Drive system helps maximise oil and gas field productivity

Boosting extraction from depleting reserves is part of a project that aims to enhance Oman’s hydrocarbon production capabilities and help the country broaden its economic base. It is expected that Oman will unlock about one trillion cubic metres of natural gas over the next 25 years. There are also plans to develop downstream industries such as the production of ethylene dichloride (EDC), caustic soda and other chemicals. 

As part of this major effort, the PDO Saih Rawl Field Depletion Project, Phase 2, aims to develop a daily gas production capacity of 30 million cubic metres, which will be fed to the existing Saih Rawl central processing facility. Extra compressors will be installed to increase the pressure so that gas continues to flow, enabling the field to feed the liquefied natural gas (LNG) industry while offering a back-up when other plants are shut down for maintenance.

Electric motors will play a key role in ensuring that compressors run efficiently, smoothly and reliably, as they will be responsible for driving their suction and discharge cooler fans. Because electric motor-driven systems (EMDS) are the largest individual source of energy use, and over half of this energy demand originates from motors used in fans and compressors, Indian company Larsen & Toubro decided to partner with WEG to equip the main gas compressor with an efficient drive system, to endure demanding applications.

WEG developed a bespoke solution comprising 30kW variable speed drives and motors and  15kW drives and motors, which will be supplied as systems and mounted in control cabinets,  which also includes a high capacity circuit breaker for emergency cut outs and a by-pass system for DOL (direct on line) starting. 

WEG has also fitted its equipment with a passive input harmonic filter to reduce problems relating to mains borne corruption of the power supply, while an output filter will be used to protect the drive.

WEG has also supplied Larsen & Toubro with all of the overloads, switchgear, relays and pushbuttons used within the drive cabinets to help ensure component compatibility and trouble free system building and commissioning as well as efficient ordering and delivery. Other elements in the cabinet include a control power transformer and auxiliary contactors and circuit breakers. Additionally, a door mounted control panel incorporates a backlit LCD keypad, while a redundant serial link provides communication to the wider control system. Finally, the control cabinets include space heaters, which are essential to withstand the extreme temperature differentials between day and night in the Oman desert, which can cause potentially damaging condensation.