Abstract
An electric choke can be an essential component of a subsea system and could represent the next major leap in subsea innovation. This paper presents the added functionality that an electric choke can bring to a subsea system during production startups and shutdowns as well as how it can improve condition monitoring and downhole instrumentation protection.
The electric choke can be easily integrated to a hydraulic or electric control system. It is driven by a motor and does not require stepping, therefore enabling greater control and precision. A comparison is presented between typical operations of a field using a traditional hydraulic choke versus an electric choke. We will also look at some of the additional benefits an infinite number of positions can bring to the system for production and injection field operations.
Electrically actuated chokes provide several advantages during production startup and shutdown. An unlimited number of precise positionings means that wells can be brought onstream and shut down gradually to prevent formation damage.
For monitoring purposes, there is an improved response time in diagnostics and interpretation of measurements coming from the downhole valves, sensors, wellhead, and subsea instrumentation. This improved response and additional information, including actuator motor power consumption, actuator motor speed, and valve and choke position, enable better condition monitoring, and through predictive analytics, uptime can be optimized and interventions can be reduced.
In long-offset fields, electrically actuated chokes provide protection of downhole equipment, such as surface-controlled subsea safety valves (SCSSVs) and downhole screens. Electric subsea production control systems have been around since the late 1990s. Because of the recent economic climate, the industry is now looking for more effective ways to produce hydrocarbons, and removing hydraulics from the system seems to be a cost-effective and technically feasible solution. Electrically actuating chokes provides great benefits and opens the door for fully electric systems in the future.
