OILFIELD
Inhibex® Series Low dose Kinetic Hydrate Inhibitors
Low Dose Hydrate Inhibitors (LDHIs) based on Poly Vinyl Pyrrolidone (VP) and Poly Vinyl Caprolactam (VCap) retard gas hydrates by functioning as “anti-nucleates.” Specifically, as kinetic hydrate inhibitors, these technologies interact with crystal growth sites to delay hydrate nucleation. ISP offers the Inhibex® series of low dose gas hydrate inhibitor technologies to delay gas hydrates in offshore production systems. These products are typically 25 to 50 times more efficient than thermodynamic inhibitors. Most Inhibex gas hydrate inhibitors require less than 1% (wt.%) to prevent gas hydrates from forming, even in fields with high water cut. Formulations containing Inhibex products may be used as a stand-alone option or as technologies to enhance the efficiency of standard thermodynamic gas hydrate inhibitor methods.
Deploying LDHIs in demanding field applications
Today, oil and gas operators work within a larger spectrum of temperature and pressure conditions. ISP has responded to these changing operational conditions with novel polymer based chemistries designed to withstand variables such as high injection temperatures, high salt conditions and high sub-cooling conditions, North Sea biodegradability requirements and even remain functional in the presence of condensate. Now more than ever, ISP is expanding the application of low dose KHI chemistry for formulators of hydrate inhibitor products.
Benefits Lower dose rate vs. standard THI’s Subcooling performance up to 11.5°C in ISP lab tests Salt and temperature tolerance at certain conditions Moderate viscosity for consistent formulation Comparable subcooling vs. 25% dose rate methanol Methanol compatible Lower environmental impact than methanol
IN
The Inhibex product range
Most oil & gas production systems are subject to conditions favorable to gas hydrate formation. ISP, a major supplier of kinetic gas hydrate inhibitor technology (KHI), specializes in both Poly Vinyl Pyrrolidone (VP) based KHIs developed in the 1990’s and new, novel Poly Vinyl Caprolactam (VCap) copolymers and terpolymers. Included here are commercially available Inhibex products based on innovative ISP chemistry: 301
501
505
510
BIO 800
Poly VCap/ DEAEMA
Poly VP/VCap
Poly VCap Co-Polymer
Poly VCap Co-Polymer
Poly VCap Co-Polymer
Solvent
BGE
BGE
EG/Water
BGE
BGE
Induction time at 10.5°C subcooling (60 bar, 7°C)
4-5 d
3-5 d
>4d
13 d
13 d
Max subcooling (°C) with 2 day induction time
10.5
10.5
11.5
11.5
11.5
Fresh water cloud point (°C)
37
72
89
28
29
Fresh water precip point (°C)
~100
98
~100
33.5
~100
No
Yes
Yes
No
No
Performs in presence of condensate
General purpose KHI with high cloud point
High temp, High salt tolerant
High subcooling KHI
Biodegradable, High subcooling KHI
Chemistry
Salt tolerant
Notes
Inhibex 301 multipurpose gas hydrate and corrosion inhibitor
A copolymer of Vinyl caprolactam and N,NDiethylaminoethylmethacrylate in Butyl Cellosolve, Inhibex 301 offers gas hydrate inhibition along with the added benefit of corrosion inhibition properties. At a dose rate of 0.6 wt.%, Inhibex 301 performs well in the presence of condensate at 10.5°C subcooling in autoclave cells containing green canyon gas. Tests conducted alongside standard poly VCap polymers show Inhibex 301 yields benchmark subcooling performance at 10.5°C in autoclave cells containing green canyon gas.
Inhibex 501 gas hydrate inhibitor
Setting the high cloud point benchmark Operating wells with high injection temperatures require gas hydrate inhibitors designed for cloud points above 50˚C. At the same time, commercially viable KHI technologies must exhibit industry standard subcooling performance. ISP offers both with Inhibex 501. Based on poly VCap copolymer, Inhibex 501exhibits a cloud point at 72°C, well above other commercially available Inhibex gas hydrate inhibitors. In many injection applications, cloudiness is acceptable while the critical temperature is the precipitation temperature of the polymer. Inhibex 501 offers a precipitation temperature of 98°C in fresh water and a 45°C precipitation temperature in brine.
Temperature/Salt tolerance of Inhibex 501 Inhibex 501 offers high cloud point and moderate salt tolerance benefit. With an induction time of 3-5 days at 10.5˚C subcooling, Inhibex 501 exhibits good performance and high temperature compatibility.
wt% methanol 15
25
1600
No inhibitor
5
1400
Inhibex 510 0.6 wt% 1200
100 90
1000
Precipitate Region
70 60
Pressure (psi)
Temperature (°C)
80
Haze Region
50
800
11.5°C SubCooling
40
600
30
Clear
20
400
10 0 0
2
4
6
8
10
12
14
16
18
20
200
% Brine (NaCl)
Matching sub-cooling benchmarks with co-polymers Prior to the introduction of Inhibex 510, a poly Vcap co-polymer, few alternatives existed for high sub-cooling performance. Standard poly VCap, used successfully in the field for decades, is the industry standard for KHI performance. Tests conducted alongside standard poly VCap polymer, however, show Inhibex 510 co-polymers yield subcooling performance of 11.5°C in autoclave cells containing Green Canyon Gas. At a dose rate of 0.6 wt%, Inhibex 510 is comparable to 25 wt% methanol as well as industry standard Poly VCap. This high degree of efficiency suggests a potentially lower cost solution than thermal technologies. Highly compatible with methanol, Inhibex 510 may also be used to enhance the efficiency of standard thermodynamic gas hydrate inhibitor methods.
0
5
10
15
20
25
Temperature (°C)
Subcooling induction time of Inhibex 510 Induction times vary with subcooling as shown below. Excellent subcooling results are seen with Green Canyon Gas in autoclave cells at 0.3 wt%. ISP considers the neat polymer to pass our testing at 11.5°C max. 350 300
Induction Time (hours)
Inhibex 510 gas hydrate inhibitor
0
250 200 150 100 50 0 10
11
12
13
14
15
16
Degrees of Subcooling (°C)
Temperature/Salt tolerance of Inhibex 510 Temperature vs. % brine plot below indicates the operating window where Inhibex 510 is clear, hazy and precipitates. While the temperature, salt tolerance window is narrow, Inhibex 510 offers excellent subcooling under certain conditions. 50
40
Temperature (°C)
Given these capabilities, Inhibex 501 is considered ideal for use in operations with high injection temperatures and moderate subcooling requirements.
30
Precipitate Region
20
Haze Region 10
Clear 0 0
2
4
6
8
10
12
% Brine (NaCl)
14
16
18
20
Inhibex products from ISP
ISP offers an expanding list of Inhibex gas hydrate inhibitors to better support a range of offshore operating conditions. Products like Inhibex BIO 800 – engineered for high subcooling performance: • • • •
Offer>20% biodegradability as defined by OECD 306 guidelines Better support of regulatory requirements in regions such as the North Sea Excellent sub cooling performance at low dosage rates The potential to lower overall hydrate inhibitor costs
In high injection temperatures and high salinity conditions, ISP offers Inhibex 505: • • •
For very high temperature/salt tolerance Excellent sub cooling performance at low dosage rates Does not precipitate out at 100°C up to 10% brine
For more information about these and other products made possible with ISP’s broad portfolio of innovative chemistry, visit ispenergy.com or contact your ISP representative.
For questions about any ISP Oilfield products, visit ispenergy.com Or to find a sales office within your country visit ispcorp.com '/#+. (4#0%' )'4/#0;
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