The Peregrino field is located in Campos Basin approximately 85 km offshore from Cabo Frio in Brazil. The oil in Peregrino is heavy with a gravity of 14° API. First phase of field development will be accomplished by two drilling capable wellhead platforms tied back to a central FPSO. A Total of 30 producer and 7 water injector wells are planned for this phase.One of the most critical factors in offshore operations is physical space. Flow allocation devices like test separators can be bulky due to the large capacities required to operate with heavy oil. These and the gear required for their control and efficient operation like heaters can be among the most space consuming equipment onboard. Multiphase flow meters are also available for flow allocation purposes; however its accuracy is highly impacted by heavy oils. The slow gas flashing out of heavy oils affects the representativeness of necessary pressure-volume-temperature (PVT) characterization.Downhole Venturi meters were other alternative considered when deciding about the flow allocation method for Peregrino. These were initially left behind basically due to two factors; the economical impact related with a single unit required per well and the limited data available regarding its uncertainty with viscous oil. The changing oil/water conditions in Peregrino can be a challenge from a viscosity modeling point of view. Therefore a decision was made in favor of the flow allocation based in Electric Submersible Pumps (ESPs) performance. This technique has been used with success in wells with very high water cuts but it's a novel approach in viscous oil.Improving the accuracy of this approach required multiple tests with the submersible pump models selected for Peregrino field. The tests were performed in a high viscosity flow loop in Claremore and covered a wide range of viscosities and speeds. This paper outlines the test results and presents the principles of flow allocation in Peregrino.

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An Integrated Solution Enabling Allocation of Heavy Oil in the Peregrino FieldUnconventional oil plays a growing role in the petroleum industry, especially in operational regions such as Latin America, China and Canada. The complexity of producing from a heavy oil reservoir is a challenge not limited only by 'economics' but also by the available technology. There are various methods of producing from heavy oil reservoirs ranging from open-pit mining to steam assisted production. In areas such as Latin America, cold production is used where electrical submersible pumps (ESPs) are employed to artificially lift the oil from the reservoir. This paper highlights an integrated approach of using ESPs and downhole flowmeters in heavy oil production. It will focus on the validation and analysis of the allocation performance of the downhole flowmeters used in the Peregrino field, Brazil. Peregrino is located offshore of Brazil and the ESPs and flowmeters will be used for the multiple wells in the field. There are huge variations in the well's behavior such as production rates as well as bottomhole pressure.Before field deployment, a test was commissioned to benchmark the performance of the ESPs and flowmeter when working in tandem. Different sizes of flowmeters were tested over the flow range of 500stb/d and 30,000stb/d and up to 360cP in oil viscosity. New correction methods were employed to improve the measurement accuracies such as an iterative calculation of the flowmeter discharge coefficient based on the measured fluid properties. The results from this test will help to validate the performance of the ESP while the flowmeter allocation accuracies can be verified to meet the Brazilian authority (Agencia Nacional de Petroleo -ANP) specification. The lessons learned will be applied towards future field allocation applications using downhole flowmeters in the Peregrino field.

An Integrated Solution Enabling Allocation of Heavy Oil in the Peregrino Field The complexity of producing from a heavy oil reservoir is a challenge limited by both economics and available technology. Various methods exist for producing from heavy oil reservoirs, but in areas such as Latin America, cold production is used where electrical submersible pumps (ESPs) are employed to artificially lift the oil from the reservoir. This paper highlights an integrated approach of using ESPs and downhole flowmeters in heavy oil production. It will focus on the validation and analysis of production performance from ESPs and the allocation performance of the downhole flowmeters used in multiple wells in Peregrino field, offshore Brazil to address huge variations in the wells’ behavior such as production rates and bottomhole pressure. A test was commissioned to benchmark ESP and flowmeter functions when working in tandem. Three sizes of ESPs and flowmeters were tested over the flow range of 500stb/d and 22,000stb/d and up to 360cP in oil viscosity. The ESPs were operated from 2300 to 3600 rpm in the different viscosity fluids and used water data as a baseline to calculate the performance correction factors for each operating condition. The performance correction factor is incorporated into the development of software to predict the performance of each pump at a specific operating condition. Eventually, the data will be used to develop the ESPs’ monitoring tool. In the downhole flowmeter test, new correction methods were employed to improve the measurement accuracies such as an iterative calculation of the discharge coefficient based on the measured fluid properties. Test results will help validate ESP performance and verify flowmeter allocation accuracies to meet ANP specifications. The lessons learned will be applied toward future field allocation application using downhole flowmeters in the Peregrino field.