摘要:
Several optical probes useful in downhole applications are provided. A first probe has a tip in the form of a cubical corner with the diagonal of the cubical corner aligned with the axis of the probe. A second probe has a tip formed in a 45° cone. In these designs, light will bounce respectively three times or twice, but still retain the same orientation. To facilitate drainage, the very tip of the probe may be rounded. Both designs also provide a probe with a large numerical aperture and both are useful for detecting reflectance and the holdup of a multiphase fluid. A third probe uses (hemi)spherical or paraboloid probe tip. The third probe tip has a small numerical aperture and is useful for detecting fluorescence and oil velocity. In all three embodiments, the base behind the probe tip may be tapered to facilitate fluid drainage.
摘要:
A formation testing probe assembly comprising an elongated packer having a surface configured to be urged by the probe assembly towards a wall of a wellbore extending through the formation. The formation testing probe assembly further comprises a plate embedded in the elongated packer and including a central structural portion extending along a centerline of a substantial length of the plate, wherein the central structural portion is substantially thicker than remaining portions of the plate.
摘要:
Single point optical probes for measuring three-phase characteristics of fluid flow in a hydrocarbon well and methods of processing signals generated by the probe are disclosed. A single fiber optic probe is coupled to a light source and apparatus for detecting reflectance and fluorescence. Light is delivered to the tip of the probe where it exits the probe and illuminates the liquid ambient the probe tip or is internally reflected in the probe when gas is located at the probe tip. If the fluid at the probe tip is oil, the light exits the probe, illuminates the oil, and causes the oil to fluoresce. According to one signal processing method of the invention, the reflectance signal is binarized at a threshold to provide a gas/liquid quasi-binary signal which changes over time. A time fraction of the signal values is used to calculate the gas holdup. According to other signal processing methods of the invention, the fluorescence indication signal is processed by taking its derivative (and if desired a second derivative) to determine the "corners" of the fluorescence signal over time. The derivative signal exhibits a positive and a negative peak which are separated by time. The time between the peaks is used to calculate oil holdup and the amplitude of one of the peaks is used to calculate the velocity of the oil drop.
摘要:
A borehole tool having adjacently located fluid injection/withdrawal apparatus and an electromagnetic measurement apparatus is provided. The electromagnetic measurement apparatus can be an imaging apparatus for helping set the tool in desired locations for permeability testing via fluid injection or withdrawal. In a second mode, during fluid injection or withdrawal, and if desired, before and/or after injection or withdrawal, a plurality of electromagnetic measurements (images) are made. Based on the electromagnetic and hydraulic measurements, and a model which interrelates the measurements, determinations are made as to various characteristics of the formation, including effective permeabilities. Related methods for utilizing the tool and for treating the data in an integrated fashion are also set forth.
摘要:
An apparatus, method and system are provided for characterizing fluid trapped in a subterranean formation using a downhole tool that includes an elongated body and a probe body. The probe body is moveable from and back into the elongated body. The probe body defines a flow line and supports a pressure sensor for measuring fluid pressure in the flow line, a piston and an electrical motor actuator that is adapted to move the piston in order to vary volume of the flow line. The integral electrical motor actuator, piston, pressure sensor and flow line of the probe body can provide for measurement of formation pressure and/or formation mobility.
摘要:
An apparatus, method and system are provided for characterizing fluid trapped in a subterranean formation using a downhole tool that includes an elongated body and a probe body. The probe body is moveable from and back into the elongated body. The probe body defines a flow line and supports a pressure sensor for measuring fluid pressure in the flow line, a piston and an electrical motor actuator that is adapted to move the piston in order to vary volume of the flow line. The integral electrical motor actuator, piston, pressure sensor and flow line of the probe body can provide for measurement of formation pressure and/or formation mobility.
摘要:
A method for producing, in a hydrocarbon well, a signal indicative of a local flow parameter of a multiphase fluid, includes the steps of placing at least one local sensor in the fluid and producing a signal whose level is characteristic of the phase in which the sensor is immersed, the signal being generated at a spike whose radius of curvature is less than 100 microns. The method is applicable to determining hold-ups of different phases of the fluid.
摘要:
Characteristics of invasion profiles exhibiting effects of gravity, and particularly their manifestations on resistivity logs of a plurality of different radial depths of investigation, are used to determine formation characteristics, including vertical permeability. One embodiment includes the following steps: suspending a logging tool in the borehole; producing a plurality of resistivity measurements, having respectively different radial depths of investigation, as the logging device is moved through the borehole, to obtain a plurality of resistivity logs; determining the presence of a buoyancy marker in the resistivity logs in a formation bed invaded with filtrate from the drilling mud, and the extent of the buoyancy marker; and determining permeability of the formations as a function of the extent of the buoyancy marker.
摘要:
A formation testing probe assembly comprising an elongated packer having a surface configured to be urged by the probe assembly towards a wall of a wellbore extending through the formation. The formation testing probe assembly further comprises a plate embedded in the elongated packer and including a central structural portion extending along a centerline of a substantial length of the plate, wherein the central structural portion is substantially thicker than remaining portions of the plate.
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.