比例物理模型研究碱蒸汽驱提高稠油采收率

A SCALED MODEL STUDY OF CAUSTIC STEAM FLOODING

应用反五点井网三维高压相似比例物理模型,以NaOH溶液作为蒸汽驱的化学添加剂,进行了碱蒸汽驱提高稠油采收率及油汽比的实验研究。结果表明,在蒸汽驱中加入适量浓度的NaOH溶液,能够有效地扩大蒸汽在油层中的波及范围,降低油层下部的残余油饱和度和改善油汽比,提高原油采收率7％左右。碱浓度超过一定范围时,在油藏中出现了严重的堵塞现象,导致开采效果的降低。文中论述了产生这些现象的根本原因,并探讨了碱蒸汽驱的增产机理。

This paper presents a laboratory study of caustic steam flooding. The possibility of NaOH solution as chemical additive into steam to improve steam sweep efficiency and en- hanee oil recovery in the heavy oil reservoir has been evaluated. Experiments were conducted in a high pressure scaled physical model which was based on Pujol and Boberg's scaling ap- proach in a simulated 1/4th of a five-spot pattern. The results from the experiment indicate that the caustic steam flooding improved oil re- covery over conventional steam flooding by as much as 7%. The oil steam ratio was also im- proved. The tendency of steam overriding is reduced considerably. The study also show that caustic concentration seriously affect the oil recovery in caustic steam flooding, The charac- teristics of emulsion of oil-caustic system depends on the concentration of caustic solution and the emulsification is the principal mechanism of increasing oil recovery.