Source SPE/IADC-194164-MS 

MANAGING DRILLING LOSSES IN THE PERMIAN USING AIRBORNE GRAVITY FULL TENSOR GRADIOMETRY

Authors : Adam Sallee, Hans Dick, Vasudhaven - Schlumberger Western Geco, Alan Morgan, Scott Payton - Bell Geospace, David Paddock - Schlumberger

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Drilling into caves negatively affected operations by reducing the drilled footage per day and increasing costs. Improving surface well placement became possible following the mapping of hazards using Full Tensor Gradiometry (FTG) data.

Summary

This was the first application of FTG to classify drilling risk of karst features in the Permian Basin. The FTG hazard map improves operational integrity of surface location selection and is a complement to surface topography and geology considerations. The FTG data and analysis was shown to also hold promise for fault mapping and for water drilling efforts.

Key Takeaways

  • A stage tool is an inefficient tool to lift cement through caves when placed near or below a loss zone and cement plugs offer a better solution to fill up caves although there are significant risk considerations
  • The best solution is to see the risk before building the pad. This is possible via interpreted FTG data to map shallow hazards and cave systems 
  • FTG data with interpretation is superior to legacy techniques and anecdotal evidence