Method for quantitatively evaluating shale gas sweet points

Abstract

A method for evaluating shale gas sweet points is disclosed. The method comprises the following steps of determining geological sensitive sweet point parameters and engineering sweet point parametersaccording to the basic geological data, the logging data and the seismic data; carrying out geophysical prediction based on the confirmed geological sensitive sweet point parameters and the engineering sweet point parameters to obtain a prediction result; establishing a shale gas sweet point quantitative evaluation model Q; determining a quantitative evaluation factor Qsweet of the shale gas sweetpoints; and judging the beneficial exploration area of the shale gas according to the numerical range of the evaluation factor Qsweet. According to the method, through establishing the sweet point quantitative evaluation model, the shale gas sweet point comprehensive evaluation in a complex-structure area can be completed, the enriched high-yield zone is preferably selected, and the efficient exploration and development are facilitated.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration, and more particularly, to a method for quantitatively evaluating shale gas sweet spots. Background technique [0002] Shale gas belongs to unconventional natural gas, which mainly occurs in the shale and shale formations with hydrocarbon-generating capacity in the adsorption and free state. Shale is very different from conventional reservoirs in mineral composition, petrophysical properties and seepage characteristics. Therefore, traditional reservoir evaluation methods are not fully applicable to shale gas layers, and the evaluation contents are also different. Exploration practice has confirmed that shale gas reservoirs show strong heterogeneity vertically and horizontally, and there are local high-yield enrichment areas. At present, the most important factors for the prediction and evaluation of shale gas sweet spots at home and abroad include total organic carbon content (TOC...

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Problems solved by technology

[0003] (1) For the parameter evaluation of shale gas sweet spots, geophysical prediction is the main focus, and the research is also relatively in-depth. Geological sweet spot prediction technology includes TOC, pressure coefficient, gas content prediction, etc. Engineering sweet spot prediction technology includes brittleness index prediction, etc. Geological and The dessert evaluation system combined with engineering is not yet perfect;

[0004] (2) Compared with North American shale gas fields, the enrichment and preservation of marine shale gas in southern China is controlled by preservation conditions. Therefore, in the process of comprehensive evaluation of shale gas sweet spots, the pressure coefficient and shale gas The development density of fractures in the roof of the bed has not been introduced into the existing quantitative evaluation model of shale gas sweet spots with quantitative standards

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