Abstract
As a general practice water is injected along the O/W contact to maintain reservoir pressure during production. Down hole analysis of the injected water shows that, even after surface treatment, it still can contain a considerable amount of solid particles. These particles can bridge formation pores and cause a considerable reduction in the injectivity. To ensure good injectivity over a longer term, the concentration and size of these solids should not exceed certain limits. These limits can be determined by performing core flood tests and evaluating the damaging effect of different solid particles. To correctly simulate near well bore formation damage, the lab core injection conditions and the injected water quality must be as close as possible to the actual field injection process conditions.
In this article core flood tests were carried out to simulate high rate injectors. The injected brine contained solid particles in different concentrations and sizes. Particle concentration was between 5 and 20 ppm and the particle mean size was between 2 and 9 mu m.
The results were presented as damaging ratio versus pore volume injected. Contrarily to previous studies instead of using experimental results in calibrating or evaluating certain theoretical models, the results in this study were directly fitted to produce equations which can predict the extent of damage caused by injected water by knowing the mean size and concentration of the solid particles contained in that water.