Seismic measurements while drilling
AssigneeBaker Hughes Incorporated
InventorsRadu Coman, Michael Neubert, Holger Mathiszik, Michael Koppe
Life of this patent
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Abstract
A downhole tool starts recording seismic energy. During the recording time, a surface seismic source is activated a specified number of times with a nominally defined separation between successive. The downhole sensor receives seismic waves resulting from the activation, but the time of the shooting sequence is not known downhole. The recorded data stream is processed and converted in real-time into seismic traces. A predefined number of traces are stacked and the quality of this sliding stack is used to detect time of the shooting sequence. The method could be used to detect one or several shooting sequences during a measurement window.
Claims20
A method of producing a seismic trace during drilling operations using a data stream generated by a sensor on a bottomhole assembly (BHA) in a borehole in an earth formation, the method comprising:
- producing the seismic trace by performing a sliding stack on a plurality of traces corresponding to a plurality of seismic signals to generate a plurality of stacked traces, with each trace of the plurality of traces based on a corresponding seismic signal of the plurality of seismic signals, and each corresponding seismic signal comprises a different corresponding interval of data from the data stream, wherein each corresponding interval of data relates to a different corresponding activation of a seismic source, the plurality of seismic signals being based on a sequence of seismic pulses having a predefined interval between successive seismic pulses.
A system for evaluating an earth formation during drilling operations, the system comprising:
- a bottomhole assembly (BHA) configured to be conveyed into a borehole for performing drilling operations;
- a seismic source at a surface location configured to be activated with a predefined sequence including a specified interval between successive activations;
- a sensor on the BHA configured to generate a data stream including a plurality of seismic signals, wherein each seismic signal comprises a different corresponding interval of data from the data stream, and wherein each signal is generated over a time interval that includes the activation of the seismic source;
- and
- a processor configured to:
- (i) perform a sliding stack on a plurality of traces corresponding to the plurality of seismic signals to generate a plurality of stacked traces, with each trace of the plurality of traces based on a corresponding seismic signal of the plurality of seismic signals, with each trace of the plurality of traces based on a corresponding seismic signal;
- and
- (ii) produce a seismic trace using the sliding stack.
A non-transitory computer-readable medium product having stored thereon instructions that when read by at least one processor cause the at least one processor to perform a method of producing a seismic trace during drilling operations using a data stream generated by a sensor on a bottomhole assembly (BHA) in a borehole in an earth formation, the method comprising:
- producing the seismic trace by performing a sliding stack on a plurality of traces corresponding to a plurality of seismic signals to generate a plurality of stacked traces, with each trace of the plurality of traces based on a corresponding seismic signal of the plurality of seismic signals, and each corresponding seismic signal comprises a different corresponding interval of data from the data stream, wherein each corresponding interval of data relates to a different corresponding activation of a seismic source, the plurality of seismic signals being based on a sequence of seismic pulses having a predefined interval between successive seismic pulses.
Dependencies are inferred from the claim text.