C-O-H体系高温高压流体相组成的热力学研究

THERMODYNAMIC STUDY ON THE COMPOSITIONS OF HIGH-TEMPERATURE AND HIGH-PRESSURE FLUID PHASES IN THE C-O-H SYSTEM

本文在C－O－H体系流体相平衡基础上，利用现有的热力学数据和新的p－V－T资料，在pT=∑pi假定下，计算了高温、高压条件下流体相组成。结果表明，该体系主要存在五种流体相，在不同温压条件下各流体相所占比例不同。在相对较低的温、压条件下，CH4是体系中占主要的流体相（约占70％），且随温、压和氧逸度的升高，它所占比例却明显降低，所获结果为探讨无机成因天然气形成的可能性、存在的量比和稳定存在的物理化学条件提供了充分的理论依据。

Based on fluid phase equilibrium in the C-O-H system,the compositions of various fluid phases under high temperatures and high pressures have been calculated in terms of the available thermodynamic data and new p-V-T data and on the assumption of pT=pi in this paper. The results indicate that in this system there are 5 major fluid phases with different proportions at various T and p. CH4 is the dominant phase (about 70% ) under relatively low T and p. Its proportion obviously decreases with inereasing T, p and fo2. The results provide sufficient theoretical evidence for the possibility of CH4 formation and the physical-chemical conditlons of its stable occurrence and proportion under geological environment.