地质盆地金属氧化物还原作用及其识别和对油气的影响  

High-valence metal oxide reduction reaction,identification,and its impact on petroleum accumulation

作　　者：帅燕华[1] 李剑[1] 陶小晚[1] 胡国艺[1] 米敬奎[1] SHUAI Yanhua;LI Jian;TAO Xiaowan;HU Guoyi;MI Jingkui(Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2024年第12期2228-2239,共12页Natural Gas Geoscience

基　　金：国家自然科学基金(编号:42272139,41772135);中国石油基础性前瞻性项目(编号:2021DJ0604,YGJ2019-04-02)联合资助。

摘　　要：油气作为强还原剂,在地质盆地中容易被各类氧化剂氧化,如热硫酸盐还原作用(TSR)、高价态金属氧化物还原作用等,这些都是烷烃被氧化的典型例子。虽然后者氧化能力更强,易于发生在碎屑岩与火成岩储集体中,但却未获得广泛关注。这是因为其反应产物与有机质热裂解产物相似,为碳数更小的有机质(含烷烃)、CO_(2)和水,从而造成识别难度大。然而,高价态金属氧化物还原作用对改变油气组成和特征、干扰油气来源与成藏规律认识具有重要意义;同时,其产生的酸性流体能够改善储集体储集性能,导致储层非均质性,是深部优质储层和油气高效聚集的可能影响因素。从模拟实验出发,对高价态金属氧化物还原反应机理、影响因素、鉴别与示踪及对储层改造等进行初步分析,并提出烷烃分子内同位素、伴生CO_(2)同位素与碳酸盐胶结等可作为示踪指标。基于富含高价态金属氧化物的红色碎屑岩与风化壳型火成岩广泛分布的特征,指出该反应具有普遍性和重要性,希望能对碎屑岩及火成岩油气藏的成藏机制、储层预测及油气田的高效开发有所帮助。Alkanes,as strong reducing agents,are easily oxidized by various oxidants in geological basins,with thermal sulfate reduction(TSR)in carbonate areas being a typical example.The reduction reaction of high-va⁃lence metal oxides can more effectively oxidize alkanes,particularly in clastic and weathered igneous reservoirs,but this reaction has not received widespread attention.Like the thermal decomposition of organic matter,it is difficult to directly identify this reaction based on products like small carbon-number organics,CO_(2),and water.This reaction significantly alters the composition and characteristics of oil and gas,complicating the understand⁃ing of their origin and filling mechanisms.It generates acidic fluids,CO_(2),improves reservoir storage perfor⁃mance,and induces heterogeneity,which are crucial for deep high-quality reservoirs and efficient oil and gas ac⁃cumulation.It also plays a key role in the carbon cycle.This paper preliminarily analyzes the mechanism,influ⁃encing factors,identification,tracing indicators,and reservoir modification of the high-valence metal oxide re⁃duction reaction based on simulation experiments and field data.It suggests that intramolecular isotopes of al⁃kane molecules,associated CO_(2),and carbonate cementation can be used as tracing indicators.Given the wide⁃spread distribution of red clastic rocks and weathered crust-type igneous rocks,this reaction is likely very wide⁃spread.This understanding aims to enhance knowledge of reservoir formation mechanisms,reservoir predic⁃tion,and the efficient development of clastic and igneous rock oil and gas reservoirs.

关 键 词：碎屑岩 火成岩 金属氧化物还原作用 油气示踪 储层改造 

分 类 号：TE135[石油与天然气工程—油气勘探]