The NGI tool provides a direct measurement of gas saturation independent of water resistivity ((R_w)) by exploiting the of reservoir rocks.
The Schlumberger NGI (New Generation Imager) is a high-resolution wireline borehole imaging tool specifically designed for oil-based mud (OBM) environments. SCIRP Open Access schlumberger ngi tool
| Feature | Detail | |---------|--------| | | Integrated into the bottom hole assembly (BHA), typically 1–2 m behind the bit | | Sensors | Multiple azimuthally oriented scintillation detectors (usually 2 to 16 sectors) | | Measurement | Natural gamma ray API (total count rate) | | Azimuthal Coverage | 360° around the tool | | Data Transmission | Real-time via mud pulse telemetry (compensated for limited bandwidth) and high-resolution memory recording | | Temperature Rating | Up to 150°C (302°F) | | Pressure Rating | Up to 25,000 psi (172 MPa) | | Rotation Speed | Optimal from 60–200 RPM | The NGI tool provides a direct measurement of
