Single well system for mapping sources of acoustic energy
AssigneeExxon Production Research Company
InventorsJeffrey R. Bailey, Marion M. Ringo
Life of this patent
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Abstract
Apparatus and method for determining the location of the source of seismic energy around a well are provided. Multiple seismic receivers, each receiver having orthogonal seismic sensors, are axially spaced on a tool which is capable of sending real-time seismic signals to the surface over conventional wireline. A method for calculating the location with respect to the receivers is also provided, the method employing data from all the sensors and a performance function to minimize error in the determination of location, and a simplified method is provided for determining if a fracture has extended past a selected depth in a formation.
Claims17
Apparatus for locating a source of acoustic waves in the earth, comprising:
- an elongated body having an axis and a plurality of segments and being adapted to be connected to a wireline to allow placing the apparatus in a well;
- a plurality of receivers comprising separate segments of the body, each receiver having a radius and including retractable means for exerting a force for clamping the receiver in the well and having three orthogonal seismic sensors, each sensor producing an electrical signal responsive to an acoustic wave impinging thereon;
- and
- electronic means including a plurality of voltage controlled oscillators, each oscillator having a selected mid-range frequency, the electronic means being disposed in a segment of the elongated body and being capable of converting the electrical signal from each seismic sensor to a frequency modulated signal.
A method for determining the location of a source of seismic energy in the earth, comprising:
- placing apparatus in a well on an electric wireline, the apparatus including (a) a plurality of seismic receivers, each receiver having three orthogonal seismic sensors and (b) electronic means for converting the signal from each seismic sensor to a frequency modulated electrical signal for transmission through the wireline, the electronic means including a plurality of voltage controlled oscillators, each oscillator having a selected mid-range frequency;
- activating means for clamping the receivers in the well;
- connecting the wireline at the surface to means for converting the frequency modulated signals received from the wireline to amplitude modulated signals;
- and
- using the amplitude modulated signals at the surface to calculate the location of the source from which the seismic signal originated.
Dependencies are inferred from the claim text.