Gary H. Jacobs, Amoco Production Company
The purpose of a gas separator is to separate free gas from produced fluid before the fluid enters the intake of an electric submersible pump (ESP). If free gas is allowed to enter the ESP, it tends to cause the ESP to cycle, resulting in additional pump and motor wear and eventual contamination of the motor oil with wellbore fluids. Two types of gas separators are commonly available, the reverse flow separator and the rotary separator. This paper summarizes a recent field test in which the performance of the rotary gas separator was compared to that of a reverse flow separator under similar conditions in the same well. This field test was done on a low volume well under waterflood. An ESP was run in this well because a beam lift would interfere with the landowner's irrigation equipment. The original ESP, which was run with a standard reverse flow separator, could not pump the fluid level down because excessive gas caused the unit to cycle on and off. Three cases were studied. The first two cases consisted of running two identical 400 BPD ESPs, each one for a period of several months. The first ESP was equipped with a standard reverse flow separator and the second was equipped with a rotary gas separator. In the third case, a 280 BPD ESP equipped with a rotary gas separator was studied. It was necessary to run this ESP because the originally sized 400 BPD ESP became oversized once the effect of gas cycling was removed due to the rotary gas separator.