Downhole seismic sources for Reverse 3D-VSP surveys

Naville, Charles; Ásmundsson, R.; Þórhallsson, Sverrir; Asgrimur, G.; Kollé, J.J.; Gillot, E.

doi:10.3997/2214-4609.20145278

Cited by 4 publications

(1 citation statement)

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“…Downhole sources are investigated to perform 2D and 3D while‐drilling borehole applications in the framework of oil, gas and energy resources exploration (Poletto and Miranda ; Kolle and Theimer ; Naville et al . ; Heigl et al . ).…”

Section: Introductionmentioning

confidence: 99%

Drill‐bit seismic monitoring while drilling by downhole wired‐pipe telemetry

Poletto

Miranda

Corubolo

et al. 2014

Geophysical Prospecting

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Drill‐bit seismic while drilling provides reverse vertical seismic profiles with large configurations of surface seismic sensors. This seismic while drilling technique makes it possible to predict the formation changes ahead of the bit and to image 2D and 3D structures without interfering with the drilling activity. The method is based on the recording of reference (pilot) signals which enable us to recognize and process the signal of the downhole drill‐bit source, thus obtaining impulsive seismograms after the crosscorrelation and deconvolution of the pilot signals and the seismic data recorded by surface or crosswell geophones. One issue in the application of this methodology can be the loss of the transmitted energy for the reference signal propagated from the bit to the surface through the drill string, when the pilot signals are recorded at the surface, at the top of the drill string. It is well known that with polycrystalline diamond compact bits, the pilot signal recorded at the surface may be weak and consequently the seismic while drilling results are poor. This may also happen during drilling in the sliding mode without pipe rotation, and in highly deviated or horizontal wells. A solution to improve the drill‐bit seismic while drilling method in these conditions is to record the reference signal in the proximity of the bit source, using downhole near‐bit tools to get good‐quality measurements of the pilot signal. We present drill‐bit seismic while drilling results obtained in a drilling test using wired pipes for high‐rate communication from bottom hole to the surface. The results demonstrate the applicability of this integrated approach as a standard procedure. The advantage of this is to provide real‐time synchronized reverse vertical seismic profiles, as well as high‐resolution and good‐quality data in terms of S/N and high‐frequency content. The method improves the use of the working drill bit as a downhole seismic source with different types of bit and drilling conditions.

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Section: Introductionmentioning

confidence: 99%

Drill‐bit seismic monitoring while drilling by downhole wired‐pipe telemetry

Poletto

Miranda

Corubolo

et al. 2014

Geophysical Prospecting

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2021

Drilling Engineering

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Seismic-while-drilling drill-bit source by ground force: Concept and application

et al. 2020

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For four decades, the use of the drill-bit seismic source has been evaluated extensively and investigated for seismic-while-drilling (SWD) purposes. After an initial diffusion phase, however, the routine application on drill-bit reverse vertical seismic profiling (RVSP) has declined because of issues related to variability in the signal-to-noise ratio of drill-bit signals obtained with different drilling conditions. Consequently, additional efforts have been dedicated to improving the recording of reference signals. Recent technology developments enable direct ground-force pilot measurements at downhole positions close to the bit, which enable reliable estimations of the far-field drill-bit-radiated signature. The knowledge of the ground force below the source in the near-field is a key aspect not only for the exploitation of the drill-bit source but also for conventional seismic vibrator sources. The SWD deconvolved results obtained by the ground force are different from those obtained by recording only motion vibration, such as acceleration. The ground force and particle velocity are linked by a complex impedance in the near-field, and together they provide dual measurements. In addition, the ground force provides signals with effective coupling conditions at the bit-rock interface in the presence of the drill-bit displacement action with penetration during rock fracturation. The analysis of the impedance at the bit source includes the drillstring reflections, which are observed in the reference drillstring pilot signal and are simulated by using an appropriate mechanical model. The processing of real seismic signals with different approaches by deconvolution and correlation using ground-force and motion signals produces improvements in the extraction of the source signal, with effective removal of the undesired pilot wavefields, and with cleaner estimations of the drill-bit seismic wavefields in a crosswell survey.

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Downhole seismic sources for Reverse 3D-VSP surveys

Cited by 4 publications

References 0 publications

Drill‐bit seismic monitoring while drilling by downhole wired‐pipe telemetry

Drill‐bit seismic monitoring while drilling by downhole wired‐pipe telemetry

References

Seismic-while-drilling drill-bit source by ground force: Concept and application

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