Deep shale gas fracturing effect prediction method based on mutation theory

Abstract

The invention discloses a deep shale gas fracturing effect prediction method based on a mutation theory. The method comprises the steps that all influence factors are divided into geological factors and engineering factors; classifying and sorting the factors according to the mutation theory and the contribution degrees of the factors, and establishing a shale gas horizontal well fracturing effect evaluation model in combination with the mutation theory; and performing positive and negative index standardization on each factor, and calculating through a bifurcation point equation to obtain a total evaluation index. According to the method, the problem that the fracturing construction effect is not ideal due to the fact that only geological factors are considered in a traditional fracturing effect prediction method is solved, and the problem that the traditional fracturing effect prediction method needs to know the specific proportion of each factor in the fracturing effect influence is solved. Compared with a traditional fracturing effect prediction method which is large in calculation amount and large in prediction result interference, the method provided by the invention is simple and practical in calculation process and accurate in prediction result, and has practical value.

Description

technical field [0001] The invention relates to the technical field of oil and gas development, in particular to a prediction method for deep shale gas fracturing effects based on catastrophe theory. Background technique [0002] With the deepening of oil field development, the difficulty of oil and gas reservoir development gradually increases. The proportion of low-permeability and ultra-low-permeability oil and gas reservoirs in new proven reserves is increasing year by year, and the development cost is also increasing. Fracturing is an important technical measure for increasing production of oil and gas wells. Shale has the characteristics of low permeability and low porosity, so it is necessary to implement fracturing technology for production stimulation measures. At present, the geological structure of deep shale gas reservoirs is complex, and it is difficult to identify sweet spots. At the same time, the geological conditions of shale gas reservoirs are poor. It is ...

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Problems solved by technology

Conventional evaluation methods take geological conditions as the main consideration, and cannot consider the feasibility of fracturing construction, which may result in ineffective fracturing. Therefore, although there have been many researches and accumulations on fracturing technology, fracturing is carried out purely based on experience. The effect prediction still has a certain degree of blindness and subjectivity, which may cause a large difference in the effect prediction after fracturing, and even lead to construction failure, which will bring huge economic losses to the oil field

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