Emulsification of Production Fluids in the Choke Valve

This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Abstract For oil production under high water cut conditions the efforts needed for de-oiling of the production water are mainly determined by the oil-droplet-size distribution of this water. This distribution is predominantly the result of droplet break-up in the choke valve. To determine the effect of the choke valve on the droplet-size distribution, we have conducted laboratory experiments in which we used a circular orifice in a circular pipe. With the help of theory on droplet break-up in turbulent flow and with knowledge of the flow field inside an orifice, a prediction of the distribution after break-up can be made. It is shown that the droplets increase in size with increasing oil viscosity and furthermore it appears that, for the description of the break-up process, the distribution of the turbulence over the orifice zone is an important factor. Introduction Often during the production of oil, water is produced as well. In these cases, the fluids enter the separator at the surface as an emulsion. At low water cuts the water will be dispersed in the oil, but at higher water cuts it will be the other way around. During the lifetime of a well the water cut is likely to increase, e.g. in the North Sea, wells producing at 95% water cut can be encountered. At high production rates, however, so-called tight emulsions-which are hard to separate-can be formed. There are cases where wells had to be shut in because the oil could not be separated from the water (Ref. 1). In …