三塘湖盆地牛圈湖油田原油物性特征及其影响因素分析

Property of the crude oil in Niujuanhu Oilfield of Santanghu Basin and its control factors

在对三塘湖盆地牛圈湖油田原油物性分布特征分析的基础上,结合油气藏构造条件、运移条件和保存条件等,分析原油物性差异的原因,发现牛圈湖油田侏罗系与芦草沟组原油物性的特征在深度上有较大差别.侏罗系原油埋藏深度相对较浅,相对密度和黏度随深度增加而降低,主要是轻组分运移散失、水洗、氧化等作用的结果.芦草沟组原油埋藏深度相对较大,相对密度和黏度则随深度增加而升高,主要是油气藏中油气重力分异作用的结果.芦草沟组油气藏的保存条件总体要好于侏罗系.在分析原油物性时,还应注意采样、分析时间对分析结果的影响.

Based on the analysis of the property distribution of the crude oil,and combining with the tectonic setting,migration conditions,and reservation conditions of the petroleum pool,the cause why there is difference in the physical properties of the crude oil is analyzed.It is found that there is great difference in the depth between the physical property of Jurassic crude oil and Lucaogou Formation crude oil.The burial depth of the Jurassic crude oil is relatively shallow,and its relative density and viscosity decrease with the increase of the its burial depth,which is the result of the migration dissipation,water washing and oxidation of the light components of the crude oil.The burial depth of Lucaogou Formation crude oil is relatively deep,and its density and viscosity increase with the increase of its burial depth,which is the result of the gravity differentiation in petroleum pool.The result indicates that the reservation conditions of Lucaogou Formation petroleum pool are better than Jurassic petroleum pool.In addition,the effects of sampling and analysis time on the analysis results should be taken attention in the analysis of the crude oil physical properties.