even hydrophilic polymers to be utilized.

Abstract: Apparatus is provided for collecting a plurality of samples of fluids in earth formations traversed by a well bore. The sampling apparatus includes an elongated body member adapted to carry an extensible and retractible fluid admitting probe which is selectively placed in sealing engagement with potentially producible earth formations. The fluid admitting probe is coupled to a fluid passage which is selectively placed into fluid communication with a fluid sample collection chamber. A selectively controllable pressure control system located in the fluid passage intermediate the fluid admitting probe and the sample collection chamber allows the flowing pressure within the formation fluid sample line to be maintained at any selected pressure level functionally related to hydrostatic pressure during fluid sample collection.

Abstract: A fluid purification apparatus of the type which includes a stack of membrane packs and a stack of gaskets located at the peripheral portions of the membrane packs to keep them separated from one another, wherein the gaskets have outer lands bearing on one another and surrounding the membrane packs, inner lands pressing against the faces of the packs to seal against them, and elongated bendable middle gasket portions connecting the inner and outer lands to allow the inner lands to adjust position so as to compensate for variations in thickness of the membrane packs.