部分辽河稠油油藏中含氧化合物的分布

Occurrence and distribution of oxygenated compounds in some heavy oil reservoirs of Liaohe basin.

非烃化合物作为石油的重要组成部分 ,在油藏地球化学研究中应受到足够的重视。在辽河油田冷 4 3块北部雷家场地区、牛心坨油田茨榆坨地区、高升油田高Ⅰ区和高Ⅲ区的沙一段到沙四段 10个稠油样品中 ,酸性馏分占正己烷可溶性非烃馏分的 70 %以上。由气相色谱可检测非烃化学组成的分析结果可知 ,辽河稠油中有着丰富的非烃化合物类型 ,其中各类含氧化合物占总非烃的 92 %～ 97%。含氧化合物的存在和分布特征表明 ,这些稠油油藏接受了非母岩来源的近期菌藻类有机质输入。以正构羧酸和甾醇为例 ,指出含氧化合物的存在与分布不是由油藏的原始油源 (母源岩 )所决定的 ,也不能简单地以油藏所在区域来划分 ,而很可能与发生在储集层中的、受到储集层构造条件控制的后期地球化学过程 (如后期有机质输入、生物降解和水洗作用等 )有关。原油中含氧化合物的化学组成与储集层构造条件相关这一特性为多方面的油藏地球化学研究提供了基础性条件。

Nonhydrocarbon as significant constituents in crude received up t o today much insufficient geochemistry studies in the past. The attempt of this paper is to illustrate the significance and potential availability of nonhydroca rbon in reservoir geochemistry research through studies on the occurrence and di stribution of oxygenated compounds of some heavy oil reservoirs in Liaohe basin, China, i.e. ten heavy oil samples from the S 1+2 , S 3 and S 4 reservoirs of the Leijiachang unit in the north part of Block Leng 43 of Liaohe oil field ,the Ciyutuo unit of Niuxintuo oil field, and the Unit Gao? Ⅰ and Gao? Ⅲ o f Ga osheng oil field. Polar nonhydrocarbon fraction accounts for 40-60% of the heavy oils studied, in which acidic fraction accounts for more than 70% of the he xane soluble polar fraction. The results of gas chromatographic and combined gas chromatographic mass spectroscopic analyses show that the heavy oils in Liaohe basin are of various classes of nonhydrocarbon. Oxygenated compounds account for 92-97% of the GC amenable nonhydrocarbon, among them carboxylic acids constitu te the main proportion. The occurrence and distribution of oxygenated compounds reveal that the heavy oil reservoirs have received significant recent input of o rganic matter of aquatic origin in addition to the oils filled into them from th e sources. The occurrence and distribution pattern of oxygenated compounds in th e crude oil, especially those of fatty acids and sterols, cannot be simply attri buted to the source of the primarily charged oils or the location of the reservo irs, signifying a reservoir dependence related to geochemical processes having t aken place in the reservoirs, such as the recent organic input, biodegradation a nd oxidation through underground water flush. The fact that the occurrence and distribution pattern of oxygenated compounds are related to the structure and pr eservation environment of reservoir implies them prospective important roles in reservoir geochemistry studies.