Rightrax system helps BP maintain corrosion awareness in Columbia

Citation

(1999), "Rightrax system helps BP maintain corrosion awareness in Columbia", Anti-Corrosion Methods and Materials, Vol. 46 No. 1. https://doi.org/10.1108/acmm.1999.12846aab.007

Rightrax system helps BP maintain corrosion awareness in Columbia

Methods

Rightrax system helps BP maintain corrosion awareness in Columbia

Keywords Columbia, Corrosion, Corrosion monitoring, Pipelines, Rabco Industrial Inspection

We are informed that a new, totally integrated, corrosion monitoring system, from Rabco Industrial Inspection Ltd, of Poole, is helping BP to carry out programmed corrosion inspections and to monitor the efficiency of corrosion inhibitors on buried flowlines in remote and hostile locations in Columbia, in what is the first application of its kind anywhere in the world (Plate 1). Data from the inspections is transmitted to a central processing facility, by using the metal structure of the pipeline as a transmission path to a receiving modem. It can then be on-transmitted to any further location by radio or via the Internet.

BPX Columbia has formally adopted a "Corrosion awareness campaign" to save avoidable costs. As part of this campaign, it decided to take into consideration the lessons learnt in older BP assets worldwide and to try to prevent the increase in costs due to corrosion caused by corrosive fluids which can arise during plant life. The Cusiana flowline network is already extensive and is set for future growth. However, as all of the flowlines are buried and the surrounding countryside is particularly hostile, both in terms of terrain and in terms of sporadic terrorist activity, integrity monitoring is extremely difficult using traditional techniques. Because of the high temperatures in the flowlines (around 100°C), intelligent pigging is not considered a viable option, as pigs could damage the semi-protective corrosion product film, accelerating corrosion problems.

Plate 1 Schematic of the integrated corrosion monitoring system being used on buried pipelines at BPX's Cusiana facility in Columbia

Fortunately, BP Aberdeen was aware of the existence of the Rightrax system, which allows comprehensive inspection for internal corrosion, without the need for intelligent pigging, plant shut-down or exposing buried pipes. Consequently, Rabco were asked to carry out proving trials at BP Wych Farm, in Dorset, and then to develop the system to meet the requirements of BPX's Cusiana facility in Columbia, where it was installed earlier this year.

Three critical areas have been identified on each flowline and, specifically, these are areas where water drop-out is predicted. At each of these locations, ten Rightrax M1 flexible transducer arrays have been fitted, each configured to provide 14 individual sensors, providing a total of 140 corrosion measuring points at each critical area. The M1 sensors are connected together through a daisy chained, high temperature coaxial cable and the sensor and cable assembly is then fully encapsulated in the pipeline coating material. The coaxial cable is plugged into a DTS 2000 data transmission modem, which is integrated with an internal battery and a Rightrax DL1 data logger, which has built-in intelligence to collect, process and store the gathered data. The complete corrosion monitoring and data transmission system is then re-buried with the pipeline, protected against water ingress and mechanical damage.

Communication between data transmission modem and the remote central processing facility is via the metal structure of the pipeline itself, as the DTS 2000 uses extremely low frequency signals, with peak-to-peak voltages which sum to zero over time. The system power supply is provided by the internal battery, and this is recharged between transmissions by drawing a small current from the pipeline's local cathodic protection (CP) potential.

In operation, a start-up signal is sent to the DTS 2000 from the central processing facility and then "wakes up" the data logger, which interrogates every transducer on every M1 array, in turn. Data are collected relating to local thickness, temperature and CP potential and each data package contains the transducer identification and the inspection time. The data logger collects and processes the information, which is then transmitted by the DTS 2000 back to the central processing facility. Here a PC with a network interface can provide remote access to the information anywhere in the world.

According to Rabco, the new system is now allowing BPX Columbia to manage inevitable corrosion problems extremely cost-effectively. It is also allowing continuous monitoring of corrosion inhibitor efficiency, which again leads to cost saving as the usage of expensive corrosion inhibitor can now be optimised.

Rightrax systems are marketed, employed and supported worldwide by Rabco Industrial Inspection Ltd of Poole. In their various configurations, they find application throughout the process industries, especially in the oil and gas sector, for local and remote corrosion monitoring of buried pipelines and of pipelines and vessels in remote or hazardous areas.

For further details contact: Rabco Industrial Inspection Ltd. Tel: +44 (0)1202 681971.