Chemelectric Treating A New Phase In The Electrical Dehydration Of Oil Emulsions

Abstract

SUMMARY Chemelectric Treating is a method of treating oil field emulsions which combines the principles of electrical dehydration with the most advanced variations of the thermo-chemical method of treatment. Actually, this is the second phase of application of such a combination to the treatment of oil field emulsions, the first one occurring thirty or more years ago. Re-introduction of the method in oil field treating applications was prompted by three sets of circumstances. First, under conditions now existing certain inherent characteristics of electrical dehydration offer distinct advantages. This would include:Ability to treat at relatively low temperatures with resulting savings in fuel and possibility of improvement of quality and quantity of stock tank oil.High adaptability to unattended operation and remote supervisory control.High treating capacity which makes the method applicable in consolidated tank batteries. Second, the thermo-chemical portion of the apparatus employes highly efficient design developed only a few years ago. Third, the present high degree of oil field electrification makes the method applicable in a predominant majority of treating installations. The method offers an important addition to the practice of treating oil field emulsions. Under certain conditions, discussed in the paper, its use may be of distinctive economic advantage. THE PAST AND THE PRESENT . . . RELATED: The problem of separating water from produced crude oil is as old as the Oil industry itself. In the early days of the Industry the problem was handled by settling the free water from oil in open tanks or pits. The intermediate phase between clean water and clean oil, referred to as "sludge," was disposed of usually by burning. It was not until the turn of the century that attention was called to the fact that "sludge" is an emulsion of crude oil and water and that substantial amounts of merchantable oil can be recovered from this emulsion. The establishment of this fact was followed by a long period of developing different methods and equipment needed to treat crude oil sludges or emulsions. One of these methods, was electric dehydration. It was first developed and applied in the 1910's in California. During the 1920's the use of the method spread to other oil producing parts of the country, particularly to the oil fields of the Texas-Louisiana Gulf Coast. Introduction, in the early 1930's of the highly efficient, unitized, pressure-operated heater-treater furnished oil operators with emulsion-treating equipment with which the electrical dehydration could not economically compete under conditions then existing. For all practical purposes electrical dehydrators disappeared from the oil producing leases east of the Rocky Mountains in the late 1930's. In the meantime, electrical dehydration found a wide application in crude oil desalting and other operations within oil refineries. The method of electrical dehydration has now been re-introduced as a technique of oil field emulsion treating. It is referred to as Chemelectric Treating. The reasons to be discussed later, which justify the revival of the method as far as oil production is concerned include improved equipment, the new manner in which the process is offered to the Industry, and the changed field conditions, as compared to those which existed thirty or more years ago. In this the second phase of its oil field application, electrical dehydration is not here to replace present methods of emulsion treating, but rather to supplement them in cases in which it can offer an economic advantage. P. 1^