Tool - Schlumberger Ngi

Calibration followed the established Schlumberger Natural Gamma Spectrometry (NGS) protocol, using a five‑window spectroscopy method and a dedicated calibration pit in Clamart, France. Data were processed on‑site with the Schlumberger Ideal’ software package, just after raw data were downloaded from the tool.

In thinly bedded reservoirs (where layers of sand and shale alternate), conventional logging tools often average the readings together, making it difficult to pinpoint pay zones. The high vertical resolution of the NGI tool allows for precise evaluation of these thin layers. 4. Core-Log Integration

: Includes specialized versions like the NGI-X , which features advanced electronics for better signal processing and reliability in complex borehole conditions. Core Applications

The Schlumberger NGI tool is a powerful solution for where conventional resistivity methods fail. By directly measuring water-filled porosity via dielectric dispersion, it provides a robust ( S_xo ) independent of water salinity. schlumberger ngi tool

This paper explores the application of the (Next Generation Imager) tool in characterizing heterogeneous reservoir facies. Traditional imaging tools often struggle with coverage gaps in highly deviated wells or specific mud environments. The NGI platform overcomes these limitations through its innovative pad design and high-frequency transmitter system. We present a case study demonstrating how NGI data improves the identification of micro-fractures, secondary porosity, and thin-bed lamination, leading to more accurate integrated stratigraphic and structural reservoir models. 2. Introduction

The Schlumberger NGI (Near-bit Gamma Imaging) tool is a logging-while-drilling (LWD) device positioned directly behind the drill bit. Its primary function is to provide real-time, high-resolution gamma ray measurements with directional sensitivity at the bit . Unlike conventional gamma ray sensors located 10–30 meters behind the bit, the NGI tool delivers near-instantaneous lithology detection, enabling precise geosteering, early formation evaluation, and optimized well placement—especially in thin-bedded or heterogeneous reservoirs.

: Accurate imaging of the borehole helps in placing completion equipment more effectively, particularly in horizontal or highly deviated wells. The high vertical resolution of the NGI tool

While standard spectroscopy tools average these measurements over a single bulk volume around the tool, the . It segments the measurements into discrete angular bins, delivering a fully oriented, 360-degree image log of elemental concentration variations. Tool Physics and Technical Architecture

The represents a milestone in oilfield wireline logging, specifically engineered to deliver high-resolution borehole microresistivity imaging in challenging oil-based mud (OBM) environments. Developed by SLB (formerly Schlumberger), the NGI technology bypasses the historical physical limitations of traditional water-based mud imagers, providing geoscientists and reservoir engineers with photorealistic, core-like structural and stratigraphic evaluation directly from the borehole wall. The Evolution of Mud-Based Borehole Imaging

principle. It injects a high-frequency alternating current into the formation via capacitive coupling between two current electrodes. Resolution Core Applications The Schlumberger NGI tool is a

: Helps in recognizing depositional environments, such as identifying cross-bedding or thin laminations that standard logs might miss.

: The tool provides fine-scale microresistivity data that allows geologists to identify minute attributes of reservoir rock, including sedimentary features and textural analysis.

It utilizes multiple frequencies (e.g., F1 and F2) to optimize signal-to-noise ratios across varying mud and formation types.

Conventional resistivity tools often fail to detect gas in certain formations due to:

The NGI is a high-resolution, micro-resistivity borehole imaging tool developed by Schlumberger. It is primarily designed to create detailed, 360-degree electrical images of the wellbore wall.