Oil and water layer recognition method suitable for volcanic reservoir

Abstract

The invention discloses an oil and water layer recognition method suitable for a volcanic reservoir. The oil and water layer recognition method comprises the following steps of performing inversion processing on an echo string by using nuclear magnetic logging data in a dual waiting time mode to obtain a long waiting time T2 spectrum and a short waiting time T2 spectrum; then performing differential spectrum processing to obtain a difference spectrum reflecting oil and gas information; performing integral processing on the difference spectrum to obtain difference spectrum porosity (Diff_Por); determining sensibility of various hydrocarbon components on an oil and water layer by gas logging data establishing a hydrocarbon characteristic ratio (Ratio_C); establishing a cross plot of the difference spectrum porosity and the hydrocarbon characteristic ratio according to existing oil testing data and determining a distinguishing boundary of the oil and water layer; extracting the difference spectrum porosity and the hydrocarbon characteristic ratio of a stratum of which oil and water are about to be recognized according to the previous steps; and effectively recognizing the oil and water layer by using the established cross plot. On the basis of nuclear magnetic differential spectrum processing, processing is carried out further to obtain the difference spectrum porosity, the cross plot is established by the difference spectrum porosity and the hydrocarbon characteristic ratio obtained by the gas logging data, and then the oil and water layer of the volcanic reservoir can be recognized.

Description

technical field [0001] The invention relates to the technical field of logging evaluation of complex oil and gas reservoirs in petroleum exploration, in particular to an oil-water analysis based on nuclear magnetic logging and gas logging data in the logging evaluation of volcanic rock reservoirs with complex lithology and low porosity and low permeability. layer identification method. Background technique [0002] The identification of oil and water layers in volcanic rock reservoirs is one of the difficulties encountered in well logging science. The main method of traditional logging oil and water layer identification is the resistivity method. This traditional method increases the uncertainty of fluid identification in volcanic rock reservoirs, which is mainly reflected in the following points: [0003] 1. The lithology of volcanic rocks varies greatly, and the resistivity of different lithologies varies greatly. This difference can sometimes reach several orders of magn...

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Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a method for identifying oil and water layers suitable for volcanic rock reservoirs, which can realize the difference spectrum porosity obtained by processing nuclear magnetic logging data when the traditional resistivity method cannot effectively identify oil and water layers , and then establish a crossplot with the characteristic ratio of hydrocarbons obtained from gas logging data, realizing the effective identification of oil and water layers in volcanic rock reservoirs

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