Steam Boiler Integrity Strategy for Complex Steam Generators in Thermal Operation Facility

Abstract

Abstract Petroleum Development Oman LLC (PDO) is Oman’s premier oil producer and operates several fields. Thermal Development is one of key enablers in Oman for significant Oil Recovery. “A” facility is designed to receive Aquifer Pump-off (APO) water from a reservoir and utilize it for steam generation once treated in Water Treatment Plant (WTP). Thermal Enhanced Oil Recovery application in Oman has been first operated in Gulf region back in 2012 with enormous lesson learned insights on selecting and operating water treatment facilities. The Purpose of Water Treatment plant is to remove hardness of APO Well Water to make it suitable for Steam generation. The processes involve the removal of suspended solids and, traces of oil and dissolved minerals from water. Quality of boiler (steam generator) feedwater is of critical importance in steam injection projects. Field experience indicates that most generators downtime is caused by water treatment performance concerns, hence operating outside water quality specification results in damaging mechanisms of the boiler tubes i.e., corrosion and scaling deposition. The project steam consists of 10 steam boilers of various type with total steam production of 20k tones/day responsible to produce 30k net oil/day. Steam availability has been the most significant challenge for meeting oil productions target for Steam Enhanced Oil Recovery Fields. However, maintaining safe operation of boilers at “A” facility has come with huge annual OPEX cost of > $3mln annually from boilers inspection, tube repair, and associated oil deferment due to steam unavailability during maintenance. A comprehensive engineering approach through setting detailed boiler integrity strategy and traffic lights criteria assessments development of API-530/ASME assessment while integrating that with detailed corrosion rate calculation and proper utilization of Fitness for Service API-579 in the right context. The objective of this paper is to generate a robust integrity strategy management of steam boilers along with significant economic benefits of cost savings around $1.5mn/year. This has proven to be the standard boilers integrity strategy to be implemented for first time in Oman and has been cascaded for all other EOR applications.