An exciting case study featuring oil well injection in the Bakken Basin of North Dakota was published in the June 2020 issue of Flow Control Magazine. Co-authored by Diane Jacober of Equilibar and Christopher Duffield of Intermountain Electronics, the article explains how direct-sealing diaphragm valves offer practical advantages for difficult flow control applications, especially those requiring a wide Cv range, superior precision and multi-phase fluid control.
Intermountain Electronics provides custom engineered solutions for upstream and midstream petroleum industry projects. The company was retained to design a multi-well automated water injection system to inject water at the base of oil wells to prevent salt from crystallizing inside the wellhead, which can lead to maintenance and down-time issues.
Careful dosing was important because the application required having just enough water to prevent crystallization. Water in excess of the minimum requirements would increase the volume needing to be treated, transported or re-injected into the ground via saltwater disposal wells.
In addition, oil well pressure is extremely variable and the flow requirements vary significantly from well to well. Required water injection flow rates varied through a 50:1 range. Available pressure drop varied through a 22:1 range. The resulting valve coefficient needed ranged through a 230:1 ratio, exceeding typical control valve capabilities.
To find the best solution to this difficult scenario, Intermountain Electronics consulted with Equilibar engineers. While Equilibar® direct-sealing diaphragm valves have been used to handle especially difficult pressure control applications for more than a decade, they have only recently been adopted for flow control applications. This type of valve uses multiple orifices and pneumatic pilot pressure set point on top of the diaphragm to create precise control across a wide range of flow. An electronic pilot pressure controller communicates with a proportional-integral-derivative controller to deliver the appropriate pneumatic set point to the diaphragm valve.
For more details on this successful approach to flow control, including schematics for how to configure the direct-sealing diaphragm valve, read the article on Flow Control Network.
To learn more about Equilibar’s fluid control products, contact one of our engineers. They are happy to learn about your challenge.