摘要:
A sonde and an apparatus for the deployment thereof against a well casing is described, the sonde comprising a resilient C-shaped member and at least one sensor.
摘要:
A downhole receiver for gathering seismic and sonic data from inside a borehole includes a substantially tubular housing adapted for axial connection to a tool string, and one or more sensors. A damping element is provided to flexibly couple each sensor to the tubular housing. An actuator extends the one or more sensors substantially radially with respect to the tubular housing to clamp the sensors against the wall of the borehole. In selected embodiments, the sensors may be one or multiple component geophones, accelerometers, hydrophones, vibrometers, or the like.
摘要:
Methods and apparatus for suppression of wave energy within a fluid-filled borehole using a low pressure acoustic barrier. In one embodiment, a flexible diaphragm type device is configured as an open bottomed tubular structure for disposition in a borehole to be filled with a gas to create a barrier to wave energy, including tube waves. In another embodiment, an expandable umbrella type device is used to define a chamber in which a gas is disposed. In yet another embodiment, a reverse acting bladder type device is suspended in the borehole. Due to its reverse acting properties, the bladder expands when internal pressure is reduced, and the reverse acting bladder device extends across the borehole to provide a low pressure wave energy barrier.
摘要:
An acoustic logging tool includes external baffle assemblies forming a waveguide structure at the acoustic source. The logging tool is designed for acoustic logging of earth formation surrounding a borehole. The external baffle assemblies form a waveguide structure that is designed to increase signal to noise ratio in an acoustic logging tool using dipole or other acoustic waves. In a preferred embodiment, the acoustic logging tool includes an elongated transmitter module, and a receiver sonde having a linear array of acoustic receivers. The transmitter module includes first and second cylindrical masses spaced apart along the axis by first and second spacers. The first cylindrical mass defines a first circular facing surface and a first cylindrical outer surface. The second cylindrical mass defines a second circular facing surface and a second cylindrical outer surface. A multi-pole acoustic source is fixedly mounted between the first and second circular facing surfaces, and located on the transmitter module axis between the first and second spacers. A first annular baffle assembly surrounding the first cylindrical outer surface has a first annular facing surface co-planar with the first circular facing surface. A second annular baffle assembly surrounding the second cylindrical outer surface has a second annular facing surface co-planar with the second circular facing surface. The annular baffle assemblies form an acoustic waveguide.
摘要:
An acoustic isolator for attenuating through-tool acoustic signals comprises a plurality of u-shaped link members, where each link member has two sets of ears. A plurality of yoke members are adapted to fit between cooperating sets of ears. A plurality of pins connect the plurality of u-shaped link members to the plurality of yoke members for providing limited flexural compliance. The isolator may be made from metallic and/or composite materials.
摘要:
A wellbore system and method for producing seismic waves in an earth formation. The system comprises a cavity containing fluid. The cavity is in a space between a wellbore tubular, which may be casing or production tubing, and the wellbore formation. A device is provided for generating pressure waves in the cavity at resonance frequencies of the cavity. The pressure waves generate seismic waves that radiate into the adjacent earth formation that may be recorded. The recorded seismic waves may be used to determine parameters of interest of the earth formation.
摘要:
An acoustic logging tool includes external baffle assemblies forming a waveguide structure at the acoustic source. The logging tool is designed for acoustic logging of earth formation surrounding a borehole. The external baffle assemblies form a waveguide structure that is designed to increase signal to noise ratio in an acoustic logging tool using dipole or other acoustic waves. In a preferred embodiment, the acoustic logging tool includes an elongated transmitter module, and a receiver sonde having a linear array of acoustic receivers. The transmitter module includes first and second cylindrical masses spaced apart along the axis by first and second spacers. The first cylindrical mass defines a first circular facing surface and a first cylindrical outer surface. The second cylindrical mass defines a second circular facing surface and a second cylindrical outer surface. A multi-pole acoustic source is fixedly mounted between the first and second circular facing surfaces, and located on the transmitter module axis between the first and second spacers. A first annular baffle assembly surrounding the first cylindrical outer surface has a first annular facing surface co-planar with the first circular facing surface. A second annular baffle assembly surrounding the second cylindrical outer surface has a second annular facing surface co-planar with the second circular facing surface. The annular baffle assemblies form an acoustic waveguide.
摘要:
A downhole electrical power system provides long term electrical power in a downhole environment. In a described embodiment, a downhole electrical power system includes a power source which supplies electrical power to a well tool interconnected in a tubular string. The power source includes a voltaic cell.
摘要:
A borehole seismic shuttle tool includes (a) a tool body having a cavity with an opening in the wall of the tool body; (b) an anchoring arm attached to the tool body and operable to anchor the tool body to the borehole wall; (c) a sensor package positioned in the cavity and mounted on resilient mounts which act to urge the sensor package in the direction of the opening, such that when the tool body is anchored to the borehole wall, the sensor package projects part way through the opening and is held against the borehole wall by the action of the resilient mounts. The tool is characterised in that when the tool body is not in contact with the borehole wall, peripheral portions of the sensor package is urged into contact with the tool body wall surrounding the opening.
摘要:
The invention is a method and apparatus for measuring the quality of acoustic coupling between a wellbore wall and a borehole seismic sensor system. The system includes the steps of positioning the system at a desired depth in the wellbore and activating a locking mechanism powered by a DC motor. The motor then has broadband AC applied to it to cause vibration of the system. The output of at least one seismic sensor in the system is processed in a spectrum analyzer, and the result is checked for the presence or absence of natural resonance of the system. In a particular embodiment, the system response to the broadband AC is used to generate an inverse filter operator to compensate the system response to a geophysical survey for partial acoustic coupling.