油源判识指标研究进展及基于曲线相似性的新方法

Research progress of oil source identification index and new method based on curve similarity

油源判识方法研究对于石油甜点区的圈定及油气资源预测具有十分重要的作用。文中基于多种油源判识指标参数的归纳总结,概括了生物标志化合物、轻烃组分、碳同位素及其他4个方面的判识依据、范围及特点,提出了一种新的油源判识方法并应用于油源判识研究。生物标志化合物能判断成熟度、沉积环境等信息,由于其质量分数低,造成对微生物降解和高成熟的原油表征不清;轻烃组分能反映生烃母质来源,但指示信息单一;碳同位素可指示母质来源和运移路径,但受实验条件影响较大;其他指标,如过渡金属元素和氮同位素也有不错的应用效果。文中对基于曲线相似性原理及对至高点与至低点重新定义,通过统计28组原油样本数据计算出曲线相似性阈值为0.916,当至高点与至低点间Fréchet距离之差的绝对值小于该值即为同源。该方法从多个参数组成的曲线相似性考虑,有效降低了单一因素对判识结果的影响,具有简单、快捷和高效的特点。

The research on the method of oil source identification plays a vital role in delineating the oil sweet areas and predicting the oil and gas resources.Based on various oil source identification parameters,this paper summarizes the identification basis,range and characteristics of four indexes such as biomarkers,light hydrocarbons,carbon isotopes and others,and proposes a new oil source identification method and applies it to identify the oil source.Biomarkers can judge maturity,sedimentary environment and other information,however,due to the low mass fraction,the biomarkers cannot clearly characterize microbial degradation and high-mature crude oil.Light hydrocarbon component can reflect the source of hydrocarbon generating parent material,but its indication information is single.Carbon isotope can indicate the source and migration path of parent material,but it is greatly affected by experimental conditions.Other indicators such as transition metal elements and nitrogen isotope also have good indicating meaning for oil source analysis.In this paper,according to the principle of curve similarity and the redefinition of the highest point and the lowest point,the curve similarity threshold value is calculated to be 0.916 by counting 28 groups of crude oil sample data.When the absolute value of Fréchet distance difference between the highest and lowest point is less than this threshold value,it is homologous.Considering the curve similarity composed of multiple parameters,this method effectively reduces the influence of a single factor on the identification results,and it has the characteristics of simplicity,quickness and efficiency.