Schlumberger

Case Study: NeoScope Sourceless Neutron-Gamma Density Correlates to Conventional Density Measurement

Correlation validates PNG measurements that eliminate the need for chemical nuclear sources

Challenge: Acquire a full suite of formation evaluation measurements in two offshore wells in a field where requirements for handling chemical nuclear sources are becoming more and more stringent.

Solution: Use NeoScope sourceless formation-evaluation-while-drilling service that provides multifunction logging data without using a chemical nuclear source.

Result: Validated NeoScope pulsed neutron generator (PNG) measurements through comparison with conventional gamma-gamma-density (GGD) measurements while eliminating requirements associated with transporting, storing, and possibly abandoning a chemical nuclear source. Saved an average of 6 hours of rig time per well by eliminating source loading and unloading and by providing close-to-the-bit measurements.

Logging while drilling in complex, multilayered presalt formation

An operator drilling in the complex, multilayered presalt formation offshore Angola needed to get a complete and accurate suite of formation evaluation measurements to fully evaluate the reserves in place. To acquire the measurements the operator needed, Schlumberger introduced the NeoScope PNG-based service that provides sourceless logging-while-drilling services.

Sourceless neutron-gamma-density measurements for risk avoidance

NeoScope service is the industry’s only fully sourceless multifunction formation evaluation service that eliminates all the risks associated with a chemical source while providing a comprehensive suite of measurements in the first 16 ft of a single 25-ft collar. The NeoScope PNG-based service determines the formation density from gamma rays induced by the interaction of high-energy neutrons with the formation. Sourceless neutron-gamma density (SNGD), together with the other NeoScope measurements, allows comprehensive formation evaluation while drilling.

Complete formation evaluation data without nuclear risk

The SNGD measurements from two wells were compared with conventional GGD nuclear measurements, showing a close correlation over the logged interval. Because of this correlation, the operator will use the NeoScope service in future wells to eliminate transportation, storage, and possibly abandonment issues associated with chemical nuclear sources. On average, the operator saved 6 hours of rig time per well by eliminating source loading and unloading and by having all measurements close to the bit.


Download: NeoScope Sourceless Neutron-Gamma-Density Correlates to Conventional Density Measurement (0.79 MB PDF)

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