INTERACTIONS BETWEEN ORGANIC-ACID ANIONS IN FORMATION WATERS AND RESERVOIR MINERAL PHASES
INTERACTIONS BETWEEN ORGANIC-ACID ANIONS IN FORMATION WATERS AND RESERVOIR MINERAL PHASES
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DOI：
10.1016/0146-6380(92)90012-m
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发表时间：
1992-12-01
影响因子：
3
通讯作者：
RIIS, M
中科院分区：
文献类型：
--
作者：
BARTH, T;RIIS, M
对挪威大陆架的地层沃茨进行了短链有机酸阴离子分析。乙酸是主要成分，在未受污染的地层水样品中观察到的水平在0.3-20 mM范围内。对各个储层和地层随时间和区域的研究表明，对于大量流体，每个单元内的酸分布相当均匀。在含有生物降解油的储层中，有机酸阴离子水平通常较低。统计分析表明，有机酸阴离子含量与无机离子含量呈负相关，有机酸阴离子的主要作用是增加矿物相的稳定性。实验室实验也已进行，并显示出类似的效果，砂岩样品。在氧化条件下，有机酸物质的缓冲能力也很重要，因为它可以防止由于黄铁矿氧化而导致的极端pH条件的发展。在碳酸盐体系中，几乎没有观察到系统效应。天然系统和实验室实验的结果表明，地层沃茨有机酸的存在不会促进储集岩中次生孔隙的发育。所观察到的关系表明，随着有机阴离子水平的增加，地层沃茨中无机离子的浓度水平降低，因此矿物稳定性增加。
Formation waters from the Norwegian continental shelf have been analysed for short-chain organic acid anions. Acetic acid is the major component, and the observed levels are in the range 0.3-20 mM in uncontaminated formation water samples. Studies of individual reservoirs and formations over time and area show a quite uniform distribution of the acids within each unit for large volumes of fluid. The organic acid anion levels are generally low in reservoirs containing biodegraded oil. Statistical analysis has been used to find correlations between the organic and inorganic ion compositions and the reservoir conditions and shows a dominating negative correlation between the organic acid anion levels and the levels of inorganic ions, indicating that the main effect of the organic ions is to increase the stability of mineral phases. Laboratory experiments have also been performed and show similar effects for sandstone samples. Under oxidizing conditions the buffering capacity of the organic acid species is also important, as it prevents the development of extreme pH conditions caused by pyrite oxidation. In carbonate systems few systematic effects were observed. The results, both for the natural systems and the laboratory experiments, show that the presence of organic acids in the formation waters does not contribute to the development of secondary porosity in the reservoir rock. The observed relationships rather indicate decreasing concentration levels of inorganic ions in the formation waters with increasing levels of organic anions and thus an increase in mineral stability.