Orientation and calibration of acoustic vector sensor arrays
AssigneeHalliburton Energy Services, Inc.
InventorsTacio Jose de Oliveira da Silva, Bruce E. Cornish
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Abstract
The specification describes a system and related method for determining the orientation of acoustic vector sensors installed in well bores that utilizes acoustic signals of known orientation in the casing to determine the orientation of the acoustic vector sensors. The acoustic vector sensors may be part of a string of acoustic sensors for acoustic or seismic surveys of subsurface formations, or may also be coupled to downhole devices for which orientations need to be know.
Claims36
In a system having a plurality of acoustic vector sensor pods located in a cased borehole, a method of determining an orientation of the acoustic vector sensor pods comprising:
- inducing in the casing an acoustic signal of known orientations;
- detecting the acoustic signal by the plurality of acoustic vector sensor pods;
- and
- determining the orientation of each of the acoustic vector sensor pods in relation to the acoustic signal of known orientation.
A structure comprising:
- a well bore having a casing;
- a plurality of vector sensing devices coupled to an electrical cable forming a sensor string, the sensor string within the casing and each vector sensing device contacting the casing;
- a transmitting device having a known orientation within the casing, the transmitting device imparts acoustic energy into the casing;
- a surface computer coupled to each of the plurality of sensing devices and the transmitting device;
- and
- wherein the surface computer is adapted to activate the transmitting device, read signals created by the vector sensing devices responsive to acoustic energy in the casing, and calculate an orientation of the vector sensing devices relative to the transmitting device.
In a system having a plurality of vector sensors disposed within a well bore having a casing, a method of determining the orientation of the plurality of vector sensors comprising:
- creating a shear wave in the casing;
- establishing orientations of the vector sensors relative to the shear wave;
- and
- calculating an orientation of the plurality of vector sensors based on one of:
- knowing an orientation of one of the plurality of vector sensors;
- and knowing an orientation of the shear wave.
A method comprising:
- installing a plurality of acoustic sensing devices in a well bore having a casing;
- establishing a baseline responsiveness of the acoustic sensing devices to acoustic signals in the casing;
- and thereafter
- testing the plurality of acoustic sensing devices to determine a deviation of their responsiveness from the baseline responsiveness.
A method of making four-dimensional seismic surveys, the method comprising:
- installing a plurality of seismic vector sensors in a cased borehole;
- determining an orientation of the plurality of seismic vector sensors;
- determining a first sensitivity of the plurality of seismic vector sensors;
- performing a first three-dimensional seismic survey;
- and thereafter
- determining a second sensitivity of the plurality of seismic vector sensors;
- performing a second three-dimensional seismic survey;
- correcting data of the second three-dimensional seismic survey based on the difference between the first and second sensitivity;
- and
- combining the first and second three-dimensional seismic survey to create the four-dimensional seismic survey.
A method a determining an orientation of an acoustic vector sensor pod installed in a cased borehole, the method comprising:
- creating an acoustic signal in the casing having a known orientation;
- detecting the acoustic signal with the acoustic vector sensor pod;
- and
- calculating the orientation of the acoustic vector sensor pod based on the acoustic signal having a known orientation.
Dependencies are inferred from the claim text.