Unexpected formation of sII methane hydrate in some water-in-oil emulsions: Different reasons for the same phenomenon

Stoporev, Andrey S.; Ogienko, A. G.; Sizikov, Artem A.; Semenov, Anton P.; Копицын, Д. С.; Винокуров, В. А.; Svarovskaya, L. I.; Алтунина, Л. К.; Manakov, Andrey Yu.

doi:10.1016/j.jngse.2018.10.020

Cited by 17 publications

(11 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition to the above-identified phases, although dissociation of C 1 s-I was observed at equilibrium here, some studies have previously shown that s-II methane potentially forms as a stable phase at low temperatures and much higher pressures. − A metastable s-II structure has also been reported at the PT conditions investigated here . Theoretically, methane can enter both the 5 12 and 5 12 6 4 cavities of s-II hydrate ; however, its molecular diameter is insufficient to readily stabilize the large cavity.…”

Section: Results and Discussionsupporting

confidence: 55%

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

2021

View full text Add to dashboard Cite

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...

show abstract

Section: Results and Discussionsupporting

confidence: 55%

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

2021

View full text Add to dashboard Cite

show abstract

“…It should be stressed that some data point to the principal possibility of a change in the hydrate nucleation mechanism with a change in supercooling . The intermediate metastable hydrate phase was registered in the studies of methane hydrate formation from water-in-oil emulsions . At present, we have not got any experimental data that would allow us to give preference to any of the considered versions.…”

Section: Resultsmentioning

confidence: 85%

“…50 The intermediate metastable hydrate phase was registered in the studies of methane hydrate formation from water-in-oil emulsions. 51 At present, we have not got any experimental data that would allow us to give preference to any of the considered versions. The possibility of parallel realization of these mechanisms also cannot be excluded.…”

Section: ■ Experimental Sectionmentioning

confidence: 96%

Effect of Temperature on the Rate of Methane Hydrate Nucleation in Water-in-Crude Oil Emulsion

2019

Self Cite

View full text Add to dashboard Cite

Isothermal nucleation of methane hydrate in the emulsions of water in oil has been studied experimentally at a pressure of 12.5 MPa within the temperature range of −3.0 to −4.9 °C (supercooling 17.8−19.7 °C). It was demonstrated that the experimental survival curves are composed of two regions with different slopes to the time axis. Nucleation rates calculated for initial and final (in parentheses) regions of survival curves turned out to be equal to 0.00065 (0.00055), 0.00036 (0.00017), and 0.00018 (0.00010) s −1 m −2 for temperatures −4.9, −4.0, and −3.0 °C, respectively. The experimental data were extrapolated to the regions of higher and lower supercooling values using a known expression describing the dependence of the nucleation rate on temperature. It may be expected that the information concerning the temperature dependence of hydrate nucleation rates in water−oil systems will be useful to optimize the consumption of kinetic hydrate inhibitors during the development of oil and gas deposits.

show abstract

“…Нефть YuT, из всех исследуемых, проявила положительную реакцию нуклеации и формирования газогидратов. В работе [249] исследованы структуры гидрата метана, полученного из водных эмульсий в маслах четырех типов -н-гептане и н-декане. Для стабилизации эмульсий воды в н-гептане и н-декане использовалось ПАВ Span 80.…”

Section: газовые гидратыunclassified

Новое Суждение О Генезисе Нефти

Симонян¹,

Пирумян²

2021

View full text Add to dashboard Cite

Рассмотрено образование нафтидов в свете абиогенной теории образования нефти. Приведены аргументы против биогенной теории образования нефти. Обсуждаются физико-химические свойства и химический состав нефти. Рассматривается роль азота в генезисе нефти. Показано, что залежи нефтей являются фрактальной, хородинамической и геоинформационной системами. Рассматривается также загрязнение и деградация нефти в гидросфере. Монография может быть рекомендована для специалистов и научных работников в области теории генезиса нефти. Она может быть полезна аспирантам, магистрантам и студентам высших учебных заведений, образовательных учреждений соответствующего профиля

show abstract

Unexpected formation of sII methane hydrate in some water-in-oil emulsions: Different reasons for the same phenomenon

Cited by 17 publications

References 65 publications

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

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

Effect of Temperature on the Rate of Methane Hydrate Nucleation in Water-in-Crude Oil Emulsion

Новое Суждение О Генезисе Нефти

Contact Info

Product

Resources

About