轻质油藏注空气氧化特性及动力学研究

摘要/Abstract

摘要：

通过静态氧化管实验以及热重/微分热重(TG/DTG)手段研究了轻质原油在不同含氧浓度空气(21 %和8 %)以及储层岩石颗粒条件下原油氧化特征,并结合Arrhenius氧化动力学模型定量地表征各因素对原油氧化活性影响的大小.结果表明:空气中含氧浓度减小会降低氧化反应速率,储层岩石对原油氧化的催化作用促进氧化反应的进行;原油经贫氧空气氧化后剩余气体中含氧浓度显著下降,大大提高了空气驱的安全性;热动力学分析表明:原油经历了低温氧化,燃料沉积及高温氧化三个阶段,储层岩石对原油氧化的积极作用强于氧气浓度降低所产生的消极影响,可显著降低原油在贫氧空气中的活化能,这一发现有利于贫氧空气驱的推广应用.

关键词: 轻质原油, 氧化特征, 含氧浓度, 储层岩石, 氧化动力学

Abstract:

In this artide, we analyse the oil oxidation characteristics of the light oil at different oxygen concentrations(21 % and 8 %) and in the presence of the reservoir rock by the static oil oxidation tube and thermogravimetry/derivative thermogravimetry(TG/DTG). According to the Arrhenius oxidation kinetics model, the influence of the factors on crude oil oxidation activity is characterized quantitatively. The results show that the lower oxygen concentration can reduce the oxidation reaction rate, and in addition, the reservoir rock has strong catalytic impacts on oil oxidation, which can promote the oxidation reaction. The oxygen concentration of the remaining gas drops significantly after the oxidation in a lower oxygen concentration, which greatly improve the safety of air injection displacement. The thermal analysis shows that the crude oil exhibits three stages of low temperature oxidation, fuel deposition and high temperature oxidation. The positive impact of cuttings on the crude oil oxidation is stronger than the negative impact of the lower oxygen concentration, which can significantly reduce the activation energy of crude oil at low oxygen environment. It is benefit to the application of lean oxygen injection displacement.

Key words: light oil, oxidation characteristic, oxygen concentration, reservoir rock, oxidation kinetics

中图分类号:

TE357.7

蒲万芬,顾飞,宋戈,刘鹏刚,刘哲知. 轻质油藏注空气氧化特性及动力学研究[J]. 油气藏评价与开发, 2018, 8(2): 35-40.

Pu Wanfen,Gu Fei,Song Ge,Liu Penggang,Liu Zhezhi. Research on oxidation characteristics and kinetics of light oil reservoir during the process of air injection[J]. Reservoir Evaluation and Development, 2018, 8(2): 35-40.

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参考文献 15

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样品	黏土矿物质量分数	其他矿物质量分数
样品	黏土矿物质量分数	石英	钾长石	斜长石	方解石	白云岩
岩石颗粒	10.74	38.81	6.59	36.27	2.86	4.73

样品	初始压力/MPa	最终压力/MPa	温度/℃	气相组成,%				耗氧速率/(%·d^-1)
样品	初始压力/MPa	最终压力/MPa	温度/℃	O₂	N₂	CO₂	CO	耗氧速率/(%·d^-1)
原油+空气	40.19	36.46	102	14.31	84.6	0.85	0.05	0.669
原油+空气+岩石颗粒	40.38	34.87	102	12.82	84.89	1.12	0	0.818
原油+贫氧空气	40.11	37.96	102	6.89	92.71	0.26	0.03	0.111
原油+贫氧空气+岩石颗粒	40.24	36.56	102	4.93	93.66	0.813	0.04	0.307

样品	低温氧化(LTO)			燃料沉积(FD)		高温氧化(HTO)
样品	温度区间/℃	峰值温度/℃	质量损失,%	温度区间/℃	质量损失,%	温度区间/℃	峰值温度/℃	质量损失,%
原油	25~127	97	5.08	127~412	63.05	412~492	455	26.26
原油(含氧8 %)	25~112	92	4.89	112~412	71.72	412~497	459	18.12
原油+岩石颗粒	25~162	126	4.73	162~401	34.38	401~476	431	11.62
原油+岩石颗粒 (含氧8 %)	25~156	121	4.28	156~401	36.68	401~541	451	11.01

样品	线性拟合斜率		活化能 /(kJ·mol^-1)		阿伦纽斯常数 /min^-1
样品	LTO	HTO	LTO	HTO	LTO	HTO
原油	-3 346.26	-4 941.03	64.07	94.61	1.97×10⁷	1.70×10⁶
原油(含氧8 %)	-4 422.50	-5 352.90	84.68	102.49	1.59×10¹⁰	5.59×10⁶
原油+储层岩石	-1 799.76	-1 851.37	34.46	35.45	195.89	14.42
原油+储层岩石(含氧8 %)	-2 148.73	-2 298.37	41.14	57.41	2.95×10³	437.86