高含CO_(2)凝析气藏成藏过程中的流体相行为及油环体积预测  

Fluid Phase Behavior and Oil Ring Volume Prediction During Formation of High CO_(2)Condensate Gas Reservoirs

作　　者：陈浩[1,2] 左名圣 王红平 王朝锋 徐程浩 杨柳 刘希良 袁志文 Chen Hao;Zuo Mingsheng;Wang Hongping;Wang Chaofeng;Xu Chenghao;Yang Liu;Liu Xiliang;Yuan Zhiwen(College of Safety and Ocean Engineering,China University of Petroleum(Beijing),Beijing 102249,China;State Key Laboratory of Petroleum Resources and Prospecting(China University of Petroleum(Beijing)),Beijing 102249,China;Petroleum China Hangzhou Research Institute of Geology,Hangzhou 310023,China)

机构地区：[1]中国石油大学(北京)安全与海洋工程学院,北京102249 [2]油气资源与探测国家重点实验室(中国石油大学(北京)),北京102249 [3]中国石油杭州地质研究院,杭州310023

出　　处：《吉林大学学报（地球科学版）》2024年第5期1506-1518,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(52274053);北京市自然科学基金项目(3232028)。

摘　　要：成藏后期的CO_(2)充注导致里贝拉区块高含CO_(2)次生凝析气藏的流体相行为十分复杂,油环体积预测难度很大。本文通过流体相平衡模拟、组分梯度分布计算及CO_(2)充注可视化实验,刻画了CO_(2)充注过程中的油气相行为,揭示了油环体积的动态变化规律,建立了基于气顶气组分拟合的高含CO_(2)次生凝析气藏油环体积预测新方法。研究结果表明:1)CO_(2)充注下的油环体积变化分为4个阶段:充注初期,油环以溶胀为主;充注前期,CO_(2)不断置换并萃取油相中的轻质组分,油环体积迅速降低;充注中期,CO_(2)持续萃取油相的轻、中质组分,油环体积缓慢减小;充注后期,CO_(2)-原油组分传质作用明显减弱,压缩效应导致油环体积进一步减小。2)轻质组分的强流动性使气顶气组成均一,重力分异作用使纵向上油环组分呈梯度变化。3)油环体积与气顶气组成和气油比密切相关。4)基于气顶气拟合新方法和不同井深现场勘探预测的油环体积占比分别为19.21%和22.30%,与CO_(2)充注可视化实验获得的油环体积占比(20.60%)较为吻合。For the high CO_(2)condensate gas reservoir in Libra block,the fluid phase behavior in the reservoir is very complex due to the injection of CO_(2)in the later stage of reservoir formation,which brings great challenges to the prediction of oil ring volume.Through phase equilibrium calculation model,component gradient distribution theory,and visual injection experiment,this paper describes the oil-gas phase behavior of the reservoir during CO_(2)injection,reveals the dynamic change of oil ring volume,and puts forward a new method for predicting oil ring volume of secondary condensate gas reservoir with high CO_(2)based on gas cap gas component fitting.The following research results are obtained.1)The fluid phase behavior and volume change of oil ring under CO_(2)injection can be divided into four stages.At the beginning of CO_(2)injection,CO_(2)dissolves in the oil and the volume of oil ring expands.In the early stage,CO_(2)dissolves,replaces and extracts the light components in the oil,so that the volume of the oil ring decreases rapidly.In the middle stage,CO_(2)mainly extracts the light and medium components of oil,so the volume of the oil ring decreases slowly.At the later stage,the mass transfer of CO_(2)-oil almost stops,so the proportion of oil ring volume further decreases due to the compression effect.2)The strong fluidity of light components makes the gas composition of gas cap uniform,and the gravity differentiation makes the oil ring composition gradient change longitudinally.3)On this basis,the strong correlation between gas cap gas composition,gas-oil ratio and oil ring volume are revealed.4)The oil ring volumes ratio predicted by the new gas cap gas fitting method and field exploration at different well depths are 19.21%and 22.30%,respectively,which are in good agreement with the oil ring volume ratio(20.60%)obtained from the CO_(2)injecting visualization experiment.

关 键 词：气藏 CO_(2)-原油组分传质 流体相行为 油环体积预测 组分梯度分布 可视化实验 

分 类 号：TE19[石油与天然气工程—油气勘探]