PVT气侵实验中链烷烃分馏效应及其地质意义  

Fractionation of chain alkanes and its geological significance in PVT gas invasion experiment

作　　者：李博偲 潘志强 何大祥[1] 唐友军[1] 李美俊[1,2] 王义凤[3,4] LI Bocai;PAN Zhiqiang;HE Daxiang;TANG Youjun;LI Meijun;WANG Yifeng(Hubei Key Laboratory of Petroleum Geochemistry and Environment,Yangtze University,Wuhan 430100,China;National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;Key Laboratory of Gas Reservoir Formation and Development,CNPC,Langfang 065007,China)

机构地区：[1]长江大学油气地球化学与环境湖北省重点实验室,湖北武汉430100 [2]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [3]中国石油天然气股份有限公司勘探开发研究院,北京100083 [4]中国石油天然气集团有限公司天然气成藏与开发重点实验室,河北廊坊065007

出　　处：《断块油气田》2025年第1期126-132,共7页Fault-Block Oil & Gas Field

基　　金：中国石油天然气股份有限公司前瞻性与基础性重大科技项目“大气田(区)成藏规律与勘探关键技术研究”(2021DJ0603)。

摘　　要：在实际地质过程中,气侵作用导致烃类流体分馏的变化主要与油藏PVT条件有关,随着实验体系和实验条件的固定化,从宏观上不能详尽展现某种系列化合物在PVT气侵实验中的分馏效应。为了厘定气、液两相中不同烃类的化学组成,文中开展横向、纵向实验期次的气侵实验,聚焦气侵作用对链烷烃的分馏效应,匹配地质背景和成藏过程,剖析不同强度气侵作用下链烷烃分子化合物组成变化规律。研究结果表明:随着气侵程度增强,不同烃类分子在气、液两相中分配系数发生变化,残余油轻组分不断降低,中、重组分分馏程度较小,呈现中—后峰形;凝析油轻组分不断增加,呈现前峰形。由于烃类组分分馏效应的影响,母质类型和沉积环境参数(Pr/Ph,Pr/nC_(17),Ph/nC_(18))出现变化。在具体地质应用中,链烷烃的分馏效应可以作为气侵作用的示踪指标运用在次生凝析气藏的形成模式中。研究结果有助于为深层油气相态的预测提供模拟实验的理论支撑。In the actual geological process,the fractionation change of hydrocarbon fluid caused by gas invasion is mainly related to the PVT condition of the reservoir.With the fixed experimental system and experimental conditions,the fractionation effect of a certain series of compounds in PVT gas invasion experiment cannot be demonstrated in detail from a macro perspective.In order to determine the chemical composition of different hydrocarbons in the gas and liquid phases,this paper carries out horizontal and vertical gas invasion experiments,focuses on the fractionation effect of gas invasion on alkanes,matches the geological background and accumulation process,and analyzes the composition changes of molecular compounds of alkanes under dfferent intensity gas invasion.The results show that with the increase of gas invasion degree,the distribution coefficients of different hydrocarbon molecules in the gas and liquid phases change,the light components of residual oil decrease continuously,and the fractionation degree of medium-heavy component is small,showing a middle-back peak shape.The light component of the condensate oil is increasing,showing a front peak shape.The parent material type and depositional environment parameters(Pr/Ph,Pr/nC_(17),Ph/nC_(18))change due to the fractionation effect of hydrocarbon components.Inspecificgeologicalapplications,the fractionation effect of chain alkanes can be used as a tracer index of gas invasion in the formation mode of secondary condensate gas reservoirs.The research results help to provide theoretical support for the prediction of deep oil and gas phases for simulation experiments.

关 键 词：PVT气侵实验 链烷烃 烃类流体 分馏效应 

分 类 号：TE122.31[石油与天然气工程—油气勘探]