Category: Hydrates

Kinetic Inhibitor and Anti-Agglomerators

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A kinetic inhibitor is a polymeric chemical that, when added to a production stream, will not change the hydrate formation temperature but will delay the growth of hydrate crystals. These chemicals are polymericand include N-vinylpyrrolidone (5 ring), saccharides (6 ring}, and Nvinylcaprolactam (7 ring). An anti-agglomerator is an alkyl aromatic sulphonate, a quaternary ammonium salt, …

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Thermodynamic Inhibitor #2

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First the amount of water that will be condensed will be determined from Figure 4-6, assuming the gas is saturated at reservoir conditions. Water content (8,000 psig and 224°F)= 230 Ib/MMscf Water content (4,000 psig and 65°F) = JK) Ib/MMscf Water condensed = 220 Ib/MMscf From. Table 4-1 the hydrate temperature is 74°F. The required …

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Thermodynamic Inhibitors #1

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1. Chemicals can be injected into the production stream to depress the likelihood of significant hydrate formation. 2. A therrnodynamic inhibitor alters the chemical potential of the hydrate phase such that the hydrate formation point is displaced to a lower temperature and/or a higher pressure. 3. Generally, an alcohol or one of the glycols—usually methanol, …

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Temperature Drop Due To Gas Expansion

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Choking, or expansion of gas from a high pressure to a lower pressure, is generally required for control of gas flow rates. Choking is achieved by the use of a choke or a control valve. The pressure drop causes a decrease in the gas temperature, thus hydrates can form at the choke or control valve. …

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Condensation of Water Vapor

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One method of assuring that hydrates do not form is to assure that the amount of water vapor in the gas is always less than the amount required to fully saturate the gas. Typically, but not always, the gas will be saturated with water in the reservoir. As the gas is cooled from reservoir temperature, …

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Determination of Hydrate Formation Temperature or Pressure

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Knowledge of the temperature and pressure of a gas stream at the wellhead is important for determining whether hydrate formation can be expected when the gas is expanded into the flow lines. The temperature at the wellhead can change as the reservoir conditions or production rate changes over the producing life of the well. Thus, …

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Hydrates

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Resembling dirty ice, hydrates consist of a water lattice in which light hydrocarbon molecules are embedded. They are a loosely-linked crystalline chemical compound of hydrocarbon and water called cathrates, a term denoting compounds that may exist in stable form but do not result from true chemical combination of all the molecules involved. Hydrates normally form …

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