Abstract

Maximizing oil recovery is a very challenging assignment to oilfield operators worldwide. This requires additional and continuous adoption of new technologies and best practices. Water flooding is one of the most reliable recovery technique and been used for many years around the world to pressure support to the reservoir and minimize the bypassed oil in depleted reservoirs with no aquifer support.

This paper is presenting a case of well that was drilled and completed as a dumpflood well to provide pressure support to an oil-bearing zone that contributes most of the field's production. Dumping rates have showed poor performance due to near wellbore damage since completion. Many conventional stimulation trials were carried out with no sustained success. The well was selected for an advanced acid stimulation technique to improve the dumping rate by using the concept of Oscillating Fluid Injection. This process achieves deeper treatment penetration and more uniform fluid distribution. Root cause analysis, core analysis and well history have been used to optimize the job procedures and acid recipe to remove the suspected damage. The above-mentioned process treated the target zone with the same acid recipe that has been used in the previous conventional acid stimulation job.

The results of this advanced process showed a significant improvement in well injectivity compared with previous acid stimulation techniques. The post treatment evaluation showed an increased dumping rate by two times. The increased flowing bottomhole pressures observed in the surrounding producing wells confirm the direct benefit of the improved injectivity and consequent pressure support. These promising indications have opened new production optimization opportunities in the nearby wells to add significant oil gain.

This paper presents an unconventional method of acid stimulation technology in the improvement of injectivity in surface injection and dumpflood injectors compared with conventional techniques. This technology has opened new opportunities for improving the injectivity of the dumpflood wells, and go for full field implementation to maximize the oil recovery from depleted reservoir.

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