利用气相色谱指纹技术判识火驱燃烧状态--以杜66块为例

Using gas chromatographic fingerprint technique to identify combustion state during fire flooding:A case study of Du66 Block

为认清杜66块火驱开发过程中的地下燃烧状态,建立判识火驱燃烧状态的新方法,优选出3口生产井开展了长达5 a的原油及尾气的跟踪监测,利用原油气相色谱指纹技术与尾气多维气相色谱技术,研究生产现场火驱高温氧化的原油与尾气指纹特征参数。结果表明:火驱生产现场发生高温氧化后,原油正构烷烃色谱指纹呈现主峰碳前移、轻重比增加并伴随轻烃、异构烷烃、正构烷烃含量增加的特征;类异戊二烯烃色谱指纹特征表现为Ph/nC_(17)和Pr/nC_(18)值降低,iC_(21)与nC_(19)呈近水平或前低后高型分布;尾气中氧气转化率、视氢碳原子比、二氧化碳含量的综合运用是指示火驱高温氧化的有效参数,并且在尾气多维色谱指纹图中出现了烯烃、氢气等裂解组分。

To understand the underground combustion state during the fire flooding development of Du66 Block,we worked out a new method to identify the combustion state during fire flooding.Three production wells were selected to carry out the follow-up monitoring of crude oil and tail gas for five years.The gas chromatographic fingerprint technique of crude oil and the multi-dimensional gas chromatographic technique of tail gas were used to study the fingerprint characteristics and pa⁃rameters of crude oil and tail gas of high-temperature oxidation during fire flooding in the production field.The results show that the chromatographic fingerprint of n-alkanes of crude oil is featured by forward main peak carbon,higher light to-heavy ratio,increased content of light hydrocarbons,isoparaffins,and n-alkanes after high-temperature oxidation in the fire flooding production site.The chromatographic fingerprint of isoprenoid hydrocarbons shows reduced Ph/nC_(17) and Pr/nC_(18);the content of iC_(21) is nearly the same as or less than that of nC_(19).Oxygen conversion,apparent hydrogen-to-carbon atomic ratio,and carbon-dioxide content in tail gas are effective parameters for the high-temperature oxidation of fire flood⁃ing.In addition,cracked components such as olefins and hydrogen appear in the multi-dimensional chromatographic finger⁃print of tail gas.