A method and device for determining reservoir irreducible water saturation

Abstract

The present invention provides a reservoir irreducible water saturation determining method and device. The method includes the following steps that: an exponential hyperbolic sine function is constructed, and Laplace transformation is performed on the exponential hyperbolic sine function, so that a progressive step function can be obtained; an unknown parameter in the exponential hyperbolic sine function is solved according to a special value condition which the progressive step function satisfies, and the constructed exponential hyperbolic sine function is updated according to the solved unknown parameter; integral transformation is performed on acquired nuclear magnetic resonance echo data according to the updated exponential hyperbolic sine function, and reservoir irreducible water saturation can be determined. According to the method and device provided by the invention, inverse Laplace transformation for inversion is not required to be performed on the nuclear magnetic resonance echo data, uncertainties caused by the inversion can be avoided; and accurate irreducible water saturation can be obtained under a condition that the signal noise ratio of the nuclear magnetic resonance echo data is low.

Description

technical field [0001] The invention relates to the technical field of well logging data processing in petroleum exploration, in particular to a method and device for determining the irreducible water saturation of a reservoir. Background technique [0002] NMR logging is currently the only logging method that can distinguish mobile fluid from bound fluid in the formation, and has unique advantages that other logging methods do not have. Whether the calculation of reservoir irreducible water saturation is accurate or not directly affects the accuracy of reservoir oil and gas evaluation, the rationality of reserve calculation and the reliability of productivity prediction, and it also directly affects the later test and completion plan. Therefore, it is of great significance to study an accurate determination method of irreducible water saturation in reservoirs. [0003] At present, the method of determining the irreducible water saturation by NMR logging is mainly to carry ...

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Problems solved by technology

[0004] This application provides a method and device for determining the irreducible water saturation of a reservoir, which is used to solve the problem of obtaining T by inverting the NMR echo data in the prior art. 2 spectrum, using T 2 The method of obtaining the irreducible water saturation by the cut-off value has an inaccurate inversion result, and the T obtained by the inversion 2 There is a large uncertainty in the spectrum, which leads to a large error in the calculated irreducible water saturation of the reservoir

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