With the successful deployment of its new large bore SIM plug systems at Apache’s Sinbad field on the North West Shelf, Peak Well Systems chalked up an industry first offshore Australia earlier this year. Russell McCulley pays a visit to the ten year-young company’s Perth branch to hear how they are scaling up the slickline-conveyed and recoverable plug technology.
Operator Apache Energy met with the Peak Well Systems engineering team in July last year to discuss the deployment of SIM plugs at Sinbad, a natural gas producing monopod in 38m of water that links into Apache’s gas and liquids processing hub on Varanus Island. The two companies had worked together before, having previously used smaller bore SIM systems, mechanically set plugs that require no nipple profile within the tubing wall and can be set without the use of electric line or explosives. The new job however, required plugs for 5in and 5.5in tubing that could be fast-tracked for deployment in advance of the Western Australian cyclone season.
‘Apache wanted to plug wells on the platform prior to a rig moving in to suspend the wells. As such they needed to put barriers in the bottom of the wells and then cement them,’ explains Peak’s director of technology Dave Manson. ‘They came to us and asked, “Can you make us a larger bore slickline set of SIM plugs for these wells?” which happened to be 5in and 51/2in diameter.’
At the time, adds Manson, Peak’s SIM system – an abbreviation for slicklineinstalled mechanical set plugs – topped out at 4.5in. The system consists of a plug and expandable seal that can be set by mechanical tool string manipulation at any depth within the tubing. Once in place, the plug is set by downward jarring, which activates a specially designed low-force expandable seal. Once set, a confirmation ‘tell-tale technology’ check can be made to ensure the plug has set as required, before upward jarring releases the running tool device. The major technical challenge in scaling up the technology, notes Manson, was to design a seal element that could be energized with the minimal force available from toolstring manipulation.
Although the three Apache wells at Sinbad were to be permanently plugged, the company opted to use retrievable SIMs to ensure that the devices could be removed in the event the program changed or if any issues arose while running before the rig was on location. The plugs were set at 2000m, the lower point of the desired well barrier, and at 100m to create the upper seal. In addition to plugs, the SIM product line includes retrievable straddles, permanent cast iron plugs, large bore gauge hangers and leak detection tools. Peak is currently preparing a new dynamic underbalance system, called FloWell, for launch later this year.
All of the SIM products can be run on the same running tool, which uses collet fingers to latch into SIM devices, a continuous radial indexing mechanism, variable drag spring configurations to interface with the tubing and serrated slips to ‘bite’ into the tubing wall. A slickline-set large bore gauge hanger tool can be used to carry data acquisition devices or to anchor instruments or equipment that need to be suspended in the wellbore. Peak also manufactures a SIM permanent bridge plug for well abandonment or permanent zonal isolation applications.
Apache hoped to have the reversible barriers in place before bringing in a rig for final completion operations, Manson says. ‘They could have done all this work when the rig was there. They could run plugs in from the rig, but rig time is expensive. What they wanted to do was set plugs in these wells long before the rig ever came, because that was going to save them significant time and money. And they would have time to ensure the integrity of these plugs before the rig arrived.’
Apache considered traditional plugs set by electrical line, or E-line. But the ageing platform had limited deck space for equipment, and its crane had been rated downward to a maximum lift far less than the average weight of a typical E-line unit. To use E-line deployed plugs, Apache would have had to contract a crane barge and crew.
The operation ‘was getting expensive,’ says Peak chief executive Nigel Avern. ‘Our selling point is, you can deploy our plug anywhere on slickline and with our “tell-tale” technology be assured that it has been successfully deployed,’ he says. ‘Everyone generally has slickline available. So there’s no extra operational cost, no added logistical nightmares, and no explosives involved.’
Apache and Peak, working with the operator’s slickline service provider, were able to install the three retrievable SIM systems with a portable slickline unit that could be lifted aboard the Sinbad platform with the existing crane. The operations went off without a hitch.
Jack Goodacre, petroleum engineering manager for Apache, described the procedure at the time as offering ‘a reliable and straightforward solution to suspending activity on monopod wells which we may access at a later date’.
When Peak announced the successful deployment in February this year, Avern called the development of 5in and 5.5in retrievable SIM plugs ‘a major step forward for the well intervention market’ while noting the technical challenges of being able to mechanically set such large plugs. The technology has since been used by other operators, and is being scaled up for even larger applications. ‘We’re working on 7in SIM plugs as we speak,’ Avern says. OE
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