Abstract
A new test method is presented for evaluating corrosion inhibitors for secondary recovery systems. The test is characterized by its relatively high ratio of volume of water to surface area of metal exposed.
Variables studied included dissolved oxygen, H2S, dissolved solids and pH. Corrosivity of a brine was found to be almost directly related to the dissolved oxygen level. It was found also that a high H2S system was not necessarily more corrosive than one having a low level of H2S, but that the attack became more localized. The higher the H2S level, the higher the inhibitor level required to obtain an equivalent level of protection. The greatest effects of variations in dissolved solids are indirect. The solubilities of dissolved gases and organic inhibitors are inversely proportional to the level of dissolved solids. The variation of pH in the range from 5 to 8 did not affect the performance of a typical inhibitor in a system without H2S. When H2S was present, the protection with this inhibitor dropped off slightly as the pH was lowered to 5.
This test method was used to evaluate a number of commercial water flood inhibitors. Experimental inhibitors were tested until one was found that exceeded the performance of those now being used. This one was tested in several floods and the excellent performance, predicted from the laboratory results, was confirmed. 5.8.1
