Abstract
Intelligent completions are expected to play a growing role in all future major subsea fields, giving the capability to maximize hydrocarbon recovery while reducing production costs and number of interventions. In the present mature "pressure monitoring" market, single-point pressure sensors are traditionally acquired by third-party subsea control pods. There is no dedicated software associated with the tool at topside for any computation more complicated than applying polynomial equations. The communication protocols over umbilicals are generally proprietary to each pod vendor, which requires a new interface card for each application, increasing risks and lead time by months, and affecting system reliability by lack of repetitiveness. Intelligent completions require typically 10 times more communication bandwidth than currently available, 10 to 100 times more power than pressure gauges, dedicated software processes at topside, and increased reliability of the interface links. Traditional practices need to be revisited for accommodating such new requirements.
We propose a modern networking approach for intelligent subsea completions using common practices of the process control and information technology (IT) industries. Downhole sensing and control would operate on fieldbus-like protocols, widely used in automated plants and petroleum refineries. For interfacing intelligent completions from the seabed to topside supervision, our approach uses transmission control protocol running on top of internet protocol (TCP/IP). These communication layers (Levels 3 and 4) in the open systems interconnection (OSI) model bring full flexibility for dynamic device configuration and reconfiguration, data file handling capability, compact and modular software interfaces at topside, and flexible interface with various vendors. This initiative is now endorsed by the Intelligent Wells Interface Standardization (IWIS) panel1 , which is now drafting an International Standard Organization (ISO) standard for the industry.
For subsea operators, the networking approach using industry standards offers a seamless integration between topside systems and various downhole vendors, and opens future options of object-oriented protocols among all topside processes. Seamless integration reduces interface costs and decreases software interface developments. The overall system reliability will increase, thanks to standards and mature equipment widely supported by all the telecom and computer industries.
