A Reservoir Pore Structure Classification Method Based on NMR Three Component Percentages

Abstract

The invention relates to a method for a classifying pore structure of reservoirs based on percentages of three nuclear-magnetic components. The method comprises the following steps: performing matched nuclear magnetic resonance and mercury injection experiments on rock core samples with different pore textures and classifying the pore textures of the rock core samples on the basis of morphological characteristics of a mercury injection curve; analyzing the change characteristics of the mercury injection curve, a nuclear magnetic resonance T2 spectrum and an accumulated porosity curve of the rock core samples with different pore textures and confirming the key factors controlling the quality of the pore textures; extracting percentages S1, S2 and S3 of small-size, middle-size and large-size pore components in a whole pore system from a nuclear magnetic resonance experimental data; confirming a confirmation standard of the change rule of the sizes of the S1, S2 and S3 of different pore textures; and extracting S1, S2 and S3 from a nuclear-magnetic log data and quickly classifying by utilizing the confirmation standard. The nuclear-magnetic log data of thirty wells are processed by using the method provided by the invention and the coincidence rate between the acquired results and a test oil capacity result is 90%, which is increased by 16% from the coincidence rate acquired by using the prior art.

Description

technical field [0001] The invention relates to a method for classifying reservoir pore structures based on the percentages of nuclear magnetic three components. Background technique [0002] Complicated clastic rock reservoirs with complex lithology and pore structure and low permeability are widely developed in continental sedimentary strata in my country, and their reserves account for more than 1 / 3 of my country's current total proven oil and gas resources, accounting for " About 3 / 4 of the total proven oil and gas resources since the Ninth Five-Year Plan. For quite a long time in the future, the exploration of such oil and gas reservoirs will be an important field to promote the sustained and stable growth of my country's oil and gas reserves. The pore structure of the reservoir in this kind of oil and gas reservoir is very complex, with drastic vertical and horizontal changes. Oil and gas production is poorly correlated with the porosity of the reservoir, but is close...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to solve the difficult problem of continuously classifying the pore structure of complex clastic rock reservoirs within the range of NMR logging measurement depth. Guided by the results of petrophysical experiments supporting cores, and with the help of NMR logging data, the reflected pores are extracted. The key parameters of structure type change, using the relative change law of these parameters to finally realize the rapid classification of reservoir pore structure in the continuous depth range, so as to improve the success rate of finding relatively high-yield and high-quality reservoirs under the general low porosity and low permeability background

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