July Technical Talk

When:  Jul 23, 2024 from 06:00 PM to 08:30 PM (ICT)
Associated with  Vietnam Section


Speaker: Nguyen Phuoc An, SLB

Ensuring precise positioning and orientation of a well is a crucial task prior to entering the horizontal section and optimizing reservoir exposure. Various drilling practices can be employed for this purpose, including leveraging seismic data, utilizing real-time shallow logging while drilling measurements to correlate with offset markers, and drilling pilot holes to assess geological structure. Despite the advantages and disadvantages associated with each method, they still entail considerable uncertainty due to reservoir complexity.

Recently, the development of ultra-deep directional resistivity technology has significantly advanced the field. This technology allows for detection depths of up to 250 feet which is based on resistivity contrast, enabling real-time mapping of reservoirs. With this capability, multiple resistivity layers corresponding to different geological structures can be identified before physically encountering them, obviating the need for pilot holes. Consequently, the paradigm of the landing process is transitioning from a reactive approach to a strategic one.


Common challenges in landing a well:

  • By seismic data: high uncertainty due to limited resolution
  • By real time shallow logging while drilling data: relying on reservoir continuity assumption, markers’ quality, and interpreters’ experience.
  • By drilling pilot hole: incurring extra cost, relying on reservoir continuity assumption, unwanted entering dangerous zones.

Methods, Procedures, Process:

Ultra deep directional resistivity service introduction:

  • Electromagnetic principle that depth of detection increases with transmitter vs receiver spacings with broad frequency range.
  • Providing capability of directionally detecting and remotely mapping multiple strata formation structures
  • Proactive decision making to change well trajectory in real time 
  • Game changing approach to well landing with better resolution than seismic data
  • Output with boundary, layer thickness, dip, anisotropy.

The implementation of ultra-deep directional resistivity services extends the depth of detection capabilities up to 250 feet, subject to variations based on resistivity contrast within the formation. This technology facilitates landing strategies by detecting and remotely mapping reservoir markers, thereby enabling real-time trajectory adjustments. Two case studies have been conducted to validate the efficacy of this service in achieving successful landings without the need for pilot holes. These studies serve to demonstrate the capability of the ultra-deep directional resistivity technology in effectively guiding well trajectories to desired positions with enhanced precision and efficiency.

Results, Observations, Conclusions: 

Unlocking geosteering and reservoir mapping strategy during the landing phase is now within achievable, promising to minimize geological uncertainties and enhance reservoir comprehension—all without the need for drilling pilot holes. This innovative approach not only eliminates the need for costly pilot hole drilling but also contributes to reducing CO2 emissions, aligning with sustainability goals. By expediting the transition to the production phase, this solution accelerates time-to-market, optimizing operational efficiency and maximizing profitability.


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