VISCOPLEX® crude oil paraffin inhibitors improve efficiency

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VISCOPLEX® crude oil paraffin inhibitors (COPIs)Crude oil is a very complex mixture of hydrocarbons. Some with very high paraffinic wax can create critical flow problems, even at ambient temperatures. This is due to high melting points and long-chain paraffin crystallizing at the cloud point or below. In general, there are three problems: increased viscosity, a higher pour point, and increasing wax deposition. A number of methodologies have been employed to fix the flow problem, such as using pigging, heating, solvent dilution, and a paraffin inhibitor. Depending on the specific conditions, one methodology or combination of several are used to achieve the most economical method to keep the crude oil flowing.

Crude Oil Paraffin Inhibitors, or “COPIs,” have been developed by the Oil Additives specialists at Evonik to solve this problem. Evonik’s COPIs modify the size and the shape of the wax crystals, dispersing them and preventing them from adhering to pipeline or transporting vessel surfaces.

Evonik’s crude oil paraffin inhibitors provide important benefits in:• Crude oil recovery• Flow assurance• Storage

Virtually all paraffinic mineral oil base stocks contain small amounts of waxy materials. As the temperature of the oil is decreased, some of the waxy components come out of solution as tiny crystals, and the solution begins to appear hazy to the naked eye. The temperature at which this occurs is called the cloud point. As additional wax precipitates, the crystals grow into plates and, finally, if the temperature is decreased far enough, the plates will grow together to form a three-dimensional network that totally immobilizes the oil. This solidification process is sometimes referred to as gelation. The lowest temperature at which the oil is fluid is called the pour point.

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Wax crystallites can start forming in crude oil at temperatures as warm as 60°C (140°F), as these temperatures are below the cloud point of wax. Due to the wax crystal formation, the crude oil becomes a non-Newtonian fluid. Its viscosity increases quickly when the temperature continues to drop during transport. Thus, productivity diminishes, increasing pump pressure, and eventually stopping flow due to wax solidification.

In deep water drilling, this problem is amplified many times over as the deeper the drilling, the colder the water surrounding the pipeline, leading to significantly more wax deposits.

At a depth of 1,000 meters (3,280 ft.), sea water is about 4°C (39°F). At this temperature, a wax network forms inside the pipeline, trapping sand and silt particles. Additional wax molecules attach, increasing deposition hardness and further narrowing the pipe diameter.

Decreased flow and lost productivity are expensive. Oil industry insiders cite one specific repair job that ran into hundreds of millions of dollars.

Wax deposition will occur on the cold surface of the pipeline

70-150°C within the oil reserve

5°C at the surface of the pipe

Flow line

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Wax molecules Sand and silt particles

Wax crystallites form at temperatures as warm as approximately 60°C

Effective pipe diameter decreases, flow rate drops, productivity suffers

Wax network forms, trapping sand and silt particles

Additional wax molecules diffuse into deposit, increasing hardness

Without crude oil paraffin inhibitors

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Sea water temperature gradient

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To ensure crude oil flows efficiently, some state-of-the-art techniques are combined and used, such as heating and insulation, pigging, solvents, dispersants, hydrate inhibitors, asphaltene inhibitors and paraffin inhibitors.

Evonik’s paraffin inhibitors are based mainly on polyalkyl methacrylate chemistry (PAMA). By varying the length of the PAMA molecule’s alkyl side chains, Evonik tailors the structure-property relationship to modify wax crystal growth in crude oil.

Evonik’s COPIs prevent the interlocking of wax crystals, leading to smaller and more random structures. As a result, the crude oil continues to flow without the build-up of a wax network.

The technology behind Evonik‘s crude oil paraffin inhibitor

Without VISCOPLEX® COPI With VISCOPLEX® COPI

Densely structured wax formation Randomly dispersed wax crystals

Evonik’s paraffin inhibitor chemistry

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Analytical techniques for COPIsThe effectiveness of crude oil paraffin inhibitors varies depending on the type of crude oil to which it’s applied. To determine the most effective paraffin inhibitor, the Oil Additives specialists at Evonik conduct various analytical screening evaluations and employ techniques using state-of-the-art equipment.

Analytical screening techniques:• Cloud point• Pour point• Differential scanning calorimeter• Rheometer• Brookfield cone and plate• Cold finger

Cold finger analytical techniqueDue to better correlation with field performance, “Cold finger” is the preferred screening method to identify an effective flow improver or paraffin inhibitor. In the graph to the left, three VISCOPLEX® products were tested by cold finger testing in one crude oil for six hours.

VISCOPLEX® COPIs performance in a North American crude oil measured by a cold finger test (up to 88% wax deposit reduction is found in this study)

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VISCOPLEX® COPI A, wax deposit ratio VISCOPLEX® COPI B, wax deposit ratio VISCOPLEX® COPI C, wax deposit ratio

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Test results

Effective reduction of Pour Point (PP) and wax deposit by changing COPI chemistry

PP D97 [°C] Change in wax deposition [%]

Sample Treat rate MO1 MO2 MO3 MO1 MO2 MO3

0 ppm 30 40 55 n/a n/a n/a

COPI 1

500 ppm -2 17 55 0 -42 26

1000 ppm -9 20 55 -19 -49 9

2000 ppm -24 21 55 -34 -15 26

COPI 2

500 ppm 18 26 55 -69 2 -41

1000 ppm -24 -13 55 -52 4 -52

2000 ppm -13 6 55 -60 64 -50

COPI 3

500 ppm 17 26 -14 -26 -55 22

1000 ppm 11 17 28 -38 -40 3

2000 ppm 12 13 42 -72 -20 -10

COPI 4

500 ppm 26 28 39 0 -42 26

1000 ppm 26 27 36 -19 -49 9

2000 ppm 12 23 46 -34 -15 26

COPI product summary

For regular crude For heavy crude Tailor-made

14-900 14-301

We will develop customized products to meet your specific needs.

14-921 14-302

14-924 14-303

14-927 14-304

14-950 14-401

14-982 14-402

Figure 1: Wax deposit on cold finger surface.

COPIs for environmentally- friendly lubricantsDemand for environmentally-friendly lubricants is growing due to environmental concerns and strict government regulations. Evonik can help address these concerns by designing VISCOPLEX® crude oil paraffin inhibitors to meet rigorous environmental protection requirements.

Get an edge with EvonikWith plants in the US, Canada, Europe and Singapore, the Oil Additives specialists at Evonik create custom solutions using paraffin inhibitors to meet each customer’s specific needs.

Evonik provides worldwide technical support and is engaged in continuous product development. Its innovative, tailor-made products give customers “an edge” in beating the competition, and helping them to “future-proof” their business against industry challenges.

To learn more, contact Evonik’s Oil Additives specialists at oil-additives@evonik.com.

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United States

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HeadquartersRegional officesTechnology centersManufacturing facilitiesSales offices & representatives

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This information and all further technical advice is based on our present knowledge and experience. However, it implies no liability or other legal responsibility on our part, including with regard to existing third party intellectual property rights, especially patent rights. In particular, no warranty, whether express or implied, or guarantee of product properties in the legal sense is intended or implied. We reserve the right to make any changes according to technological progress or further developments. The customer is not released from the obligation to conduct careful inspection and testing of incoming goods. Performance of the product described herein should be verified by testing, which should be carried out only by qualified experts in the sole responsibility of the customer. Reference to trade names used by other companies is neither a recommendation, nor does it imply that similar products could not be used.

VISCOPLEX® is a trademark of Evonik Resource Efficiency GmbH or one of its subsidiaries. ©05/2017 EVONIK INDUSTRIES AG – v8

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