辽河探区西部凹陷原油溶解气逸出及其成藏意义

Escape of the dissolved gas in crude oil in the western sag of Liaohe exploration zone and its significance to the formation of natural gas pool

通过辽河探区西部凹陷原油溶解气油比变化特征及其与原油密度关系,分析了原油溶解气逸出量分布与油气成藏的关系.原油溶解气油比一般随深度增加而增大,随深度变浅而降低,与原油密度有较好的相关性.依据原油密度与原油溶解气油比相关的数学模型确定了单位质量原油溶解气逸出量及其分布特征.凹陷内部的单位质量原油溶解气逸出量相对较小,但保存条件好,有利于气藏的形成;而凹陷边缘单位质量原油溶解气逸出量一般较高,但保存条件差,对天然气成藏不利.

Based on the variation feature of the ratio of the dissolved gas to crude oil and the relation between the variation feature and the density of the crude oil in the western sag of Liaohe exploration zone,the relationship between the distribution of the escaped gas and the formation of natural gas pool.The ratio of the escaped gas to the crude oil will increase with the depth of oil reservoir,and there is better relativity between the ratio of the escaped gas to the crude oil and the density of crude oil.The escaping amount of the dissolved gas in the crude oil of unit mass and its distribution are determined according to the relation formula between the ratio of the escaped gas to the crude oil and the density of crude oil.The escaping amount of the dissolved gas in the crude oil of unit mass is less in the center part of the sag but the preservation conditions of it are good,which is favorable to the formation of gas pool.While in the border of the sag,the escaping amount of the dissolved gas in the crude oil of unit mass is greater but the preservation conditions of it are poor,which is unfavorable to the formation of gas pool.