Get Inline: Continuous, Instant, Concurrent Three-Phase Separation
Authors: Comert Secil , Khan Rafiqul , King Chris , Kuan Pearl , Hamed Nejib , Brown Eugene 
Published: November 2019

Effective water management of produced water from oil and gas production is a crucial part of the overall hydrocarbon production management, especially in many areas around the world where water-to-oil ratios surpass 10 to 1. Consequently, the industry requires robust water treatment processes that can handle feed variations over extended periods without derailing hydrocarbon production. Flexible technology modules and their systematic process combination are necessary to provide solutions not just for varying conditions, but also for various applications.

Traditional treatment approaches involve numerous tanks, vessels, separators, and associated equipment for separation of each constituent from produced water. This requires not only a large footprint but also high capital investment and operating costs. To deliver new efficiencies to oilfield water sourcing and management, a high-throughput, three-phase, inline separator has been introduced to provide continuous, instantaneous, and concurrent separation of water, oil, and solids at high flow rates.

A thorough evaluation of new technology enables the industry to minimize deployment risk and quickly realize its benefits. This study covers an extensive test matrix, executed to map the performance of the inline three-phase separator. Its fundamental physical principle is the generation of significant gravitational force by an impeller-induced vortex and the consequential separation of three-phase mixtures of water, oil, and solids based on density difference. The heavier elements are drawn to the outside of the vortex while the lighter materials are drawn toward the center, forming a central core of the vortex. A specially designed manifold at the exit of the separation chamber collects the separated streams. Because the underlying process is a function of equipment geometry, impeller rotational speed, and feed flow rate and composition, parameters were systematically changed in a pilot set-up to test at flow rates up to 100 gallons per minute (galUS/min). A comprehensive computational fluid dynamics (CFD) study complemented the physical testing to develop and validate a separation model for sizing parameters and performance prediction purposes. The combined results show a wide operating window for the inline separator with no pressure drop across, achieving simultaneously effective bulk separation of oil for immediate value-add, removal of damaging solids from the process, and water at qualities for use or further treatment depending on the end application.

Although performance evaluation of new technology is at the heart of product development, usability; health, safety, and environmental aspects; and process integration takes no minor part in this process and is crucial for successful deployment. The inline three-phase separator has been deployed in two different versions and three sizes to enable skid mobilization and trailer-mounted deployment. Consequently, the inline separator provides solutions—alone or in combination—such as debottlenecking current water treatment facilities and mobile deployment for remote and temporary installations and provides an effective, small-footprint bulk separator for currently planned facilities.