Influence of Submarine Mud Diapirs（Mud Volcanoes）on Gas Hydrate Accumulation

There are close relationships between the submarine mud diapirs(mud volcanos)and their periphery gas hydrates orebody.The intrusion of gas-bearing fluid in the mud diapirs(mud volcanoes)can change temperature,pressure and geochemical characteristics of GHSZ,and thus should affect the formation and enrichment of gas hydrate.At the same time,as an important and effective migration channel type,the mud diapir(mud volcano)structure exerts methane which can also become an important gas source for gas hydrate.In addition,the mud diapir(mud volcano)have different effects on the formation and stability of the hydrate in the different evolution stages.The migration channel might not extend to the hydrate stability zone in the early stages of mud diapiric formation,resulting in insufficient supply of CH₄.This is conducive to the formation of natural gas hydrates in the middle stage,because of good matching in hydrate metallogenic conditions.The abnormal heat in the hydrate stability zone,caused by high temperature gas-bearing fluid from mud volcano eruption,may lead to the decomposition of hydrates in the late stage.Until the quiet period of mud volcano activity,hydrate can form the reservoir again.There are two models of the formation of gas hydrates within a mud volcano:low-temperature hydrothermal process dominated around the central part of the mud volcano and metasomatic process dominated at the peripherical part of the mud volcano.