Отправлено: 10.06.11 06:06. Заголовок: EAGE Vienn//NMR Application with Sphere-cylinder Model for Petrophysical Evaluation

NMR Application with Sphere-cylinder Model for Petrophysical Evaluation

J. Yan* (Royal Holloway University of London) & T.Y. Liu (Tongji University)
SUMMARY
Conventional loggings provide the essential data with traditional methods for petrophysical evaluation in
reservoir characterization. However, if complex pore structure, multiple fluid systems, serious mud
invasion and various water salinities etc. existed in reservoirs, the conventional logging may fail to provide
quality data which will be probably affect the results for formation evaluation.
NMR (Nuclear Magnetic Resonance) log gives continuous, reproducible measurements with excellent
vertical high resolution. It is a powerful tool for identifying tight inter-bed in complex formation
evaluation when fluid invasion zones or/and complex fluid system exists in reservoirs.
In order to achieve the solutions for such complex formation evaluation in the gas fields of Southwest
China, we utilized both conventional logs and NMR tool to perform petrophysical evaluation, and then,
the reservoir parameters and the pore structure may be analyzed based on petrophysics.
The pore structure (also pore size distributions) in NMR analysis is key problems for reservoir evaluation;
the approach of sphere-cylinder model in oil-water porous media can be regarded as the superposition
relaxation for both spherical pore and cylindrical pore.