Decomposing and synthetic method of quasi-saturated water nuclear magnetic resonance spin echo signals

Abstract

The invention provides a decomposing and synthetic method of quasi-saturated water nuclear magnetic resonance spin echo signals. According to known saturation data and corresponding relaxation signals, influence coefficients of different oil sample saturation on the relaxation process are fixed in an optimizing and fitting mode. In terms of the relaxation signals with different oil saturation, salt water of the same size replaces oil samples, the influence coefficients are led in so as to represent influences of the oil samples with different oil saturation on the relaxation signals, and accordingly quasi-saturated water nuclear magnetic resonance relaxation signals under different oil saturation are written. Spin echo relaxation signals of a quasi-saturated water rock core are inverted, influences of different fluid types and different saturation can be removed in a certain degree, and the identification capacity of the nuclear magnetic resonance signals for a rock pore structure and fluids can be improved. According to the method, synthesis and decomposing of the quasi-saturated water rock core nuclear magnetic resonance spin echo signals are achieved, and accuracy and reliability of nuclear magnetic resonance data for assessment of the rock pore structure and fluid identification are improved.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploration and is applied to the identification of pore fluids in formation rocks and the analysis of pore structures. technical background [0002] The NMR spin echo signal is the basic data of the NMR relaxation spectrum inversion, and the NMR relaxation spectrum can be used to identify the pore fluid of formation rocks and analyze the pore structure. In practical applications, the effects of formation pore fluid and pore structure on spin echo signals are superimposed on each other. Therefore, the relaxation spectrum distribution obtained by direct inversion of spin echo signals actually includes the mutual superposition of rock pore fluid and pore structure. information, leading to difficulties in pore fluid identification and pore structure analysis with relaxation spectrum data. [0003] The existing spin echo signal inversion methods indiscriminately invert the total echo signal includi...

AI Technical Summary

Problems solved by technology

Although the accuracy and stability of the relaxation spectrum distribution can be improved by improving the inversion algorithm, it is impossible to fundamentally improve the identification of pore fluid and the analysis of pore structure because the separation and inversion of pore fluid information and pore structure information have not been realized. the accuracy of

Images