Challenge: Maximize wellbore intersection with natural fractures to optimize oil recovery from highly faulted zone in Niobrara shale.
Solution: Use real-time images from MicroScope resistivity imaging-while-drilling service to confirm borehole position relative to target formation and identify and characterize natural fractures.
Result: Successfully placed horizontal lateral within predefined target interval and completed well for production.
An independent operator in the western US planned to drill a horizontal lateral to produce oil
from a complex reservoir in the Niobrara shale formation. Prior to drilling the lateral, a complete
openhole log, including images from an FMI fullbore formation microimager, was acquired
in a vertical well to identify the best horizontal target interval, confirm the presence of natural
fractures, and determine the maximum horizontal stress orientation.
This information was used to select the direction the horizontal lateral should be drilled to
maximize the number of natural fractures it would intersect and facilitate the development
of a complex fracture network during stimulation. To enhance reservoir understanding and
optimize oil recovery, the operator needed to correlate and confirm the position of the borehole
relative to the target formation while drilling.
MicroScope service provided high-resolution electrical borehole images, azimuthal gamma ray
measurements, and multidepth formation resistivity measurements in real time. This information,
together with mud gas data, was used to constantly update the structural model and determine
wellbore trajectory relative to the target interval in the highly faulted reservoir.
When the lateral had been drilled to about three-quarters of its planned length, it crossed
a major fault plane with a significant fault throw, which placed the lateral below the target
formation within just a few hundred feet of TD. To improve reservoir exposure, the operator
decided to drill a sidetrack from the existing lateral.
The improved structural understanding that interpretation of the real-time MicroScope images
provided made steering the sidetrack less demanding than steering the original lateral. While
drilling the sidetrack, real-time MicroScope images revealed that there was less structural
change than there had been in the first half of the lateral. Constant updating of the structural
model based on real-time data enabled successful placement within the predefined target
interval and well completion.
Download: MicroScope Resistivity and Imaging Enable Successful Completion in Complex Shale Formation (2.10 MB PDF)