摘要
塔里木盆地在埋深超过8000 m、油藏经历200℃以上高温改造仍然发现液态烃类流体稳定存在,目前勘探工作正在面向深层-超深层拓展,塔里木盆地海相原油具有的高热稳定性来自其较好的保存条件。本文总结了近年来塔里木盆地海相油藏研究进展,结合宏观地质背景演化,主要从微观过程入手探讨塔里木盆地海相油藏热稳定性的地球化学特征。认为宏观上塔里木盆地目前的低地温梯度有利于油藏的稳定保存;而油藏储层中普遍缺乏氧化性矿物,石膏类等含硫矿物也贫乏,使得油藏储层中的烃-水-岩相互作用(包括热化学硫酸盐还原反应)发生的程度有限;同时,塔里木盆地海相油藏中地层水广泛发育、分布复杂,这对油藏中的液态烃类,特别是大分子烃类的热裂解具有抑制作用,从而有利于油藏的稳定保存。有必要进一步开展针对塔里木盆地海相原油热稳定性的微观地球化学特征探讨,特别是烃-水-岩相互作用中有利于原油烃类流体稳定保存的物理化学机理分析,研究成果将有助于深化塔里木盆地深层-超深层油气藏的勘探研究工作。
Some liquid hydrocarbon fluids were found to be still thermally stable and occur in the Tarim Basin, NW China, even over the burial depth of 8000 m or the oil reservoirs experienced temperature more than 200 ℃. Therefore, recently more exploration studies have been targeted to the deeper strata in order to find more marine crude oils in the Tarim Basin. High thermal stability of crude oil reservoirs in the Tarim Basin may be due to their fairly well preservation after accumulation. Based on the recent exploration progress in the Tarim Basin, this paper is aimed to probe the geochemical features of the thermally stable crude oil reservoirs concerning both their geological background and micro physiochemical properties of the petroleum fluids. It’s concluded that the low geothermal gradient in the Tarim Basin is the most important factor in influencing the preservation of the petroleum, and the common absence of oxide minerals in the reservoirs is another key factor for the extensive occurrence of the crude oil reservoirs. Furthermore, the formation water extensively occurred in the reservoirs throughout the Tarim Basin, is also favorable to the petroleum preservation because inside the oil reservoir water will inhibit the thermal degradation of hydrocarbons to some degree. More work should be focused on the study of physiochemical reaction mechanisms of hydrocarbon-water-rock interactions, especially for the evaluation of relative importance of the radical reaction and the carbon cation mechanisms during these chemical reactions, and thus the constrained factors for thermal stability of the crude oils in the Tarim Basin will be probed by using the geological reservoir rocks, the formation water and the crude oils. This kind of work will be helpful to the further exploration studies targeted to the deep marine crude oil reservoirs in the Tarim Basin, NW China.
出处
《地球化学》
CAS
CSCD
北大核心
2015年第2期189-195,共7页
Geochimica
基金
国家自然科学基金(41472109
41272149)
作者简介
廖泽文（1969–）,男,研究员,有机地球化学专业.
