This paper will document a mapping process undertaken to quantify data sources within BP's subsea assets during 2005. An important additional goal of this paper is to provide feedback to the many instrument and subsea control system vendors who provided valuable input to the work. The initial need for a subsea data-mapping exercise was identified following a similar exercise covering BP's topside data sources for the field of the futureTM program. The aim has been to quantify current subsea data types together with likely trends, to inform both field of the futureTM activities and future BP subsea control architecture use. The paper concludes that a) the umbilical still presents a major restriction to improvements in data flow within subsea control systems; and b) looking at how current developments in subsea communications technology may be focused to meet BP's future goals.
In early subsea developments telemetry data was limited to basic analogue transducers each with its dedicated connection to the surface. With the advent of multiplex control systems that needed to meet the growing complexity and step-out distances, a potential for far greater levels of telemetry became practical. The effective data rates of early systems were typically 1200 b/s. This compared well to dial-up modem speeds used for computer access at that time, which were often no quicker than 300 b/s. However, with the limited range of connected instruments field update times were more than adequate for effective production monitoring. Moving quickly forwards to the present day, the fastest communication speed for a control system installed last year?by BP for the Gulf of Mexico FMC Thunder House and Nakika projects-was only 2400 b/s. While there are faster copper and fibre based systems in the market place, these have their own drawbacks, for instance in terms cost, or implementation difficulties with longer step-outs. The initial need for a subsea data-mapping exercise grew out of a concern that potentially useful data was being delayed or left subsea because of the limited data bandwidths available. This followed a similar exercise covering topside data sources for the field of the futureTM program. The field of the futureTM project was intended to define and develop methods of utilising advanced technologies and processes, while accelerating ?better decisions faster? around production, expense and investments. The stated aims of the data mapping activity were therefore:
To quantify current subsea data types together with likely trends
To inform BP's ongoing field of the futureTM program on the potential problems associated with trying to exploit subsea data fully
To improve BP's future use of subsea controls technology
Figure 1 shows the basic processes followed for the subsea mapping. To make the results more relevant Rhum, Schiehallion and Greater Plutonio were chosen as ‘real’ data sources for the work. Data from these was combined with a selection of other instrument and controls suppliers to build up a complete picture of the subsea data environment. Information was collected through directed interviews and questionnaires with follow-up telephone conversations where needed.
