Aspects of Oily Brine Clarification By The Use of Chemical Additives

The presence of small amounts of free or emulsified oil or oil coated solids in produced brines can adversely affect the properties of that brine in waterflooding and enhanced oil recovery projects. Likewise, the disposal of such oily brines can present a problem if the brine is being injected into a tight formation or, in the case of offshore platforms, if the brine is being disposed of overboard. Even if no difficulties are encountered in the reinjection or disposal of oily produced brines, the economic advantage of recovering even several hundred parts per million of residual oil from the brine should be considered. In many cases, the cost of the water clarification chemical required to recover the residual oil is small when compared to savings realized by recovering the oil. A large portion of the oil in oily produced brines is, in fact, emulsified into the water as a "reverse" emulsion. Such emulsions can be quite stable and require a long period of time to separate, due to stabilizing forces within the emulsion. Once recognized some of these forces can be neutralized by the addition of certain water soluble demulsifiers. A discussion of oily brine clarification, some theoretical considerations of emulsion technology, and a case history showing the economic advantage to residual oil recovery are included in this paper.