二氧化碳侵入前油气藏流体性质定量分析  

A method to analyze the reservoir fluid property before CO_2 invasion and alteration

作　　者：姜凤光[1] 王小林[2] 陈志海[1] 

机构地区：[1]中国石化勘探开发研究院,北京100083 [2]中国石油勘探开发研究院,北京100083

出　　处：《天然气地球科学》2017年第3期488-493,共6页Natural Gas Geoscience

基　　金：国家科技重大专项"CO_2驱油与埋存潜力评价及战略规划"(编号:2011ZX05016)资助

摘　　要：最近10年,在东南亚海域和南美东海岸发现一些高含CO_2的带有CO_2气顶的油环或底油油藏,对油气藏开发技术带来新的挑战。CO_2对原油中的中轻质组分的萃取作用显著,造成气顶气区以CO_2组分为主,底油或油环中的C_(7+)以上组分明显偏高,流体组成与分布特征既不同于传统的凝析气藏,又不同于混相驱油藏。基于油藏烃类取样样品组成,按照Kay混合法则、物质守恒原理及Span&Wagner状态方程等建立了CO_2充注改造前油藏流体组成恢复方法,恢复出古油藏烃类流体组成与分布,应用油藏数值模拟方法模拟CO_2充注改造油藏过程,达到平衡后获取高含CO_2油气藏的流体组成与空间分布特征。应用该方法对某深水高含CO_2油藏流体组成和空间分布进行了预测,预测结果与油藏取样结果基本相符,表明该方法是可行的。In the past ten years,some oil/gas reservoirs with high CO_2 content have been found in Southeast Asia and the east coast of South America,which bring new challenges to the development of oil and gas reservoirs.CO_2 has significant extraction effect on the light-medium weight components of the crude oil.As a result,in the gas cap,CO_2 is the major component and the molar fraction of C_（7＋） in the oil rim is very high;fluid composition and distribution characteristics are neither like conventional gas condensate reservoirs nor like oil reservoirs under miscible flooding.Based on the composition of reservoir fluid samples,according to the Kay mixing rule,conservation of substance,and Span Wagner equation of state,a method to restore the reservoir fluid composition before CO_2 invasion and alteration is built.Then fluid composition and spatial distribution of the original reservoir is restored after which CO_2 invasion and alteration process is modeled using computer simulation and fluid composition and distribution of the resulting high-CO_2 reservoir is obtained after equilibration.The method is used to predict the fluid composition and spatial distribution of an oil reservoir with high-CO_2 content in deep water.The results are basically consistent with the reservoir fluid sampling results,which show that the method is feasible.

关 键 词：CO2 后期 充注 油气藏 流体性质 恢复 方法 

分 类 号：TE311[石油与天然气工程—油气田开发工程]