Generation of Curves of Effective Gas Separation at the ESP Intake on the Basis of Processed Real Measurements Collected in the Priobskoye Oil Field

Abstract

Well performance monitoring is extremely useful to effectively control hydrocarbon production and make timely decisions when it comes to run various well interventions. The more ample and correct are the data at our disposal, the more efficient will be the management. Traditionally little attention is given to the gas liberated at oil degassing and no measurements are taken; although this kind of data would allow computing a number of rather critical figures, such as gas content in the mixture, bottomhole pressure, etc. For the moment maximum 20% of all the wells in the Priobskoye field are outfitted with the PHD sensors, and the BHP as well as the pressure at the ESP intake for the most of the wells are computed. This kind of computation requires an ESP separation efficiency function. However, all the available efficiency-function computation equations are based on tests run on recombined liquid/gas mixtures at lab setups, that is, under ideal conditions. In this paper we put focus on the efforts to evaluate the free gas separation at the ESP intake; estimate the bottomhole pressure based on production data; and assess the gas separation impact on both the pumping unit performance (variation of Q-H characteristics) and the in the tubing and annulus flow parameters. Measurements of the dynamic level and wellhead annulus pressure that vary with time and allow computation of the fraction of the gas separated were used as input data. As well as the data collected with the PHD sensors, or pressure gauges below the ESP.