Gas hydrate blockage removal using chemical injection in vertical pipes

Aminnaji, Morteza; Tohidi, Bahman; Burgass, Rhoderick William

doi:10.1016/j.jngse.2017.02.003

Cited by 43 publications

(13 citation statements)

References 5 publications

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“…When it comes to the operation of gas fields, hydrate formation occurs in the presence of thermodynamic inhibitors such as MEG or MeOH in the presence of salts, i.e., NaCl solutions. Morphology of hydrate formation in the presence of thermodynamic inhibitors has been studied generally on individual inhibitor systems. ,, There are practically no observations of methane hydrate formation in MEG/NaCl or MeOH/NaCl solutions. The objective of this study is to investigate the morphology of methane hydrate crystals in the presence of both thermodynamic inhibitors (MeOH or MEG) and salt.…”

Section: Introductionmentioning

confidence: 99%

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

Kim

Veluswamy

Seo

et al. 2018

Crystal Growth & Design

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In this study, we investigate the morphology of methane hydrate formation and growth in the presence of wellknown thermodynamic inhibitors, monoethylene glycol (MEG) and methanol (MeOH) in a quiescent system. Morphology changes observed during the growth of methane hydrate while employing 5 wt % MEG and MeOH solutions in the presence and absence of NaCl are presented. When 5 wt % of MEG or MeOH was present in an aqueous solution individually, hydrate grew predominantly within the bulk solution featuring a "ridge"-shaped formation above the interface. In the presence of 3.5 wt % NaCl, an enhanced inhibition was observed for methane hydrates formed from 5 wt % MEG solution with limited hydrate growth in the bulk solution and above the gas-liquid interface. In contrast, 5 wt % MeOH solution in the presence of 3.5 wt % NaCl resulted in an increased hydrate growth in bulk (compared to the system without NaCl) and on the reactor wall above the gas−liquid interface, implying a weak promotion rather than the inhibition. Further, the effect of subcooling (ΔT) on the morphology of methane hydrates in the presence of MeOH/NaCl and MEG/NaCl was examined.

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Section: Introductionmentioning

confidence: 99%

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

Kim

Veluswamy

Seo

et al. 2018

Crystal Growth & Design

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“…The simplified cubic plus association (sCPA) equation of state (EoS) option was used. The estimated percentage of water converted to hydrate, as shown in some figures, was calculated using a modified version of that described in Aminnaji et al 49 from the change in pressure due to hydrate formation; this being assumed as primarily resulting from free gas consumption. Here, gas compressibility (z) and water volume expansion to hydrate were additionally accounted for.…”

Section: Experimental Methods and Materialsmentioning

confidence: 99%

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

2021

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Traditionally, it is commonly assumed that a single gas hydrate (or clathrate hydrate) structure/phase is formed in natural gas systemse.g., "s-II natural gas (NG) hydrates" or "s-I methane hydrates"based on that which is understood to be the most thermodynamically stable at incipient phase boundary conditions. This applies with respect to both studies of hydrates in natural sediments, and in the case of hydrocarbon production operations, including the testing of low-dosage hydrate inhibitors (LDHIs). Here, we present the results of experimental studies of simple propane (C 3 ), binary methane−propane (C 1 −C 3 ), and ternary methane−ethane−propane (C 1 −C 2 −C 3 ) hydrate systems, aimed at investigating phase behavior at higher subcoolings where significant water conversions to clathratesand associated gas fractionationmight be expected to result in the formation of more than one hydrate structure. Measurements were made by means of established, reliable, isochoric equilibrium step-heating/cooling approaches. In the single guest propane system, pressure−temperature (PT) conditions follow the gas hydrate phase boundary, in agreement with the univariant hydrate + gas + water (H + G + W) equilibrium. By contrast, binary and ternary mixes clearly show PT behavior consistent with the growth of at least two and four hydrate phases, respectively, with these forming sequentially on cooling, and dissociating in the corresponding reverse order upon heating. In-house hydrate model (HydraFLASH) predictions support experimental observations, pointing to processes being gas fractionation driven; the mixed C 3 −C 1 or C 3 −C 2 −C 1 s-II type hydrates formed first close to the phase boundary preferentially incorporating the most strongly clathrate cage (5 12 6 4 ) stabilizing propane, making the remaining gas leaner. Once C 3 is largely consumed, trends agree with less stable C 2 −C 1 structures (s-II followed by s-I) then growing (where ethane is present), with this, like C 3 uptake, making remaining free gas increasingly of almost pure C 1 . This ultimately drives systems toward the final simple, single guest C 1 s-I clathrate formation as the well-established univariant phase boundary for this structure is reached. As observed phase behavior arises because of gas fractionation, it can be expected to occur during hydrate formation in all mixed gas systems of relatively fixed composition (at constant volume or pressure). The findings highlight that care should be taken in the application of isochoric methods to multicomponent gas systems, given the potential for numerous (rather than just one) clear changes in heating curve slopes as different hydrate structures form/dissociate. In addition, results show that extending equilibrium steps well into the hydrate region can reveal important information on clathrate phase behavior with potentially significant implications for issues such as gas production from hydrates in sediments, hydrate technologies for gas capture/separation/storage in the energy industry, and flow assuranc...

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“…Massive energy consumption inhibitor injection [4] Inject CH 3 OH、CaCl and other substances into the natural gas hydrate Less equipment investment; Low energy consumption Great environmental impact; Limited decomposition capacity CO 2 replacement [5] Inject CO2 to replace methane in natural gas hydrate…”

Section: Measures Advantages Disadvantagesmentioning

confidence: 99%

Study on hydrocyclone used for natural gas hydrate mining

Chang

Wang

2020

E3S Web Conf.

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Nowadays, energy shortages and global environmental pollution problems are becoming increasingly prominent, and the exploration of clean and renewable energy has become an important direction of energy research. Natural gas hydrates have become the most promising alternative energy source in the future due to its advantages of high calorific value, small environmental hazards and abundant mineral deposits. About 99% of natural gas hydrates are stored in the seabed formation. In 2014, China proposed solid-state fluidized mining technology for marine natural gas hydrates. One of its key technologies is to remove sand from hydrates in real time and backfill the sand on the seabed. Therefore, a downhole axial hydrocyclone suitable for the exploitation of marine natural gas hydrates is proposed in this paper. The purpose of this study is to achieve real-time sand removal and backfilling of downhole hydrate mixed slurry, reduce the sand content of produced fluid, protect the seabed stratum structure, and at the same time reduce the energy consumption of pipeline transportation. In this study, the experimental method was used to evaluate the separation performance of the cyclone with a nominal diameter of 100 mm under different working conditions.

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Gas hydrate blockage removal using chemical injection in vertical pipes

Cited by 43 publications

References 5 publications

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

Experimental Measurement of Multiple Hydrate Structure Formation in Binary and Ternary Natural Gas Analogue Systems by Isochoric Equilibrium Methods

Study on hydrocyclone used for natural gas hydrate mining

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