The steam stimulation is a main method to develop the heavy oil reservoir. However, the huff-puff wells will be water-flooded quickly if the reservoir has edge water, and the oil production level will decrease sharply. An experimental device, which can simulate edge water and steam stimulation process, was designed according to the feature of Henan heavy oil reservoir with edge water on the basis of steam flooding device, and the effect factors and application conditions of nitrogen foam anti-edge water-incursion technology were researched. The results show that the anti-edge water-incursion technology is suitable for the heavy oil reservoir with a medium energy edge water, and a better foam plugging will be got if the technology is applied at the time of serious water-flooded. The optimum injection pattern of the technology is a N2 slug first, followed by a nitrogen foam slug, and then the steam slug. Field tests were proceeded on the basis of experiment results and field experience, the operation success rate is 100%, the average drainage period reduces by 0.7d, the average cycle water cut reduces by 23%, the average cycle oil production increases by 2 times, and the average single-well oil-steam ratio increases by 0.25. So the technology can reduce water cut and increase oil production significantly, and the target of edge water inhibition is achieved.
Status Quo of a CO2-Assisted Steam-Flooding Pilot Test in China
