Karst detection method combining three geophysical methods and two geological methods

Abstract

The invention relates to the field of shale gas pre-drilling exploration, in particular to a karst detection method combining three geophysical methods and two geological methods: S1, carrying out engineering geological and hydrogeological surveys to obtain comprehensive geological information; S2, transforming the underground space from shallow The depth is divided into the first, second and third burial depth intervals, and the integrated observation system of geophysical data is designed; S3, according to the integrated observation system of geophysical data, respectively: high-density electrical method, TEM, AMT data acquisition and data processing inversion, Obtain the first, second and third apparent resistivity profiles; step 4, determine the karst development range in the first, second and third burial depth intervals; step 5, synthesize the first, second and third burial depth intervals According to the karst development range and comprehensive geological information, the karst development range shallower than the third buried depth interval is determined. The invention expands the detection depth limitation problem of using a single geophysical exploration method, realizes the complementary advantages of multiple geophysical exploration methods, and improves the risk identification accuracy.

Description

technical field [0001] The invention relates to the field of shale gas pre-drilling exploration, in particular to a karst detection method combining three geophysical methods and two geological methods. Background technique [0002] China's shale gas is mainly in the Sichuan Basin, accounting for 60% of the country's production. At present, shale gas production is mainly concentrated in southern Sichuan. In 2014, large-scale development of shale gas began, and 3 billion cubic meters of shale gas has been built in 2016. production capacity. The "Shale Gas Exploration and Development Pilot Area in the Southern Sichuan Region of Sichuan Province" and the "Sichuan Changning-Weiyuan National Shale Gas Demonstration Area" have become national-level pilot areas and demonstration areas. [0003] The southern part of Sichuan Province belongs to the middle-alpine area, with deep topography and large height difference. The target layer for shale gas development is generally buried at ...

AI Technical Summary

Problems solved by technology

At present, in the existing technologies at home and abroad, a single geological survey method, geophysical exploration method or simple geophysical prospecting + geological method are mostly used for karst exploration before shale gas drilling, and there are still limitations in detection depth, identification resolution and interpretation accuracy. defect

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