摘要:
Automatic detection and accurate time picking of weak events embedded in strong noise such as microseismicity induced by hydraulic fracturing is accomplished by: a noise reduction step to separate out the noise and estimate its spectrum; an events detection and confidence indicator step, in which a new statistical test is applied to detect which time windows contain coherent arrivals across components and sensors in the multicomponent array and to indicate the confidence in this detection; and a time-picking step to accurately estimate the time of onset of the arrivals detected above and measure the time delay across the array using a hybrid beamforming method incorporating the use of higher order statistics. In the context of hydraulic fracturing, this could enhance the coverage and mapping of the fractures while also enabling monitoring from the treatment well itself where there is usually much higher and spatially correlated noise.
摘要:
Automatic detection and accurate time picking of weak events embedded in strong noise such as microseismicity induced by hydraulic fracturing is accomplished by: a noise reduction step to separate out the noise and estimate its spectrum; an events detection and confidence indicator step, in which a new statistical test is applied to detect which time windows contain coherent arrivals across components and sensors in the multicomponent array and to indicate the confidence in this detection; and a time-picking step to accurately estimate the time of onset of the arrivals detected above and measure the time delay across the array using a hybrid beamforming method incorporating the use of higher order statistics. In the context of hydraulic fracturing, this could enhance the coverage and mapping of the fractures while also enabling monitoring from the treatment well itself where there is usually much higher and spatially correlated noise.
摘要:
Systems, methods, and apparatus to drive reactive loads are disclosed. An example apparatus to drive a reactive load includes a reactive component in circuit with the reactive load, a first switching element in circuit with the reactive load to selectively hold the reactive load in a first energy state and to selectively allow the reactive load to change from the first energy state to a second energy state, a second switching element in circuit with the reactive load to selectively hold the reactive load in the second energy state and to selectively allow the reactive load to change from the second energy state to the first energy state, and a controller to detect a current in the reactive load, and to control the first and second switching elements to hold the reactive load in the first or the second energy state when the current traverses a threshold.
摘要:
A multimode acoustic source device for disposition in a borehole formed in a subterranean formation is aligned along an axial axis of the borehole and has a plurality of radiating plates circumferentially disposed about the axial axis. A drive mechanism is proposed to independently and reversibly move each radiating plate from a first position to a second position in a direction transverse to the axial axis. This enables the multimode source to generate each of several azimuthal modes for logging a subterranean formation.
摘要:
Systems, methods, and apparatus to drive reactive loads are disclosed. An example apparatus to drive a reactive load includes a reactive component in circuit with the reactive load, a first switching element in circuit with the reactive load to selectively hold the reactive load in a first energy state and to selectively allow the reactive load to change from the first energy state to a second energy state, a second switching element in circuit with the reactive load to selectively hold the reactive load in the second energy state and to selectively allow the reactive load to change from the second energy state to the first energy state, and a controller to detect a current in the reactive load, and to control the first and second switching elements to hold the reactive load in the first or the second energy state when the current traverses a threshold.
摘要:
A multimode acoustic source device for disposition in a borehole formed in a subterranean formation is aligned along an axial axis of the borehole and has a plurality of radiating plates circumferentially disposed about the axial axis. A drive mechanism is proposed to independently and reversibly move each radiating plate from a first position to a second position in a direction transverse to the axial axis. This enables the multimode source to generate each of several azimuthal modes for logging a subterranean formation.
摘要:
An acoustic transducer comprises two pairs of opposite elongate segments (20) placed inside a deformable tube (14). Drive means (22) operable to expand in a direction orthogonal to the axis of the tube are disposed between the segments of each pair. The drive means occupy a substantial portion of the inside volume of the tube. A preferred arrangement includes drive means for a pair of segments longitudinally displaced from the drive means for the other pair. Drive means may be constituted by stacks of piezoelectric pellets (24) extending radially relative to the axis of the tube. A pressure compensation system is provided to keep the pressure inside the tube (14) substantially equal to the external pressure. Longitudinal flutes (14a) are formed inside the tube (14) between the segments (20) to facilitate tube deformation and amplify volume variation.
摘要:
The present invention discloses an acoustic borehole source and method of using the source for generating elastic waves through an earth formation that may be used for logging or permanent installations. The acoustic source is comprised of a first motorized reaction mass and at least two pads, each pad connected to the sonde and the motorized reaction mass using pushing rods. In an alternate embodiment, the source has a first and second motorized reaction mass and at least two pads. The motorized reaction masses may be activated to allow the pads to move at an angle α relative to the axis of the sonde. In a third embodiment, the acoustic borehole source includes additional pairs of motorized reaction masses so that pads may be independently activated.
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:
The present invention discloses an acoustic borehole source and method of using the source for generating elastic waves through an earth formation that may be used for logging (such as by wireline) or permanent installations. In one embodiment, the acoustic source is comprised of a first motorized reaction mass and at least two pads, each pad connected to the sonde and the motorized reaction mass using pushing rods. To ensure proper positioning within the borehole, the sonde is anchored against the borehole wall using at least two of the pads or using a separate anchoring means. In a second embodiment, an acoustic borehole source is comprised of a first and second motorized reaction mass and at least two pads. The motorized reaction masses may be preferentially activated to allow the pads to move at an angle α relative to the axis of the sonde. In a third embodiment, the acoustic borehole source includes additional pairs of motorized reaction masses so that pads may be independently, preferentially activated.