This paper discusses design and implementation of a new-generation nuclear magnetic resonance (NMR) wireline logging tool. The tool is a multifrequency, eccentered gradient-field design with multiple depths of investigation (DOI) spanning a range of several inches. The broad range of DOIs enables radial profiling of saturation distribution and formation damage. Because of the eccentered mode of operation and sensor design, the DOIs are maintained regardless of hole size and temperature. The DOIs range from 1 to 4 in. The tool features multiple sensors, including a large antenna for fluid characterization and complementary small-aperture antennae for high-resolution acquisition modes. The sensors can be operated either separately or simultaneously at logging speeds of up to 3,000 ft/hr. Comparison of the responses is used to provide high-resolution identification of long T1 fluids such as light hydrocarbons. New NMR acquisition sequences such as Diffusion Editing (DE*) are readily implemented on the new tool, which has a highly flexible pulse programmer. Combining the new acquisition methods with the multifrequency capability of the tool and Magnetic Resonance Fluid (MRF*) characterization processing provides robust fluid saturation and oil viscosity answers.
A Next-Generation Wireline NMR Logging Tool
2003
7 Seiten, 13 Quellen
Conference paper
English
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