Method for exploiting natural gas hydrate through parallel horizontal well microwave heating

Abstract

The invention relates to a method for exploiting natural gas hydrate through parallel horizontal well microwave heating and belongs to the technical field of exploitation of natural gas hydrate. The method comprises the following steps: arranging a parallel horizontal well net and performing matched well-completion operation on a target storage by combining geological data, implementing depressurizing production through the horizontal well after well completion until no economic benefit, arranging a ground supply system and an underground microwave heating system on a heat supply well, heatinga natural gas hydrate layer by a microwave heater, and collecting natural gas and produced water from a production well. The parallelly distributed horizontal wells are arranged for the target storage, so that the storage quantity of the available natural gas hydrage is increased; the storage is heated movably by using a continuous oil pipe and the microwave heater; optimal exploitation of the natural gas hydrate storage can be realized by changing the heating position, the heat output power and the water discharging and gas producing speed, the gas production efficiency can be improved and the economic benefit can be increased.

Description

technical field [0001] A method for exploiting natural gas hydrate by microwave heating in parallel horizontal wells belongs to the technical field of natural gas hydrate exploitation, in particular to a method for exploiting natural gas hydrate by comprehensively utilizing a heating method and a depressurization method. Background technique [0002] Natural gas hydrate (NGH) is a non-stoichiometric clathrate compound formed by natural gas and water at a certain low temperature and high pressure, also known as "flammable ice". 1m 3 Natural gas hydrate can contain 164m 3 Methane gas and 0.8m 3 of water. "Combustible ice" is an epigenetic product of natural gas, and its application range is roughly the same as that of natural gas. It is a typical substitute for petroleum. "Combustible ice" is extremely easy to burn. Under the same conditions, the energy generated by the combustion of "combustible ice" is dozens of times higher than that of coal, oil, and natural gas. It is...

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Problems solved by technology

However, the decomposition driving force provided by the depressurization method alone is small, and the decomposition of natural gas hydrate causes the temperature to drop. When the temperature drops below 0°C, it will also cause ice blockage and stagnation of natural gas hydrate decomposition. CN 20111048906.4 discloses a drainage The natural gas hydrate is exploited by depressurization and heating at the same time, which continuously promotes the decomposition of hydrate. The above two methods use the gas escaping after the hydrate is decomposed, and the water falls due to its own weight. The water pump discharges the water out of the natural gas hydrate production well. But in fact, the decomposed gas carries a large amount of water vapor when it escapes, and the escape speed is very slow, and the extraction efficiency is very low

Moreover, in CN 20111048906.4, horizontal wells are used for combustion and heating. It is unsafe to burn and heat in natural gas hydrate exploitation wells. There are combustible gases inside and outside the natural gas hydrate exploitation wells. It is very dangerous to use open flames for direct heating.

In CN 201310398998.0, microwave generators are used to heat and exploit natural gas hydrates, and the decomposition of natural gas hydrates is promoted by heating. However, the use of vertical wells limits the heated volume of heated natural gas hydrates, and it is more convenient to fix the microwave generators on the upper part of the packer. Further limit the heating volume of gas hydrate

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