Variable-frequency vibration exploitation method of offshore gas hydrate

Abstract

The invention discloses a variable-frequency vibration exploitation method of offshore gas hydrate and belongs to the technical field of offshore resource exploitation. The variable-frequency vibration exploitation method includes steps of drilling a methane gas hydrate reservoir layer via an offshore drilling rig, releasing stress energy to promote decomposing of gas hydrate by a vibrator at the top of a drill pipe, gathering the decomposed methane gas around drilling holes and enabling the methane gas to move upwards along the drill holes by means of natural pressure difference of the hydrate decomposing area and the drill holes; controlling rising speed of the methane gas, and collecting the methane gas from the drill holes to the drilling rig by a collector and storing. By adjusting energy of the vibrator, different frequencies of excitation energy are applied according to different saturation degrees of methane reservoir layers, the vibration energy can be adjusted according to decomposition of the methane gas, and decomposing speed and range of the gas hydrate can be effectively controlled; disasters such as unordered seabed landslide due to changes of depositional conditions are avoided.

Description

technical field [0001] The invention belongs to the technical field of marine resource exploitation, and in particular relates to a method for exploiting marine gas hydrate with frequency conversion vibration. Background technique [0002] The main component of marine gas hydrate is methane, which is an energy mineral formed by the combination of methane and water molecules in seabed sediments under low temperature and high pressure environment. It has the characteristics of high energy density, huge resources, and cleanliness. It is a new type of energy in the 21st century, which is of great significance in resource development, environmental protection and global climate change. The formation and dissociation of marine gas hydrates is a complex dynamic process, and its constraints are changes in temperature and pressure conditions, that is, the organic combination of low temperature and high pressure, and each lacks obvious specific boundary conditions. Several common met...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the difficulty in controlling the process and scope of solid gas hydrate decomposition in the existing marine gas hydrate mining method, which leads to gas hydrate leakage and seabed landslides, so it provides a method that can avoid the seabed after methane is released. Marine gas hydrate frequency conversion vibration mining method that causes disasters such as submarine landslides due to changes in deposition conditions