Dynamic multiphase flow behavior inside a mixed flow electrical submersible pump (ESP) has been studied experimentally and theoretically for the flrst time. The overall objectives of this study are to determine the flow patterns and bubble behavior inside the ESP and to predict the operational conditions that cause surging. An experimental facility has been designed and constructed to enable flow pattern visualization inside the second stage of a real ESP. Special high-speed instrumentation was .^elected to acquire visual flow dynamics and bubble size measurements inside the impeller channel. Experimental data were acquired utilizing two types of tests (surging test and bubble diameter measurement test) to completely evaluate the pump behavior at dijferetu operatiotial conditions. A similarity analysis performed for single-phase flow inside the pump concluded that viscosity effects are negligible compared to the centrifugal field effects for rotational speeds higher than 600 rpm. Therefore, the two-phase flow tests were peiformed for a rotational speeds ofóOO. 900, 1200, and 1500 rpm. Results showed formation of a large gas pocket at the pump intake during surging conditions.

Dynamic multiphase flow behavior inside a mixed flow Electrical Submersible Pump (ESP) has been studied experimentally and theoretically for the first time. The overall objectives of this study are to determine the flow patterns and bubble behavior inside the ESP and to predict the operational conditions that cause surging. The theoretical study includes a mechanistic model for the prediction of the flow behavior inside the pump. The model comprises a one-dimensional force balance to predict occurrence of the stagnant bubbles at the channel intake. This model depends on two important variables, namely the stagnant bubble size and the bubble drag coefficient. The bubble size has been measured and a physically based correlation is presented. A new correlation for the drag coefficient is proposed as a function of rotational speed and Reynolds number. The model enables the prediction of the operational envelope of the ESP, namely the transition to surging.

Dynamic multiphase flow behavior inside a mixed flow Electrical Submersible Pump (ESP) has been studied experimentally and theoretically for the first time. The overall objectives of this study are to determine the flow patterns and bubble behavior inside the ESP and to predict the operational conditions that cause surging. An experimental facility has been designed and constructed to enable flow pattern visualization inside the second stage of a real ESP. Special high speed instrumentation was selected to acquire visual flow dynamics and bubble size measurements inside the impeller channel. Experimental data was acquired utilizing two types of tests (surging test and bubble diameter measurement test) to completely evaluate the pump behavior at different operational conditions. A similarity analysis performed for single-phase flow inside the pump concluded that viscosity effects are negligible compared to the centrifugal field effects for rotational speeds higher than 600 rpm. Therefore, the two-phase flow tests were performed for rotational speeds of 600, 900, 1200, and 1500 rpm. Results showed formation of a large gas pocket at the pump intake during surging conditions.

This paper provides insight into the Caisson ESP Technology Maturation for subsea boosting systems with high GOR and viscous fluids. It will focus on the developmental research on the effects of viscosity and two phase (liquid & gas) fluids on electric submersible pumps (ESPs), which are multistage centrifugal pumps for deep boreholes. The Electrical Submersible Pump (ESP) system is an important artificial lift method commonly used for subsea boosting systems. Multiphase flow and viscous fluids cause problems in pump applications. Free gas inside an ESP causes many operational problems such as loss of pump performance or gas lock conditions (Barrios 2010 [6]). The objective of this study is to predict the operational conditions that cause degradation and gas lock. This paper provides a summary on the Technology maturation for a high scale ESP Multi-Vane Pump (MVP) for high GOR fields to in support of Shell's BC-10 developments. These novel projects continue the long tradition of Shell's leadership in the challenging deepwater environment. This paper will describe the capability and effects of viscosity and two phase (liquid & gas) fluids using a MVP 875 series G470 as a charged pump in a standard ESP system 1025 series tandem WJE 1000 mixed-type pump. Extensive testing and qualification of the subsea boosting system was undertaken prior to field considerations. Testing was conducted at the world's only 1500-hp ESP test facility capable of controlling multi-phase fluid viscosities and temperatures. A comprehensive suite of tests was performed in conjunction with Baker Hughes Centrilift replicating the expected conditions and performance requirements for Shell's deepwater assets. This paper describes the subsea boosting system maturity process, and reports the effects of viscosity and two phase liquid - gas fluids on ESPs. The test facility work was performed using pumps with ten or more stages moving fluids with viscosity from 2 to 400 cP at various speed, intake pressure, and gas void fractions (GVF, aka gas volume fractions). The testing at Shell's Gasmer facility revealed that the MVP-ESP system is robust and performance tracked theoretical predictions over a wide range of two-phase flow rates and light-viscosity oils

This paper provides field experience for the Caisson ESP Technology in subsea boosting system with emulsions and high Gas Volumen Fraction (GVF) using the high power Electric Submersible Pumps (ESPs) systems. Field experience and experimental performance are compared regarding the effects of high viscous emulsion using conventional high capacity ESP systems and the effect of two phase (liquid & gas) fluids on ESP with new technology for high GVF fields and high viscous applications. The Electrical Submersible Pump (ESP) system is an important artificial lift method commonly used for subsea boosting systems. Multiphase flow and viscous fluids cause problems in pump applications. Free gas inside an ESP causes many operational problems such as loss of pump performance or gas lock condition. The objective of this paper is to understand MVP performance for high GVF and viscous emulsions. This paper provides a summary on the performance comparison for a high power ESP system for viscous emulsions and Multi-Vane Pump (MVP) for high GVF wells for Shell major Projects BC-10. These novel projects continue the long tradition of Shell’s leadership in the challenging deepwater environment. Presented is the capability and effects of viscosity and two phase (liquid & gas) fluids using a 1025 series pumps with a charge MVP in series; as well as a 875 series standard ESP system mixed-type pump, which is a multistage centrifugal pumps for deep boreholes. Extensive testing and qualification of the subsea boosting system was undertaken prior to field application. The subsea boosting system experience for offshore operations is reported with new technology, and the effects of viscosity and two phases in real conditions. MVP and high power pumps were proved to be a reliable technology to use in field application managing GVF higher than 50% and high viscous fluid as high as 1200cp as consequence of fluid emulsion. Correction factors needed to be applied to standard design curves to ensure proper field design at opearting conditions.