Tool - Schlumberger Ngi
(when combined with density/neutron)
Multi-frequency deep dispersion filtering; isolates true rock matrix from mud cake.
| Specification | Details | |---------------|---------| | | 4¾ in, 6¾ in (and other sizes) | | Position | Directly behind the drill bit (shortest sensor offset in the industry) | | Gamma Ray Detectors | Multiple azimuthally‑spaced scintillation detectors | | Measurements | Total gamma ray (gAPI) + Azimuthal gamma ray image + Spectral K‑U‑Th (when calibrated) | | Inclination | Dynamic, high‑frequency (helps correct for tool rotation) | | Max. Temperature | 150°C (302°F) | | Max. Pressure | 20,000 psi | | Data Transmission | Real‑time mud‑pulse telemetry + memory for high‑resolution playback | schlumberger ngi tool
Understanding the Schlumberger NGI Tool: Next-Generation Borehole Imaging and Formation Evaluation
The Schlumberger NGI tool is a logging-while-drilling (LWD) tool designed to provide detailed information about the subsurface geology and geochemistry of a wellbore. This advanced tool combines nuclear and geochemical measurements to deliver high-resolution images of the formation, enabling drillers to make informed decisions about well placement, trajectory, and completion. Pressure | 20,000 psi | | Data Transmission
: Newer services like the Quanta Geo Photorealistic Imager offer even higher borehole coverage (up to 98% in 8-inch holes) and allow for faster logging speeds up to 3,600 ft/h.
The SLB NGI tool string introduces specialized, high-frequency acquisition electronics to capture microresistivity data through non-conductive and oil-based mud (OBM) systems. real‑time geosteering and formation‑evaluation tool.
The NGI operates on the principle of . Water, oil, and gas have distinct relative permittivities (dielectric constants) at high frequencies:
While the original NGI is obsolete, natural gamma ray imaging is now a standard, high‑technology service. Schlumberger (now ) and its subsidiary PathFinder have transformed the concept into a robust, real‑time geosteering and formation‑evaluation tool.