Flow assurance refers to guarantee of flow of a hydrocarbon stream in a pipeline from reservoir to point of sale. In hydrocarbon flow in a pipeline, pipeline blockage may occur due to formation of various solids like gas hydrates, wax, asphaltene, scale and naphthenates. These blockages are often difficult to remove resulting in loss of time, manpower and production. In deep water oil exploration, multiphase flow of crude oil, produced water and natural gas at low temperatures and high pressures takes place in the string of pipes connecting the Blowout preventer (BOP) at sea bottom to oil collection vessel at sea level. As suitable temperature and pressure conditions exist in the crude oil pipeline, so gas hydrates may form in the pipeline due to interaction of natural gas and water. The formation of gas hydrates result in difficult to remove blockage in the pipeline leading to loss of time, manpower and production. In case formation of gas hydrates in the subsea crude oil pipelines can be predicted then these losses can be avoided by taking preventive measures to avoid formation of gas hydrates. These preventive measures can include electrical heating of pipeline, heating of pipeline through a pipe in pipe heating system or injection of hydrate inhibitors like methanol and glycols. However, as temperature and pressure of multiphase mixture of crude oil, produced water and natural gas varies throughout the subsea pipeline so conditions suitable for formation of gas hydrates exist only in a section of the subsea pipeline. In case this section of subsea pipeline prone to formation of gas hydrates could be accurately predicted then the costly preventive measures to avoid formation of gas hydrates could be applied just to this section of pipeline rather than complete pipeline. This will result in flow assurance with considerable saving in cost.
For flow assurance in a pipeline through which hydrocarbon mixture is flowing, the temperature and pressure conditions suitable for formation of gas hydrates, wax and other solids which can block the pipeline must be known. Also temperature and pressure conditions throughout the pipe length should also be known. The temperature and pressure conditions existing in the pipeline not matching with those suitable for formation of blockages results in flow assurance.
HYD-PREDIC is a flow assurance software to predict the section of a subsea vertical crude oil pipeline prone to formation of gas hydrates. More information regarding flow assurance software, HYD-PREDIC can be gathered from HYD-PREDIC webpage. Results of HYD-PREDIC could be requested through http://www.eq-comp.com/pipeline-hydrate-prediction-calculator-software/ webpage