Competitive System Concepts for Electrification of Subsea Structures in Co-Existence with Electro-Hydraulic Control Systems

Abstract

Abstract Objectives/Scope Subsea production systems can benefit today from the application of partial electrification concepts in hybrid scenarios coexisting with electro-hydraulic (E/H) control systems. This paper is based on a real project that included a system of conventional E/H subsea production trees, manifolds, and a boosting station, together with a subsea distribution and control system. Based on this architecture, an alternative field concept optimized for partial electric actuation resulted in very competitive commercial scenarios in addition to operational benefits and increased sustainability. Methods, Procedures, Process Using electric actuators for valves on subsea production system structures is becoming more common but is still limited. The reason for this limitation is that the systems are often not fully optimized for these uses. There are operational and conceptual differences between traditional electro-hydraulic systems and electric actuation systems. For many years subsea engineers have applied proven field and system concepts and established work practices to field development and subsea control scenarios, which might not have been successful if applied to electric actuation without further change. Electric actuators cannot replace hydraulic actuators without also rethinking the underlying system architecture. Results, Observations, Conclusions When alternative configurations were analyzed, the basic architecture was maintained. But instead of simply replacing the hydraulic actuator with electric actuators, it was important to consider how the actuators were connected to the control system in terms of distance, communication, and overall layout. Holistic optimization of the subsea distribution and control system introduces significant benefits to the whole system. However, electric actuators have different performance and diagnostics characteristics than hydraulic actuation systems. Specific sessions were held with the operator, focusing on system performance and the operational advantages of the proposed system. The subsea distribution system and its control philosophy were changed from a traditional layout to a layout taking full advantage of the benefits electric actuators are offering. This paper uses before-and-after comparisons to show how moving from traditional subsea control methods to a "hybrid" system enables a more sustainable architecture by combining "traditional" products with newer electric actuation methods. As a result of those benefits, the end user in this case study selected the hybrid system and replaced the original base case.