Design and development of N-vinylcaprolactam copolymers as kinetic hydrate inhibitors for sour gas environments

Imran, Muhammad; Saleem, Qasim; Ajwad, Hassan A.; Makogon, Taras Y.; Ali, Shaikh A.; Rushaid, Anas; Panda, Saroj K.; Al-Eid, Manal; Alawani, Nadrah A.; Aleisa, Rashed; Jabran, A.A.; Elanany, Mohamed

doi:10.1016/j.fuel.2021.122497

Cited by 15 publications

(17 citation statements)

References 27 publications

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“…Gas hydrate formation, corrosion, wax, scale deposition, and asphaltenes are the major flow assurance issues for oil and gas production . The use of special chemicals as inhibitors has been reported as the most effective method to control these problems. , Gas hydrates are noncovalently bonded compounds that form at high pressures and low temperatures in the presence of water and some gases, such as CH 4 , C 2 H 6 , and CO 2 . − The formation of hydrates inside the oil and gas transportation pipe can make a plugging problem and increase operation costs. , Kinetic hydrate inhibitors (KHIs) have been developed since 1990s as a cost-effective approach to inhibit the formation of gas hydrate in the production flowlines. − KHI formulations mainly contain water-soluble polymers, solvents, and synergists that are used at low concentrations (<3 wt %). ,− KHIs effectively prolong the nucleation period of gas hydrate crystals and prevent their growth. , Poly( N -vinyl caprolactam) (PVCap), poly( N -vinyl pyrrolidone) (PVP), and poly( N -isopropyl methacrylamide) (PNIPMAM) are well-known commercial KHIs. ,,, Among them, PVCap has been investigated extensively in the laboratory and industry under different conditions. − Generally, the inhibition efficiency of new KHIs is compared with the VCap homopolymer as a standard. , …”

Section: Introductionmentioning

confidence: 99%

Development of Highly Efficient Dual-Purpose Gas Hydrate and Corrosion Inhibitors for Flow Assurance Application: An Experimental and Computational Study

et al. 2022

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Gas hydrate and corrosion inhibitors are widely used to ensure successful and economic hydrocarbon stream flow inside the oil and gas pipelines. However, compatibility problems are observed during their co-injection into the flowlines as they have different molecular chemistry. Modifying effective gas hydrate inhibitors, such as polyvinylcaprolactam (PVCap), with some active functional groups in corrosion inhibition, can overcome compatibility issues. In this study, maleic anhydride was used as a cheap monomer to synthesize ionic N-vinyl caprolactam/maleic-based copolymers (P(VCap-co-MA)) as potential dual-purpose gas hydrate and corrosion inhibitors. The gas hydrate experiments showed that the inhibitors effectively inhibited natural gas hydrate formation and a maximum subcooling temperature of 14.6 °C achieved in a solution containing 2500 ppm P(VCap-co-MA)-3. The molecular dynamics simulation revealed that P(VCap-co-MA)-3 reduced the gas concentration in the liquid phase and occupied its adsorption sites on the hydrate surface to form a steric hindrance effect, inhibiting the gas hydrate formation. Electrochemical measurements indicated that P(VCap-co-MA)s significantly suppressed steel corrosion in oilfield-produced water saturated with H2S and CO2. P(VCap-co-MA)-3 and P(VCap-co-MA)-5 provided the highest protection of 96.9 and 96.1% in H2S and CO2 media, respectively. Moreover, simulation studies demonstrated that the inhibitors are strongly adsorbed on the steel surface to form a barrier layer on the surface, protecting against corrosive electrolytes. These findings suggest that the modification of a gas hydrate inhibitor improves not only its corrosion and gas hydrate inhibition performance but also decreases the operation costs for flow assurance in the oil and gas pipelines.

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Section: Introductionmentioning

confidence: 99%

Development of Highly Efficient Dual-Purpose Gas Hydrate and Corrosion Inhibitors for Flow Assurance Application: An Experimental and Computational Study

et al. 2022

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“…One of the most well-known kinetic hydrate inhibitors (KHIs) researched and used in the upstream oil and gas industry is poly( N -vinylcaprolactam) (PVCap) as well as VCap copolymers and graft polymers thereof (Figure ). − …”

Section: Introductionmentioning

confidence: 99%

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

et al. 2022

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The deployment of kinetic hydrate inhibitors (KHIs) is a chemical method for the prevention of gas hydrate plugging in gas, condensate, and oil production flow lines. Polymers made using the monomer N-vinylcaprolactam (VCap) are one of the most common KHI classes. Alternative classes of polymers containing caprolactam groups are rare. Here, we present a study on oxyvinylenelactam polymers and copolymers with pendant piperidone or caprolactam groups. Low-molecular-weight homo- and copolymers were obtained. The nonrotating vinylene groups impart rigidity to the polymer backbone. Poly(oxyvinylenecaprolactam) (POVCap) was insoluble in water, but poly(oxyvinylenepiperidone) (POVPip) and OVPip:OVCap copolymers with 60+ mol % OVPip were soluble with low cloud points. KHI screening tests were carried out using the slow constant cooling method in steel rocking cells. POVPip was water soluble with no cloud point up to 95 °C but showed a poor KHI performance. In contrast, OVPip:OVCap copolymers with about 60–70 mol % OVPip were also water soluble and showed a reasonable KHI performance, better than that of poly(N-vinylpyrrolidone) but not as good as that of poly(N-vinylcaprolactam). Surprisingly, several additives known to be good synergists for VCap-based polymers showed negligible synergy or were antagonistic with the 62:38 OVPip:OVCap copolymer with regard to lowering the onset temperature of hydrate formation. However, a blend with hexabutylguanidinium chloride showed a strong effect to delay the onset of rapid hydrate formation.

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“… 14 To prevent wellbore plugging by hydrate regeneration during drilling, Yang et al explored the effect of kinetic hydrate inhibitors (KHI) on hydrate formation and dissociation. 15 − 17 It was found that the decomposition rate of hydrate in the copolymers of polyethylene caprolactam, polyvinylpyrrolidone, polyvinylpyrrolidone, and polyethylene caprolactam was lower than that in fresh water, 15 − 17 but when antifreeze protein chemicals exist in hydrates, the rate of decomposition increases dramatically. 17 Fereidounpour et al found that more filtrate loss of drilling fluid in formation will affect the stability of hydrate.…”

Section: Introductionmentioning

confidence: 99%

“… 15 − 17 It was found that the decomposition rate of hydrate in the copolymers of polyethylene caprolactam, polyvinylpyrrolidone, polyvinylpyrrolidone, and polyethylene caprolactam was lower than that in fresh water, 15 − 17 but when antifreeze protein chemicals exist in hydrates, the rate of decomposition increases dramatically. 17 Fereidounpour et al found that more filtrate loss of drilling fluid in formation will affect the stability of hydrate. Adding polyacrylate in drilling fluid can reduce the filtrate loss of drilling fluid in formation and achieve a better control effect.…”

Section: Introductionmentioning

confidence: 99%

“…In the process of hydrate drilling, changes in factors such as temperature and pressure lead to the decomposition of hydrate in the formation and the regeneration in the wellbore to cause blockage problems, etc., which will affect the extraction of hydrates. − In order to solve the problem of hydrate decomposition caused by drilling fluid invasion, the molecular dynamics simulation and lab experiment were carried out to optimize the NGH decomposition inhibitors, and the mathematical model for evaluating wellbore hydrate stability is established. ,− Based on the device’s accuracy, Zhao et al studied the inhibitory effect of hydrate kinetic inhibitor on hydrate formation, and the optimized drilling fluid has good rheological properties at low temperature, to inhibit hydrate formation and decomposition, which provides drilling fluid technical support for NGH exploitation. , Fan et el studied the decomposition law of NGH and simulated the hydrate saturation in hydrate bearing sediment samples . To prevent wellbore plugging by hydrate regeneration during drilling, Yang et al explored the effect of kinetic hydrate inhibitors (KHI) on hydrate formation and dissociation. − It was found that the decomposition rate of hydrate in the copolymers of polyethylene caprolactam, polyvinylpyrrolidone, polyvinylpyrrolidone, and polyethylene caprolactam was lower than that in fresh water, − but when antifreeze protein chemicals exist in hydrates, the rate of decomposition increases dramatically . Fereidounpour et al found that more filtrate loss of drilling fluid in formation will affect the stability of hydrate.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Different Factors on Methane Hydrate Formation Using a Visual Wellbore Simulator

Wang

Tie

Liu³

et al. 2022

ACS Omega

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During hydrate exploitation, the formation and decomposition of hydrate in the wellbore are affected by many factors such as salinity, temperature, pressure, gas–liquid ratio, and so on. In the drilling process, inhibitors will be added into the drilling fluid, to prevent the formation of hydrates in the wellbore to form blockages. In order to explore the influence of these factors on the formation and decomposition of hydrates, a visual wellbore simulator was used to study the formation, inhibition, and decomposition of hydrates in the wellbore, which affected these factors. First, the accuracy of device was verified, and then the effects of water type, pressure, inhibitor, and gas–liquid ratios (GLR) on methane hydrate (MH) formation were studied. The results show that (1) In fresh water, after the formation of methane hydrate, the pressure of methane gas in the container drops by 6.73 MPa, while in 10% NaCl brine, the pressure of methane gas in the container only drops by 1.24 MPa, since the NaCl is a thermodynamic inhibitor, which inhibits the formation of MH, the amount of dissolved gas in the brine is less, resulting in less pressure drop within the container. (2) Compared with fresh water, the kinetic inhibitor GID3 can better inhibit the generation of MH, but when the dosage of GID3 is 1.0 and 2.0 wt %, the pressure drop of MH in the container is 0.71 and 2.18 MPa, respectively. Therefore, excess inhibitor will reduce its inhibitory effect. (3) When the pressure and GLR increase, the hydrate can absorb more methane after it is formed. However, when there are inhibitors in the fluid, the law of dissolved methane becomes complicated. (4) Appropriate decomposition solution helps to accelerate the decomposition of MH and reduce hydrate blockage in the wellbore during drilling. This article provides a reference for the formation of hydrate in the wellbore during hydrate exploitation.

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Design and development of N-vinylcaprolactam copolymers as kinetic hydrate inhibitors for sour gas environments

Cited by 15 publications

References 27 publications

Development of Highly Efficient Dual-Purpose Gas Hydrate and Corrosion Inhibitors for Flow Assurance Application: An Experimental and Computational Study

Development of Highly Efficient Dual-Purpose Gas Hydrate and Corrosion Inhibitors for Flow Assurance Application: An Experimental and Computational Study

Oxyvinylenelactam Polymers─A New Class of Lactam-Based Kinetic Hydrate Inhibitor Polymers

Effects of Different Factors on Methane Hydrate Formation Using a Visual Wellbore Simulator

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