Excavation effect quantitative characterization and gas-bearing property evaluation method for compact sandstone low-resistance reservoir

Abstract

The invention discloses an excavation effect quantitative characterization and gas-bearing evaluation method for a compact sandstone low-resistance reservoir, belongs to the technical field of geophysical well logging evaluation, breaks through the difficulty that the excavation effect can only be qualitatively described for a long time, and solves the problems that in the prior art, the gas-bearing property evaluation effect of the compact sandstone low-resistance reservoir is not ideal, and the evaluation precision is difficult to meet the production requirements. The excavation effect quantitative characterization method for the compact sandstone low-resistance reservoir mainly comprises the steps that: the total hydrogen index Hgt of gaseous hydrocarbon is calculated according to gas logging data, and the shale content Vsh, the effective porosity phi e, the water saturation Sw and the total hydrogen index HNH in a stratum are calculated according to logging data; then an excavationeffect index Hex in the stratum is calculated by utilizing the parameters Hgt, Vsh, phi e, Sw and HNH; and then the gas-bearing property of the compact sandstone low-resistance reservoir is evaluatedaccording to Hex. According to the method, qualitative description to quantitative characterization of the excavation effect phenomenon is achieved, the precision and reliability problems of evaluation of the gas-bearing property of the compact sandstone low-resistance reservoir are solved, and a good application effect is achieved in Jinhua-Qiulin block jurassic Shaximiao formation.

Description

technical field [0001] The invention belongs to the technical field of geophysical well logging evaluation, relates to the exploration and development of natural gas, in particular to the quantitative characterization of the excavation effect of tight sandstone low-resistivity reservoirs and the gas-bearing property evaluation method. Background technique [0002] In recent years, through in-depth exploration and reexamination of old wells, remarkable exploration results have been achieved in the Jurassic in the Jinhua-Qiulin block of the Sichuan Basin. Obtain high-production gas wells. The statistics of lithoelectric experiments and resistivity logging data show that the tight sandstone reservoirs in this area have low resistivity, and the traditional water saturation (S w ) single-parameter method, porosity and water saturation / resistivity crossplot and other gas-bearing evaluation methods cannot meet the reliability and accuracy requirements of tight sandstone low-resist...

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Problems solved by technology

The difference spectrum method and shift spectrum method based on nuclear magnetic resonance logging data can effectively identify gas layers, but this method is not suitable for comprehensive development due to the high cost of nuclear magnetic resonance logging

In a word, the research on gas layer mining effect in the existing technology is not deep enough, and most of them are still at the qualitative description level, and the logging information needs to be deeply excavated

The above gas-bearing property evaluation methods are not effective in evaluating the gas-bearing properties of tight sandstone low-resistivity reservoirs like the Jurassic Shaximiao Formation in the Sichuan Basin, and the evaluation accuracy cannot meet production needs

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