Clathrate hydrate formation and subsequent plugging of deep-sea oil and gas pipelines represent a significant bottleneck for deep-sea oil and gas operations. Current methods for hydrate mitigation are expensive and energy intensive, comprising chemical, thermal, or flow management techniques. In this paper, we present an alternate approach of using functionalized coatings to reduce hydrate adhe...

Phenacylmalononitrile 1 reacts with dimethylformamide dimethyl acetal to yield an enaminone which could be readily converted into a pyrrole or an aminopyridazine by treating with ammonium acetate and hydrazine hydrate, respectively. Compound 1 reacted with hydrazine hydrate in ethanol at room temperature to yield the dihydropyridazine 9 as a single product. In refluxing ethanol this product fur...

During Ocean Drilling Program (ODP) Leg 204, we will drill a transect of sites through the gas hydrate stability zone on the southern part of Hydrate Ridge on the Cascadia accretionary margin offshore Oregon. Massive hydrates are present at the seafloor there, and high-resolution threedimensional seismic data indicate a complicated subsurface plumbing system. The transect will cover two distinc...

Uniform manganese hexacyanoferrate hydrate nanocubes are prepared via a simple chemical precipitation method at room temperature. Due to both micro/mesopores of the Prussian blue analogue and nanocubic structures, the manganese hexacyanoferrate hydrate nanocubes allow the efficient charge transfer and mass transport for electrolyte solution and chemical species. Thus, the manganese hexacyanofer...

This paper investigates the kinetics of structure H (sH) formation kinetics above and below the structure I (sI) formation equilibrium curve at temperatures of between 2°C and 6°C. Methane was used as a help gas and methylcyclohexane (MCH) was used as sH former. It was concluded that in the points above the sI formation equilibrium curve, at the first, the sI forms, and then converts to sH be...

The hydrate/methane gas interface is studied by molecular dynamics simulations. Below the hydrate melting temperature a thin liquid film forms with an associated surface charge density and electrostatic potential. The thickness of the thin liquid film, the charge density, and electrostatic potential at the hydrate/gas interface are established at different subcooling temperatures for the first ...

Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract We present a new geologic-time and basin-spatial scale model of the continental margin methane cycle. The model, SpongeBOB, is used to simulate evolution of the carbon cycle in a passive sedimentary continental ...

Direct disposal of liquid CO2 on the ocean floor is one of the approaches considered for sequestering CO2 in order to reduce its concentration in the atmosphere. At oceanic depths deeper than approximately 3000 m, liquid CO2 density is higher than the density of seawater and CO2 is expected to sink and form a pool at the ocean floor. In addition to chemical reactions between CO2 and seawater to...

During Leg 204, we cored and logged nine sites on the Oregon continental margin to determine the distribution and concentration of gas hydrates in an accretionary ridge and adjacent slope basin, investigate the mechanisms that transport methane and other gases into the gas hydrate stability zone (GHSZ), and obtain constraints on physical properties of gas hydrates in situ. A three-dimensional s...

We present an equilibrium model of methane venting through the hydrate stability zone at southern Hydrate Ridge, offshore Oregon. Free gas supplied from below forms hydrate, depletes water, and elevates salinity until pore water is too saline for further hydrate formation. This system self-generates local three-phase equilibrium and allows free gas migration to the seafloor. Log and core data f...