Method for obtaining degree of mineralization of equivalent sodium chloride of sandstone brine layer through well logging materials

Abstract

The invention relates to evaluation on the brine grade in underground brine exploration and development, in particular to a method for obtaining the degree of mineralization of equivalent sodium chloride of a sandstone brine layer through neutron lifetime well logging materials. The method comprises the following steps that geophysical well logging is conducted on a stratum to be explained and comprises lithology class well logging, physical property class well logging and neutron lifetime well logging; a sandstone layer is divided through the lithology class well logging materials, and shale content Vsh in the sandstone layer is obtained; the porosity phi of the sandstone layer is calculated, and a brine layer and a dry layer are divided; the total capture cross section value sigma of the sandstone brine layer, the capture cross section valve sigma sh of pure mudstone and the capture cross section value sigma ma of a dry sand layer are obtained through the neutron lifetime well logging; the relation graph of the degree of mineralization of pure sodium chloride brine CNaCl and the capture cross section value sigma w is made; the degree of mineralization of the equivalent sodium chloride of the sandstone brine layer is obtained. The method has the advantages of being simple in computing method and high in precision.

Description

technical field [0001] The invention belongs to the field of geological exploration and relates to the evaluation of brine grade in underground brine exploration and development, in particular to a method for obtaining the salinity of sandstone brine layer by using neutron lifetime logging data. Background technique [0002] In the exploration and development of underground brine, after the formation is drilled, use the data obtained from well logging to interpret the brine layer and evaluate the grade of brine (the degree of salinity and the content of trace elements), which is an important work in the next step of water testing. At present, the use of logging data to classify sandstone-type water layers is very mature, including the use of natural potential (SP), natural gamma ray (GR), borehole diameter (CAL), photoelectric absorption cross-section index (PE) and other lithologic logging data to classify The sandstone layer is then divided into water layer and dry layer b...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of low measurement accuracy of brine salinity in the prior art, the present invention provides a method for obtaining the salinity of brine layer by using well logging data, especially for deep wells (≥500m) with high salinity (≥100000mg / L) The acquisition of the salinity of the brine layer has higher accuracy

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