Schlumberger

Case Study: LWD Data Acquisition Saves City Oriente Limited USD 110,000

EcoScope service provides measurements needed for reservoir evaluation—without difficult openhole logging run

Challenge: Acquire reservoir evaluation data in difficult-to-log deviated well in sedimentary basin in Ecuador.

Solution: Use EcoScope multifunction LWD service to acquire data and EcoView interpretation system to estimate porosity, fluid saturation, and permeability.

Result: Saved an estimated 2 days of rig time and USD 110,000 by eliminating need for difficult openhole logging run. Provided petrophysical answers required to optimize field development.

Productive drilling challenging

Data acquisition made productive drilling a challenge in a deviated well being drilled by City Oriente Limited in a Sub-Andean sedimentary basin in Ecuador. Borehole instability and a high risk of sticking, due to diverse depositional environments and tectonic stresses, made conventional openhole logging difficult. As a result, data acquisition in offset wells logged conventionally had been time-consuming, costly, and often incomplete.

Unique real-time measurements evaluate reservoir

The EcoScope multifunction LWD service enabled City Oriente to meet the challenge and efficiently acquire the needed reservoir evaluation data—in real time for more productive drilling. Even washed-out intervals in a transition zone—which, typically, cause difficulties in drilling and openhole logging—were successfully identified and evaluated using EcoScope calipers and images.

Hydrocarbon saturation in the main reservoir target was determined using the EcoScope service’s unique volumetric formation capture cross section—sigma—measurement. Another unique EcoScope measurement—elemental capture spectroscopy—provided an independent lithology indicator that was used to derive matrix-corrected density and porosity. Permeability was estimated from the EcoScope measurements using the EcoView system.

Save rig time and cost

Using the EcoScope LWD service rather than conventional openhole logging saved City Oriente an estimated 2 days of rig time and USD 110,000—and provided the petrophysical answers needed to optimize field development. The real-time EcoScope measurements reduced interpretational uncertainties, permitting confirmation of hydrocarbon zones, and helped define the zones’ productive potential by allowing estimation of permeability with the EcoView system. Acquiring measurements in real time also aided decision-making and avoided the difficulties inherent with openhole logging in an unstable borehole.


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