The plan for the second well was to steer the horizontal production
section to access reserves on both sides of a secondary fault. Proceeding from
the landing point, the planned horizontal well path would first traverse the
reservoir in the lower fault block and then cross a normal fault into the upper
fault block, where the reservoir was expected to narrow.
Optimize wellbore positioning with real-time data
In the first well, the GeoSphere service mapped the top of the reservoir
in the first fault block, revealing the reservoir top 46 ft [14 m] TVD lower
than initially expected. A dip in the top reservoir structure not inferred from
seismic data was also detected. Further interpretation showed a fault in this
area. After exiting the first lobe in the shale zone, the trajectory was
adjusted downward to find the second reservoir lobe. Upon approaching the
second reservoir lobe, the top of the reservoir was detected from about 30 ft
[10 m] TVD below the wellbore.
Upon exiting the casing shoe in the second well, the inversion mapped
the reservoir top about 13 ft [4 m] above the wellbore while simultaneously
mapping the base of the reservoir along the horizontal section. The wellbore
crossed a fault, and the deep electromagnetic inversion showed good delineation
of the reservoir, correlating to what was expected from the initial model of
the lower fault block. In the upper fault block, the GeoSphere service revealed
unexpected geometry and previously unknown stratigraphic events.
The GeoSphere reservoir mapping-while-drilling service guided steering
in these two wells and several additional wells in the campaign. This enabled
Shell to optimize reservoir exposure and avoid unplanned exits from the target
reservoirs, despite depth discrepancies in reservoir models. Additionally, the
service provided information for refining geological and structural models and
for optimizing production management and ROI.