Electro-Hydraulic Servo Actuation for Well Completions

Abstract

Well Completions are challenged with the demands of managing increased multiple production zones. This paper addresses a solution to these issues: Reduce the number of hydraulic control lines. Provide independent production zone flow control. Support a multiplicity of hydraulic actuated devices. These Well Completion challenges are addressed using networked Electro-hydraulic Servo Actuators (EHSA). The EHSA is a small diameter, closed loop, hydrostatically balanced electro-hydraulic actuation system. EHSA has a feature set to support intelligent and autonomous multizone Well Completions. Each EHSA servo provides controlled operation of a device at a remote endpoint downhole. Bidirectional flow is obtained directly from the rotation of the pump and motor, eliminating the use of check, relief, and solenoid valving. Measured flow and pressure provide incremental precision positioning. Multiple hydraulic control lines are eliminated. Years of extensive testing programs validated reliable and consistent operations verified in hydrostatic autoclave stress test equipment. EHSA tests demonstrate years of operation, estimated to meet or exceed 20 years of operation. The system operates with electrical wires providing direct command/response capability and power. A single TEC line can support a multiple EHSA network. Alternately, pressure pulse commands can be transmitted from the surface to control each battery powered EHSA. Autonomous control in response to sensor inputs allows for adjustment of the well control devices, for instance in response to well pressure changes. A real-time clock provides for a predetermined schedule of operations, possibly combined with command/response, autonomous control, and sensor measurements. Self-balancing eliminates hydraulic lock by uniquely adding or disposing of fluid imbalance with the hydraulic reservoir. The positive displacement operation is calibratable and proven highly repeatable. Remedial override is inherent in the EHSA because there are no valves. The EHSA is a multiple-use hydraulic engine with intelligent control features for various types of completion devices either single-use or permanent installation.