دانلود کتاب تضمین جریان – جلد دوم – سری مدیریت شیمی نفت و گاز

First discovered in 1810, gas hydrates are nonstoichiometric crystalline icelike compounds composed of cooperative hydrogen-bonded water molecules forming nano-scale clathrate cage structures that trap smaller guest molecules. They can form naturally under certain conditions of pressure and temperature within a gas/water mixture. Gas hydrates attract interest from many different fields of study since naturally occurring gas hydrates have been found in diverse conditions and locations, such as arctic permafrost, under the ocean floor, and even suspected on some other bodies in the solar system. Gas hydrates can also form during extraction/transport/process of oil/gas under certain pressure/temperature conditions in presence of water, which can cause production interruption, asset integrity, and safety issues. This type of hydrates will be the focus of this chapter, which covers the fundamentals of gas hydrates and hydrate management strategies in oil/gas industry. Hydrates in nature play a big role in the global carbon and climate cycles and are also considered an alternative source of energy. Once a hydrate plug is formed in the oil/gas production system, it can be very challenging to remediate, especially in deepwater, and can bear significant implications in terms of deferred production, asset integrity, and safety. The formation of hydrate can result in significant production loss. Depending on the options available, remediating hydrate can take a long time, during which the production can be either compromised or completely stopped. For example, a hydrate plug in a deepwater flowline took a year to dissociate and the production was lost during the entire time. In case the hydrate plug is formed in gas export line, the entire production of a platform will be shut down in that scenario. Formation of hydrate is also integrity and safety concern. The risks are mainly related to the remediation process. Due to the large amount of gas release when dissociated, adding heat to dissociate hydrate in confined volume can create extremely high pressure that can burst the containment barrier, which have resulted in fatalities. A recent study even indicated that gas hydrate may be one of the root causes for the Deepwater Horizon explosion. When depressurization is applied to dissociate a hydrate plug, the hydrate plug can be suddenly dislodged and pushed toward to the low-pressure end at high speed. The resulting hydrate projectile has caused asset damage in the past.