Industry-first continuous resistivity look-ahead-while-drilling service

Source: press release, 6 May 2019

The IriSphere service multifrequency transmitters and multireceiver BHA provide continuous resistivity that detects formation features far ahead of the drill bit
The IriSphere service multifrequency transmitters and multireceiver BHA provide continuous resistivity that detects formation features far ahead of the drill bit (illustration: Schlumberger)

Schlumberger has introduced the IriSphere* look-ahead-while-drilling service at the Offshore Technology Conference. The new service provides the industry’s first application of electromagnetic (EM) technology for detecting formation features ahead of the drill bit in oil and gas wells.

The service uses EM-based resistivity measurements more than 30 metres ahead of the drill bit, which are then compared to a prepared model that incorporates offset and other data to reveal a true downrange representation of the formation while drilling. This enables operators to make proactive decisions rather than reacting to measurements at or behind the bit while drilling wells.

“IriSphere service was created in response to the needs of our customers for risk reduction, improved drilling efficiency and optimal casing point selection,” says Tarek Rizk, president, Drilling & Measurements, Schlumberger. “Knowing what conditions lie ahead of the bit while drilling enables operators to reduce uncertainties and minimise costs by identifying geological features and deciding which actions to take before encountering them.”

More than 25 field trials were conducted with the IriSphere service in Asia, Australia, Latin America and Europe. These trials included successfully detecting reservoirs and salt boundaries, identifying thin layers, and avoiding drilling hazards, such as high-pressure formations that can lead to wellbore stability issues.

Offshore Western Australia, one customer used the IriSphere service in an unexplored part of a field to detect the reservoir 19 metres ahead of the bit while drilling and determine reservoir thickness to be 25 metres. This avoided the need to drill a pilot hole, and subsequent coring operations were optimised based on data acquired while looking ahead of the drill bit.

*Mark of Schlumberger