渤海 Ｋ油田空气驱对原油低温氧化影响研究

以渤海K油田为研究对象，利用氧化实验仪，模拟油藏温度(110℃)和压力(24MPa)，系统研究了不 同氧含量(3%~12%)减氧空气对该油田原油的氧化可行性；并利用气相及液相色谱仪检测减氧空气及原油氧化 前、后组份构成与含量。实验结果表明，实验前、后原油和减氧空气组份含量明显不同，如原油中较高烃组成(≥ C14)含量下降、较低烃组成(C8~C10)含量增加；减氧空气中氧含量下降、二氧化碳有定量(<0.6%)增加；说明K油田原油在油藏温度压力下可与减氧空气发生低温氧化反应。反应过程中，原油以氧化降解为主，完全氧化生成 二氧化碳为辅；该氧化反应进行程度随减氧空气中含氧量增加而增大，表现为对应氧耗量增大、原油被氧化的“临 界碳数”下降(由 C22下降至 C14)、二氧化碳含量由 0.075%增加至 0.6%。实验减氧空气与K油田原油氧化 120 h后残余氧含量均低于 10%，表明渤海Ｋ油田实施减氧空气驱具有良好的安全可行性。

INFLUENCE OF AIR DRIVE ON LOW TEMPERATURE OXIDATION OF CRUDE OIL IN K OILFIELD AT BOHAI

Taking the Bohai K oilfield as the research object, the feasibility of oxidation of crude oil with different oxygen content( 3 ~ 12% ) air was systematically studied by using the oxidation experiment instrument and the reservoir temperature of 110℃ and pressure of 24 MPa simulated. The composition and content of oxygen-reduced air and components before and after oxidation of crude oil were detected by means of gas phase and liquid chromatography. The experimental results showed that component contents of the crude oil and oxygen-reduced air before and after the experiment was significantly different. The content of higher hydrocarbon composition (≥C14) in crude oil decreased, the content of lower hydrocarbon composition ( C8 ~C10) increased, and the oxygen content in oxygen-reduced air decreased, the amount of carbon dioxide increased (< 0. 6% ) simultaneously, indicating that crude oil at K oilfield could conduct a low temperature oxidation with oxygen-reduced air at reservoir temperature and pressure. During the reaction, the crude oil was mainly oxidized and degraded, and the complete oxidation to form carbon dioxide was the supplementary reaction. The oxidation degree was increased with the increase of oxygen content in the oxygen-reduced air, which was manifested by an increase in the oxygen consumption, a decrease in the “critical carbon number” of the crude oil being oxidized (from C22 to C14) , and the carbon dioxide content increased from 0. 075% to 0. 6% . The residual oxygen content after oxygen-reduced air reacted with K-field crude oil for 120 hours was all less than 10% , which means that the oxygen-reduced air flooding at Bohai K oilfield can be safely and well performed.