Method and device for determining oil gas saturability

Abstract

The invention provides a method and device for determining oil gas saturability. The method comprises the following steps of obtaining a long-echo distance measurement echo string and a short-echo distance measurement echo string; determining a stratum water dispersion coefficient according to actual stratum information at set experiment temperature under set experiment pressure; calculating water dispersion relaxation time according to the stratum water dispersion coefficient; and adding the water dispersion relaxation time under a long-echo distance and the water dispersion relaxation time under a short-echo distance to a short-echo distance spectrum T2, calculating and constructing an echo string, determining the property of fluid in a reservoir stratum according to the long-echo distance measurement echo string and the constructed echo string, and calculating the oil gas saturability of the reservoir stratum. According to the method and the device, the problem that extremely rich regional experience is needed for a conventional nuclear magnetic resonance shifted spectrum method is solved; the use range of a nuclear magnetic resonance well measurement fluid identification method is expanded.

Description

technical field [0001] The invention relates to the technical field of petroleum logging, in particular to a method and device for determining oil-gas saturation. Background technique [0002] In the field of petroleum exploration and well logging technology, nuclear magnetic resonance is an important reservoir fluid identification method, especially when there are "low-resistivity" oil layers with high irreducible water content, it is difficult to accurately obtain reservoir fluid identification methods with conventional resistivity fluid. Fluid information, NMR fluid identification technology is not affected by bound water, etc., can accurately identify fluids, and has a good application prospect. However, the distribution of the lateral relaxation time T2 of NMR logging will be affected by the fluid properties and pore structure. The NMR T2 of oil and water in the reservoir overlaps to a certain extent, which increases the difficulty of identifying the properties of oil a...

AI Technical Summary

Problems solved by technology

Due to the complex pore structure, it is often encountered that the short waiting time cannot fully polarize the water signal in the pore. At this time, the phenomenon of difference spectrum signals in the water layer will appear, which will lead to misinterpretation of the oil layer by the water layer and reduce the coincidence rate of NMR logging.

[0005] 2) For the spectral shift method, it mainly relies on experience, which is still quite far-fetched in theory, and it is difficult to realize the quantitative identification of oil, gas and water in practical applications

Images