In this work we investigated the behavior of methane hydrates dispersed in crude oils from different fields at temperatures below 0°C. In case of crude oil emulsion the size of water droplets is in the range of 50÷100μm. The size of hydrate particles formed from droplets is the same. The self-preservation is not expected in this field. However, the self-preservation of hydrates with the size of...

The presence of structure H (sH) methane hydrate in natural environments, in addition to the well-known structure-I (sI) and II (sII) hydrates, has recently been documented. Methane in the presence of condensates (C5-C7) forms sH hydrate at lower pressure than the sI hydrate. Thus, the occurrence of sH methane hydrate is likely to have both beneficial and negative practical implications. On the...

The accumulation of gas hydrates in marine sediments is essentially controlled by the accumulation of particulate organic carbon (POC) which is microbially converted into methane, the thickness of the gas hydrate stability zone (GHSZ) where methane can be trapped, the sedimentation rate (SR) that controls the time that POC and the generated methane stays within the GHSZ, and the delivery of met...

Iron oxide (Fe2O3) is widely used as a catalyst, pigment and gas sensitive material.  In this article, α-Fe2O3 nano-rods were first synthesized via a simple chemical method using iron(III) nitrate 9- hydrate (Fe(NO3)3.9H2O) as precursor. XRD pattern showed that the iron oxide nanoparticles exhibited alpha-Fe2O3 (hematite) structure in nanocrystals. The single-phase α- Fe2O3 nano-rods were prepa...

Antifreeze proteins (AFPs) prevent ice growth by binding to a specific ice plane. Some AFPs have been found to inhibit the formation of gas hydrates which are a serious safety and operational challenge for the oil and gas industry. Molecular dynamics simulations are used to determine the mechanism of action of the winter flounder AFP (wf-AFP) in inhibiting methane hydrate growth. The wf-AFP ads...

A number of laboratory experiments have investigated the rates and mechanisms of hydrate formation in coarse-grain porous media. They have shown the importance of initial water saturation and salinity on forming methane hydrates in mostly excess gas systems. Many of these experiments were conducted in a sample holder fitted within a MRI instrument that allowed for a unique method of monitoring ...

Gas hydrates were first discovered by Sir HumphryDavy in 1810 [1]. Clathratehydrates are crystalline compounds, formed by the smaller molecules (guest), entrapped within the cavities of a rigid “cage-like” lattice of water molecules (host) at low temperature (typically less than 300K) and high pressure (typically more than 0.6MPa) conditions [2]. The small molecules of gasses, such as methane (...

Based on driving force for crystallization of one-component gas hydrate, in this report an expression for the supersaturation for crystallization of multicomponent gas hydrate is derived. Expressions for the supersaturation are obtained in isothermal and isobaric regimes. The results obtained are applied to the crystallization of hydrates of mixtures of methane plus ethane and can apply to ...

Gas clathrate hydrates were first identified in 1810 by Sir Humphrey Davy. However, it is believed that other scientists, including Priestley, may have observed their existence before this date. They are solid crystalline inclusion compounds consisting of polyhedral water cavities which enclathrate small gas molecules. Natural gas hydrates are important industrially because the occurrence of th...

A simple prognostic tool for gas hydrate (GH) quantification in marine sediments is presented based on a diagenetic transport-reaction model approach. One of the most crucial factors for the application of diagenetic models is the accurate formulation of microbial degradation rates of particulate organic carbon (POC) and the coupled formation of biogenic methane. Wallmann et al. (2006) suggeste...