The Tamar Project: Novel Deepwater Pipeline Pre-Commissioning and In-Line Inspection Capabilities
Proceedings Publication Date
This paper will focus on the novel engineering and pre-commissioning techniques developed to deliver the Tamar field in a time and resource efficient manner, without compromising on quality of service, safety for all personnel and environmental stewardship. Weatherford, Pipeline & Specialty Services have recently performed the pipeline pre-commissioning services for Noble Energy Mediterranean Ltd. on the new Tamar field, offshore Israel. This development involves a subsea gas production and transportation system connecting the deepwater Tamar Gas Field to an offshore receiving and processing platform. Gas production from the Tamar Reservoir now travels through five high flow rate subsea wells into the subsea gathering system, which consists of an infield flowline (typ. 3 miles long) from each well to a subsea manifold. From the subsea manifold in 5,400ft water depth, dual 16” subsea pipelines run 93 miles to the Tamar Platform, 790 ft water depth, for processing. The processed gas will then be delivered to the existing Ashdod Onshore Terminal (AOT) for gas sales into the Israel Natural Gas Line (INGL) system. Weatherford’s main pipeline pre-commissioning scope consisted of: Tieback Pipelines: 2 x 16” x 93 miles; 790ft – 5,400ft water depth •Subsea filtered free flood, vessel based pumped flood, clean, gauge and hydrotest •Base Line Survey: Weatherford Multi-Channel Calliper and Ultrasonic Wall Measurement inspection pigs were run during the pumped flood operation. Weatherford provide a turnkey package combining pre-commissioning and deepwater in-line inspection. •Vessel based nitrogen dewatering and packing. In-Field Flowlines: 5 x 10” x 3 miles; 5,400-5,500ft water depth •Subsea flood, clean gauge and hydrotest (remote logging capabilities) with Weatherford’s Denizen subsea pre-commissioning system. Subsea launch of dewatering pig trains using subsea Mono Ethylene Glycol (MEG) skid and Denizen pumps. •Nitrogen pack pressure of tie-backs used to provide gas for dewatering of all in-field flowlines without nitrogen pumping at the deepwater section. This is a novel technique employed to save vessel time and equipment costs involved with directly dewatering the deepwater flowline sections.