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通过总结分析水对不同生烃模拟实验体系实验产物演化机理的影响,进一步明确了水在有机质演化过程中的作用。生烃模拟实验系统的发展历程为:开放体系→封闭体系→半开放体系,实验介质也由无水模拟发展到加水模拟。研究表明半开放体系下的加水生排烃模拟实验更贴近常规油气实际地质演化过程。液态水在不同温度具有不同的性质,常温液态水(一般T<100℃)、高温液态水(200~374.5℃)及超过临界点(临界温度T=374.5℃和临界压力P=22.1MPa)的超临界状态水的物理和化学性质均存在较大差异。实验中模拟温度一般都高于200℃,水在不同实验系统条件下具有不同的存在状态,对模拟产物也有不同作用。总体来讲,封闭体系下,水对生烃演化有一定的促进作用,并且气态烃产率与加水量呈正相关关系,而液态烃产率在加水量相当于岩样的20%~50%时最大;相对而言,半开放体系下,高压水蒸汽介质更有利于气态烃的生成,而高温高压条件下的临界态水则更有利于液态烃的生成和保存。所以,综合前人实验结果,总结水介质参与下的不同生烃模拟实验系统产物特征,将为明确水对有机质演化机理的作用提供重要的理论依据。
By analyzing the influence of water on the evolution mechanism of experimental products in different hydrocarbon generation experimental systems, the role of water in the evolution of organic matter is further clarified. The development history of hydrocarbon generation simulation experiment system is: open system → closed system → semi-open system. The experimental medium is also developed from anhydrous simulation to water simulation. The research shows that the simulation experiment of adding hydro-expulsion under the semi-open system is closer to the actual geological evolution of conventional oil and gas. Liquid water has different properties at different temperatures. Liquid water at normal temperature (generally T <100 ℃), liquid water at high temperature (200-374.5 ℃) and liquid water exceeding the critical point (T = 374.5 ℃ and critical pressure P = 22.1MPa) The physical and chemical properties of water in the supercritical state are quite different. In the experiment, the simulation temperature is generally higher than 200 ℃. Water has different states under different experimental conditions and has different effects on the simulated products. Generally speaking, water has a certain promotion effect on hydrocarbon generation and evolution in closed system, and the yield of gaseous hydrocarbon is positively correlated with the amount of water added, while the yield of liquid hydrocarbon is about 20% ~ 50% In the semi-open system, high-pressure steam is more conducive to the formation of gaseous hydrocarbons, while the critical state water under high-temperature and high-pressure conditions is more conducive to the formation and preservation of liquid hydrocarbons. Therefore, based on the previous experimental results, summarizing the product characteristics of different hydrocarbon generation simulated experimental systems with the participation of water medium will provide an important theoretical basis for clarifying the effect of water on the evolution mechanism of organic matter.