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Northwest Europe can store, mix and pump polymer. planned, as well as pre-investment in key

Others have been considering offshore polymer EOR facilities. As a result, it hopes schemes, with Statoil working on pilots at it can maximize recovery to above 30%.

Key to the project has been improving

Heidrun, Norway, and Peregrino, Brazil. liquids handling capability. The Glen

BP now looks set to join the polymer party.

Further to its multi-billion pound rede- Lyon, due onstream in 2016, will have velopment of the Schiehallion and Loyal 320,000 b/d liquids capacity. It will be felds, known as the Quad 204 project, needed. Some 380,000 b/d of water injec-

West of Shetland, BP has been consider- tion capacity will be installed to sweep ing introducing polymer EOR. The Quad the feld and maintain pressure, with 204 project involves a newbuild FPSO, the vessel having a capacity to produce the 270m-long Glen Lyon, which will 130,000 bo/d. become the North Sea’s largest unit once For Quad 204, which had been under operational, onto which BP is planning to a water food scheme since 1998 (with pre-invest in key polymer injection facili- 50%+ water cut in places), a large part ties. If the subsequent polymer project of the beneft of polymer is that, through goes ahead, it will be the frst deepwater reducing the mobility of the water, less subsea polymer EOR project. water will be produced, freeing up valu-

An intense subsea campaign is ongoing West of Shetland, ahead of the FPSO’s arrival. able plant capacity for more infll wells

Photo by chrisallanphotohraphy.com.

Quad 204 or tieback opportunities.

Quad 204 is 175km West of Shetland. “When you inject regular water in to more wells and accelerate production.” expensive for subsea wells.

Schiehallion was discovered in 1993, the feld, the water fngers through the “Every restriction poses an opportunity

Powder or emulsion? and Loyal a year later, with production reservoir and leaves oil that has not been to damage the polymer,” Thomson says. starting in 1998 from the Schiehallion swept, which can get left behind,” says Once a decision has been made to use “The polymer unfurls in the dilution

FPSO, which the Glen Lyon replaces. Scott Thomson, area subsurface man- polymer, the next step is looking at how process to the specifed viscosity. If the

Schiehallion and Loyal together had ager, BP. “If you use polymer, instead of it is deployed, including in what form it polymer chain is then stretched and more than a billion barrels in place and creating fngers, the polymerized water is supplied, and overcoming the chal- sheared as it passes through a restriction, recovery to date had been about 15%. moves in a more piston-like and effcient lenges around deploying it. it loses some of that viscosity. You could

Recognizing the greater potential of the manner. That is the traditional industry There are two ways polymer can be overdose the polymerized water, but all area – BP has produced ~400 MMbo to application of polymer food. supplied, in powder form and, more the wells are choked at different rates, so date and thinks there’s a similar amount “Quad 204 is a bit different,” Thomson recently, as an emulsion. In most onshore the polymer will shear differently in each to be had – and both the falling effciency says. “Our new wells will beneft from deployments, polymer is supplied in a well. We are looking at ways to get the and limitations of the original Schiehallion the traditional mechanism of piston-like powder form, which requires a mixing target viscosity to the reservoir without

FPSO, the operator, with partners Shell sweep, but because we have already pro- process before it is injected downhole. shearing the polymer. We have ideas how and OMV, decided to redevelop the feld duced several millions of barrels from the The risk with having the polymer sup- we can overcome these problems and through the Quad 204 project, investing in feld and we have been injecting water plied as powder, especially offshore, improve commercial performance.” the new, higher capacity Glen Lyon FPSO, for some time, there are huge chunks is ineffcient powder wetting, creating

Wider beneft subsea infrastructure renewal, a seven-year of the feld where the water has already inconsistencies in the mix, which can drilling program, with at least 20 new wells broken through at the producers. adversely impact well injectivity. BP is also working with vendors to test “We are less interested in delaying water

As an emulsion, the polymer molecu- polymers for this application. Getting breakthrough in these areas and more lar chain is delivered coiled up within a it right could be a game changer for interested in capturing some of the oil that water droplet, within an oil main phase. the vendors, as well as BP, Thomson has been left behind via the mechanism of

Water is then added to the emulsion, says. A successful EOR project in the viscous cross fow,” he says. Viscous cross which allows the water droplets to join, Schiehallion and Loyal felds will create fow happens when pressure gradients cre- enabling the polymer chains to unfurl and a large demand for polymer, the produc- ated by the polymer-food force water into link, causing the water to viscosify. This tion of which may require new manufac- parts of the reservoir that were previously is called “inverting” the emulsion. “We turing facilities. This in turn would make bypassed by fngering. believe the emulsion will be easier for us polymer for EOR more widely available

Using polymer will also have another, to handle and to prepare for injection in to the broader industry. signifcant, benefcial effect. Despite the relatively harsh environment, deepwa- Although the Quad EOR project is still being set to be the biggest FPSO in the ter, West of Shetland,” Thomson says. only in concept development with sev-

North Sea, the Glen Lyon will still have The next challenge is deployment. eral technical and commercial hurdles to limitations, i.e. there’s only so much Many large offshore felds that could be overcome, BP and its partners are work- water you can produce. This would mean suitable for polymer EOR may be viewed ing hard to make polymer deployment in that production has to be choked back. as having limited application because the North Sea a reality. “We want to reduce the fractional fow of they have been developed using subsea *SPE paper SPE-144932-MS, pre- water into our facility and polymer helps wells. Offshore, because the polymer sented at the SPE Enhanced Oil Recovery us do this,” Thomson says. “The polymer is injected from topsides, it has to go Conference, Kuala Lumpur, 2011.

effectively slows down the water in the through various restrictions, such as

OE would like to credit SPE Aberdeen reservoir and means the water cut is the choke, as it fows into the wells. and DEVEX, which held events at which reduced at the surface. With less water Onshore, injection could be downstream

Thomson and Collins spoke about the project, respectively.

coming to the surface, we can open up of the choke, which can be prohibitively oedigital.com September 2015 | OE 87 086_OE0915_Geofocus3_Quad204_1.indd 87 8/19/15 11:33 PM