In many service applications excursions in solution chemistry, temporary loss of inhibitor, or transient increases in temperature may give rise to localised corrosion. To test the return of inhibition when the loss is remedied, the use of an artificial pit has been investigated using simulations of cooling water and of of oil production formation water.
A forty foot well annulus simulator is used to determine the flow and fate of the applied chemical inhibitors for typical backside batch and flush application in a packerless completion. The delivery depends upon both chemical parameters such as density, viscosity, and surface tension as well as flush parameters including volume and rate.
A novel evaluation technique, based on an artificial pit electrode, has been developed for inhibitor studies. The first example is of three generic inhibitors, against localised corrosion. The second is of three industrial inhibitors against existing localised corrosion on a north sea production platform