渤海蓬莱9-1油田强烈生物降解原油油源对比

发布时间：2018-11-13 10:44

【摘要】：渤海海域近年来在中生界潜山、新近系等层系发现了大量的稠油油藏,但原油因遭受强烈的生物降解,导致一些常用的油源对比指标失效而使油源对比困难。以蓬莱9-1大型稠油油田为例,研究了强烈生物降解对原油碳同位素、饱和烃、芳烃生物标志化合物及含氮化合物的影响,引入降解指数C2925-降藿烷/C30藿烷定量表征强烈生物降解原油的降解程度,结果表明:强烈生物降解会造成伽马蜡烷和咔唑含量的降低;C19三环萜烷、C24四环萜烷和Ts的优先降解会导致C19/C23三环萜烷、C24四环萜烷/C26三环萜烷参数明显减小和ETR参数明显增大;4-甲基三芳甾类为强烈生物降解原油中最稳定的生物标志物,C274-甲基三芳甾类、C294-甲基-24-乙基三芳甾类和C294,23,24-三甲基三芳甲藻甾类对烃源岩的生源构成及沉积环境具有指示意义,结合全油碳同位素可有效区分沙三段、沙一段和东营组等3套烃源岩及其生成的原油;咔唑及原油物性变化规律反映了油气的运移方向。蓬莱9-1油田潜山原油来源于渤东凹陷沙三段和沙一段烃源岩,新近系原油主要来源于沙一段烃源岩,为渤东凹陷和庙西凹陷的共同贡献。本文研究结果对研究区下步勘探具有指导意义,为其他类似地区强烈生物降解原油的油源对比提供了方法借鉴。
[Abstract]:In recent years, a large number of heavy oil reservoirs have been discovered in Mesozoic buried hill, Neogene and other strata in the Bohai Sea area. However, the crude oil is subjected to strong biodegradation, which leads to the failure of some commonly used oil source correlation indexes, which makes the oil source correlation difficult. Taking Penglai 9-1 heavy oil field as an example, the effects of strong biodegradation on carbon isotopes, saturated hydrocarbons, aromatics biomarkers and nitrogenous compounds in crude oil were studied. The degradation degree of strongly biodegradable crude oil was quantitatively characterized by introducing degradation index C2925-norbarane / C30 hopane. The results showed that the content of gamma-alkane and carbazole would be decreased due to the strong biodegradation. The preferential degradation of C19 tricyclic terpene, C24 tetracyclic terpene and Ts would result in C19/C23 tricyclic terpene, C24 tetracyclic terpene / C26 tricyclic terpene parameter decreased and ETR parameter increased obviously. 4- methyl triarosterols are the most stable biomarkers in highly biodegradable crude oil, C274-methyl triarosterols, C294-methyl-24ethyl triarosteric and C294233-trimethyl-triarbosteric have indicative significance for the source composition and sedimentary environment of source rocks. Combined with the whole oil carbon isotopes, the third member of Sha formation can be effectively distinguished. Three sets of source rocks and their generated crude oil in Shayi member and Dongying formation; The changes of carbazole and crude oil physical properties reflect the migration direction of oil and gas. The buried hill crude oil in Penglai 9-1 oilfield is derived from the source rocks of the third member and the first member of the Shahejie formation in the Bodong Sag, and the Neogene crude oil mainly comes from the source rock of the first member of the formation, which is the common contribution of the Bodong Sag and the Miaoxi Sag. The results of this paper are of guiding significance for the next step exploration in the study area and provide a reference for the source correlation of strongly biodegradable crude oil in other similar areas.
【作者单位】：中海石油(中国)有限公司天津分公司;中海石油(中国)有限公司上海分公司;
【基金】：“十二五”国家科技重大专项“渤海海域已证实的富生烃凹陷再评价及新领域勘探方向(编号:2011ZX05023-001-004)”部分研究成果
【分类号】：P618.13

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