In situ measurement of fluid flow and signatures of seep activity at marine seep sites
海底冷泉流体渗漏的原位观测技术及冷泉活动特征

Cold seepage is a widely observed phenomenon in marine environment worldwide. This paper focuses on a review of the in situ measurement of cold seep and its results of several typical active cold seeps in the world. Seepage activity is generally associated with the seafloor fractures and faults. Mud volcanes, pockmarks, hydrate, cold seep communities, and seep carbonate are common at the seep sites. Basically, there are two types of fluids, liquid and gas, and two modes of fluid flow, upward and downward flow at seep sites. The flux of fluid changes greatly, which is usually controlled by the geological settings. Hydrocarbon seepage erupts along a fault to seabed as bubbles and oil drops, releasing large amount of hydrocarbons. This process is controlled mainly by swell, hydrostatic pressure, and fracture pressure and so on. Seepage activity is a complicated hydrogeology process that is mainly correlated with hydrate formation and decomposition related to the filling and emptying of gas reservoir, destruction of deep oil and gas reservoir, and submarine environmental change.