Evaluate formation ahead of development well drilling
Offshore Libya, an operator sought to enhance future gas production when
drilling 13 development wells during Phase II of its FDP. A lack of image data
and core analysis meant that the field’s subsurface geology was unclear
prior to campaign commencement.
For optimal results within the FDP, the operator decided to acquire
image logs—subsurface images would enable better understanding of the
heterogonous carbonate formation. With improved visibility, the drilling team
could accurately determine formation tops, measure the maximum and minimum in
situ horizontal stresses, and identify vuggy intervals for the best perforation
zones in development wells. Such data were critical as the operator planned a
vertical well completion design.
Obtain high-resolution subsurface images for better visualization
The geoVISION service plays a critical role in illuminating subsurface
geology, clarifying structural uncertainties, and avoiding misinterpretation by
providing high-resolution images with a nearly core-like level of detail. The
service enables interpretation in memory mode or real time without interrupting
drilling operations, saving valuable rig time.
In this application, the geoVISION service was deployed with ELANPlus
analysis, the sonicVISION service, and true stratigraphic thickness points to
enable comprehensive structural and sedimentological reservoir performance
analysis. The advanced interpretation of images provided through the geoVISION
service was performed using the Techlog platform.
Identify critical reservoir characteristics to improve planning
Schlumberger experts used the geoVISION service and Techlog platform to
interpret the subsurface geological images to provide a better understanding of
carbonate facies and vuggy distributions, even in a formation with resistivity
exceeding 2,000 ohm. The interpretation also provided a detailed knowledge of
the basin’s geology for better drilling decisions throughout the FDP. With
reduced uncertainty around the characteristics of the formation, the operator
was able to design well completions that would mitigate undesired water
breakthrough in highly vuggy carbonate formations and identify the best
perforation zones.
The enhanced images from the geoVISION service enabled the operator to
confidently identify vugs, fractures, and bed boundaries. With this structural
and stress analysis was performed to identify fracture direction for use in the
drilling of planned horizontal wells.
Looking ahead, the operator used the improved correlation certainty,
confirmed lateral positions within the reservoir, and a better understanding of
reservoir properties to design a stimulation program for optimal future
development wells in the area.
