Borehole Seismic Solutions

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Delivering Unmatched Quality

GT through partnerships, is an industry leader in providing Wellbore Seismic Services. Many experts have indicated that Borehole related seismic data applications are underutilized in the upstream oil and gas exploration industry. Unmatched quality and quantity of recording equipment, superior processing techniques and pre-survey modeling combine to make GT borehole services unparalleled in Europe and beyond:

  • 104 levels of 3-component geophone modules, magnetic or spring bar clamping,
  • 4000+ meters of fiber optic, truck mounted cable for high capacity borehole deployment,
  • Robust and redundant recording and testing hardware and software,
  • Unique processing techniques that allow the use of surface seismic processing tools for well-bore imaging applications,
  • Model driven micro-seismic processing that differs from standard earthquake location methods, where matched P-wave and S-wave events are required. Events are located with just P-wave or just S-wave, allowing the identification of many more seismic events than traditional methods.
  • Easy Mobilization from Poland to anywhere in Europe and beyond.

There are many advantages for using borehole recorded seismic over surface recorded seismic:

  • One-way travel time, improving transmission loss and significantly improving temporal resolution and signal to noise ratio,
  • Steep-dip imaging is made possible and practical with vertical borehole arrays,
  • Long vertical arrays, allow for full wave recording with excellent depth and XY resolution.

GT’s Borehole Seismic Solutions include the following Applications:

  • Zero Offset, 2D (Walkaway) and 3D VSPs,
  • Micro-Seismic Monitoring of Fracture Stimulation,
  • VSP (Walkaway) during drilling to accurately update the target location.

 

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Our long array dramatically reduces the field acquisition time and provides better continuity records with a single source, without splicing. The results are higher quality, by definition. Unique processing techniques allow borehole imaging records to be processed by all the surface seismic processing tools available in the time domain including migration.

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Our long arrays placed in deep monitor wells, or shallow purposely-drilled monitor wells, allow for the recording and better identification of more events than standard services. Traditional methods only measure a small portion of the incident wavefield, resulting in mislocation of the loci of the event. Our processing techniques require only the identification of a P-wave or S-wave, but not both. Competitor methods require the identification of a match pare of both P-wave and S-wave to locate an event. Small magnitude events may generate only a very low amplitude S-wave, for example. As you can see, the GT partnership technique allow for the ability to detect and accurately locate significantly more micro-seismic events than the competitors methods.

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When surface seismic is missing or of low quality, a very accurate structural and stratigraphic interpretation can be created by using the upper portion of a partially drilled well to place a geophone array for use in conducting a walkaway VSP. The results of this VSP can be then used to more accurately reinterpret the structure to allow the drilling plan to be redirected. This is particularly useful in drilling horizontal wells to accurately find the “landing zone” and to avoid structural faults unseen by surface seismic.