摘要:
A method for determining formation fluid pressure in earth formation surrounding a borehole wall uses a downhole probe coupled to a variable-volume cavity. The probe is driven into contact with formation at the borehole wall. The method includes expanding the volume of the cavity during a first period of time to establish fluid communication between tool fluid and formation fluid, by withdrawing a minimal amount of fluid from the formation. During a second period of time the tool pressure is allowed to equilibrate to formation pressure. When pressure equilibrium is established, formation fluid pressure is set equal to tool pressure. A preferred embodiment includes terminating expanding the volume of the cavity on detecting a break in the mud cake seal. An associated formation pressure tester tool includes an elongated body; a probe defining a formation fluid inflow aperture, an electromechanical assembly defining a variable-volume cavity, a pretest flow line coupling the aperture to the cavity, a pressure sensor coupled to the cavity; and downhole electronic means for controlling the expansion of the volume of the cavity.
摘要:
A method for determining formation fluid pressure in earth formation surrounding a borehole wall uses a downhole probe coupled to a variable-volume cavity. The probe is driven into contact with formation at the borehole wall. The method includes expanding the volume of the cavity during a first period of time to establish fluid communication between tool fluid and formation fluid, by withdrawing a minimal amount of fluid from the formation. During a second period of time the tool pressure is allowed to equilibrate to formation pressure. When pressure equilibrium is established, formation fluid pressure is set equal to tool pressure. A preferred embodiment includes terminating expanding the volume of the cavity on detecting a break in the mud cake seal. An associated formation pressure tester tool includes an elongated body; a probe defining a formation fluid inflow aperture, an electromechanical assembly defining a variable-volume cavity, a pretest flow line coupling the aperture to the cavity, a pressure sensor coupled to the cavity; and downhole electronic means for controlling the expansion of the volume of the cavity.
摘要:
Methods and related systems are described for improving component separations in chromatography through novel techniques. The improvements in separation is due primarily to the provision of differential acceleration of the components being separated. Various systems and methods for providing differential acceleration are described including: increasing the cross section of the column towards the column outlet, changing the thickness or other composition of stationary phase within the column, and providing a temperature and/or mobile phase velocity gradient along the column.
摘要:
A heat switch for remote self-contained gas chromatography is disclosed. The device mechanically separates a hot or cold reservoir from the chromatography column when heating or cooling is not needed. The column needs a cooling system to obtain initial temperatures below ambient. At other times the column needs to be heated to relatively high temperatures, during which time the cooling system is preferably detached. The heat switch allows for rapid temperature changes while minimizing the peak cooling power requirement.
摘要:
A self-contained micro-scale gas chromatography system that includes a plurality of gas chromatography components arranged on a micro-fluidic platform with nearly zero dead volume “tubeless” fluidic connections for the gas chromatography components. The micro-fluidic platform includes a plurality of flow channels that provide fluid flow paths for a sample, carrier gas and waste gas through and among the micro-fluidic platform and the plurality of gas chromatography components. The system may also include an on-board supply of carrier gas and on-board waste management, as well as a thermal management scheme making the system suitable for use in oil and gas wells and also other remote environments.
摘要:
A method of making a fiber optic accelerometer includes (a) drawing an optical fiber through a resin; (b) winding the resin coated fiber onto a disc mounted on an assembly having a central shaft; and (c) curing the resin-coated fiber. The optical fiber may be drawn through a resin by providing a container filled with a resin having an orifice therethrough and drawing the fiber through the orifice. The resin may be cured such that the fiber is bonded to the disc by curing the resin to the fiber and the disc at the same time.
摘要:
The disclosed jack assembly has an elongated structural beam of sufficient length to extend between and beyond the two rails of a railroad track to be supported on top of the rails. A compact power lift cylinder, in the form of a multiple-sleeve power cylinder, is connected to the beam; and a car engaging plate is coupled to the power lift cylinder, to be moved in a direction transverse to the beam. The silhouette of the beam, power lift cylinder and plate is low, when the power lift cylinder is contracted, to allow them to be fitted with clearance to a lifting position, under a railroad car with the beam extended across the track rails and the car engaging plate vertically aligned under the railroad car frame. The power lift cylinder has a power stroke sufficient to lift the overlying railroad car enough above the rails to remove the railroad car completely from one wheeled truck assembly, for replacement or the like. Blocks carried on the beam can be shifted against the raised car engaging plate, to hold it independently of failure of the power lift. A pumping system for the power lift is located laterally beyond the one side of the road car, with operating controls within easy reach of someone standing at this location. The pumping system can optionally be secured as a unitary part of the jack assembly, or as a separate unit. The jack assembly can be used from either side of the car, typically at a location between the wheeled truck assemblies supporting the car.
摘要:
A microfluidic system for performing fluid analysis is described having: (a) a submersible housing having a fluid analysis means and a power supply to provide power to said system; and (b) a substrate for receiving a fluid sample, having embedded therein a fluid sample inlet, a reagent inlet, a fluid sample outlet, and a mixing region in fluid communication with the fluid sample inlet, the reagent inlet, and the fluid sample outlet, and wherein the substrate includes a fluid drive means for moving the fluid sample through the substrate, and wherein the substrate interconnects with the housing. At least a portion of the fluid analysis means may be embedded in the substrate.
摘要:
A self-contained micro-scale gas chromatography system that includes a plurality of gas chromatography components arranged on a micro-fluidic platform with nearly zero dead volume “tubeless” fluidic connections for the gas chromatography components. The micro-fluidic platform includes a plurality of flow channels that provide fluid flow paths for a sample, carrier gas and waste gas through and among the micro-fluidic platform and the plurality of gas chromatography components. The gas chromatography components may include a micro-scale gas chromatography column that is implemented as a MEMS device and includes embedded heating and cooling elements. The system may also include an on-board supply of carrier gas and on-board waste management, as well as a thermal management scheme making the system suitable for use in oil and gas wells and also other remote environments.
摘要:
A method and apparatus for electrically interfacing between two or more distinct environments. The method and apparatus are directed to an electrical feedthru with one or more electrical transmission lines coated with one or more thin dielectric layers of material to insulate the transmission lines from a feedthru body. The dielectric layers may include a diamond-like carbon coating, which electrically insulates, but also thermally conducts. The use of thin dielectric layers facilitates smaller, more efficient electrical feedthrus. Therefore, the electrical feedthru may be used, for example, with MEMS devices. The electrical feedthru is not limited to any particular geometry, it may be adapted to fit between any two environments.