Process disturbances may cause reduction in production as the necessary margins to process constraints need to take peak values into account. If the process disturbances can be suppressed, it is possible to operate closer to constraints resulting in higher production.

For both injection and production wells, process disturbance rejection is typically achieved with automatic choke control, which is also beneficial for efficiently achieving changing target values. Good control requires accurate and up-to-date measurements. For cases where no reliable physical sensor is available, robust soft sensor design is a key element in the well control solution.

The process disturbances caused by natural fluctuations of the underlying process require frequent adjustments of the well chokes to maintain key parameters at their desired values. If wells are choked to ensure operation within given constraints, it is normally beneficial to implement automatic choke control since this enables operation closer to these constraints. The control target may also be to track a calculated downhole pressure trajectory during well restart. A smooth restart is important for some wells to avoid excessive sand production. In addition, automatic actions can be taken to reduce the risk of safety issues.

This paper presents field experience as perceived by a control engineer from applying automatic choke control to a large number of water injectors to stabilize the downhole injection pressure or injection rate and application of automatic control for production chokes to control downhole pressure. During restarts of production wells, the downhole pressure follows a pressure trajectory set point to minimize pressure fluctuations to avoid excessive sand production. Exchanging manual infrequent choke manipulations with automatic control to keep the process close to the true, physical constraints, enables safe and optimal production.

You can access this article if you purchase or spend a download.