Maintain high ROP, obtain quality logging data offshore Thailand

Pearl Oil operates in the Gulf of Thailand where fast drilling at rates of more than 1,000 ft/h is the standard. The company was drilling an S-shaped well at high ROP and needed to identify GOC to land the well approximately 5 ft below GOC in a highly deviated section. However, obtaining logging data with a chemical nuclear source was risky in this complex formation with poor borehole conditions. To obtain the full suite of real-time measurements that Pearl needed, Schlumberger introduced the NeoScope sourceless formation evaluation service.

Obtain petrophysical data with sourceless LWD technology

The NeoScope service—the industry’s only pulsed-neutron-generator- based (PNG) LWD technology—reduces risk by eliminating the need for chemical sources. The service also provides the complete petrophysical data needed in the shortest multifunction LWD collar available. The Orion II telemetry platform increases the flow of real-time data LWD and MWD systems to enhance decision making.

Using NeoScope service, the sourceless neutron-gamma-density (SNGD) measurement was obtained by detecting the gamma rays emitted from the formation nuclei through their interactions with neutrons generated by PNG. PNG nuclear logging data was obtained without the risks associated with traditional chemical nuclear logging sources, and spectroscopy and sigma were acquired for formation lithology and salinity.

Set liner with more data and less risk

NeoScope service provided Pearl with the data it needed while reducing the risk associated with a chemical nuclear source. More than 15 measurements were sent to surface at more than 1,000 ft/h through the Orion II downhole telemetry platform to identify GOC. The Orion II platform quickly provided the real-time data critical to determining where to set the 7-in liner in the highly deviated section.

The logging interval was from 1,200 to 5,480 ft MD, and GOC in the target sandstone was identified at approximately 5,454 ft MD. The recorded- mode data, including SNGD and spectroscopy measurements, were used for further petrophysical analysis.