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The Challenge
As Sygnology implemented its feature extraction techniques on the client's instrument data, we discovered a previously non-existent trigger signal energy signature in the Waterflood Turbine Gas Producer bearings which were manifested shortly after it was restarted in the wake of a shutdown due to an incoming Hurricane.
The Investigation
The strength and duration of these trigger signal energy signatures reviewed lead to the conclusion that the source of the anomalous, repetitive signal was the anti-cavitation valve as it is most consistent with the observed features and physical principles. A comparison of the shape of the primary trigger signal energy signature to variable process conditions revealed highest correlation to valve throughput (valve position is a proxy for flow rate) and differential pressure across the valve. The intensity and characteristics were best explained as a function of energy dissipated by the overboard control valve. The historical review of past valve performance and failures indicated that the observed anomaly was evidence of active and worsening damage to the valve. Historically, the analysis revealed that this same kind of damage has proceeded for a maximum of 2 - 4 months prior to experiencing performance issues. Additionally, this damage was found to be reduced or eliminated when valve discharge pressures rose to levels greater than 220 PSI.
The Solution
The source of these anomalies was identified based on the characteristics of shape and intensity of the extracted patterns. In order to identify the source of this trigger signal energy signature, numerous historical process values were analyzed. Each process value analyzed generated a varying trigger signal energy intensity depending on the type of instrument and its location, with normalized intensity values being highest closest to the source of the underlying pattern.
The Results
It remained unknown if the damage that had already occurred could have been halted at the point of discovery, but the client and Sygnology recommended the platform operators take any available action via process adjustments to eradicate this trigger signal energy signature, strongly suggesting the valve discharge pressures once again be raised over 220 PSI to minimize low-flow wear on the thrust bearings.
These findings were readily accepted and corroborated by observations of the platform team. Probable action reported an assignment of $2.5 million over the life of the field as a result of the information and advice provided by Sygnology.