The Development of Natural Gas Hydrate Exploitation Technology From Perspective of Patents
Haibo Wang, Le Zhang, Jiayuan He, Tong Zhou
Abstract
As an unconventional energy source, natural gas hydrate is a polyhedral cage crystal formed by hydrogen bonding between methane and a small amount of non-hydrocarbon gases and water molecules under high pressure and low temperature Natural gas hydrates are widely distributed in permafrost and deep-water areas. The main methods of mining natural gas hydrate are depressurization method, heating method, inhibitor method, CO 2 replacement method and solid exploitation method. The depressurization method and heating method are commonly used in the production of natural gas hydrate. The basic principle is to change the temperature and pressure of the environment where the hydrate is located, destroy the hydrate equilibrium state, and promote the decomposition of the hydrate into natural gas and water. Natural gas hydrate has attracted extensive attention of the state and industry due to its huge resource potential. It is known as one of the most promising strategic alternative energy sources for commercial development in the 21st century More than 30 countries around the world have successively formulated national key development strategies for natural gas hydrate and actively carried out hydrate exploration and development research Five countries including Japan, the United States, Canada, South Korea and China have carried out gas hydrate production (Le and He, 2021). On 17 February2020, the second round of pilot production was carried out in the water depth of 1,225 m. After 1 month of pilot production, the total gas production was 861400 m 3 and the average daily gas production was 28700 m 3 , which was 2.8 times of the total gas production in the first round of 60 days China has become the world's first country to use horizontal well drilling technology to test natural gas hydrate in the sea area (Ye and Qin, 2020). However, due to immature development technology, high cost, and environmental concerns, commercial exploitation of natural gas hydrate has not yet been realized.