Shale gas physical geography quick evaluation method

Abstract

The invention discloses a shale gas physical geography quick evaluation method. The geologic factors of production of shale gas are as follow: clay, kerogen, porosity, water saturation and permeability, and according to the above geologic factors, evaluation calculation with different models is performed: in the conventional well logging interpretation, the content of clay is calculated by a uranium-free gamma ray curve; the formation of kerogen is mostly in the reduction environment with relatively high content of the radioactive element U, so that a peak appears in the natural gamma ray curve, and as the density of kerogen is relatively low, TOC is integrally calculated with several methods; the value of porosity is calculated by a neutron-density crossplot, and the amount of minerals in rock can also be calculated through correction of the crossplot; the water saturation is calculated by the Archie's formula; and the permeability is calculated according to regression of porosity, and only the shale segment reservoir bed is subjected to regression. The shale gas physical geography production factors can be quickly and accurately calculated, and the results are accurate.

Description

technical field [0001] The invention relates to a method, in particular to a method for rapid evaluation of shale gas geophysics. Background technique [0002] Shale gas is an unconventional natural gas that occurs in organic-rich mud shale and its interlayers. It mainly exists in adsorption and free states. The main component is methane. It belongs to the same category as "coalbed methane" and "tight gas". . The formation and enrichment of shale gas has its own unique characteristics, and it is often distributed in thick and widely distributed shale source rock formations in the basin. Shale gas has been recognized by people for a long time, but it is more difficult to collect than traditional natural gas. With the increasingly scarce resources and energy, as a beneficial supplement to traditional natural gas, people gradually realize the importance of shale gas. Shale gas exists in kerogen, clay particles and pore surfaces in an adsorbed state (about 50%), and a very sma...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the low efficiency of the above-mentioned existing evaluation methods, and the inaccurate measurement results of physical factors, which cause the problem that shale gas exploitation is very inconvenient, and a method for rapid evaluation of shale gas geophysics is designed. It can accurately and quickly measure the geophysical generation factors of shale gas, and the results are accurate, so that the subsequent shale gas exploitation can be conveniently mined according to the measurement results, which solves the problem of the low efficiency of the existing evaluation methods and the inconsistency of the measurement results of physical factors. Accurate, causing very inconvenient problems in shale gas extraction

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