China and Russia Identify Key to Unlocking Massive Natural Gas Reserves in "Combustible Ice"
Scientists from Russia and China have jointly uncovered the fracturing mechanism of rock formations containing "combustible ice." The findings are expected to reduce the risk of accidents during natural gas extraction. The collaborative research was conducted by Perm State University and China University of Petroleum.
"Combustible ice" may sound unfamiliar, but its principle is straightforward: water molecules form crystalline structures that trap gases—primarily methane—within their lattice. These substances resemble ice in appearance and are typically preserved under low-temperature, high-pressure conditions. Despite their vast reserves, extraction remains highly challenging.
When environmental conditions shift, the "ice" begins to decompose, causing surrounding rock layers to soften. This poses significant risks for extractors: wellbore collapse and gas leakage are potential outcomes. Therefore, merely identifying reservoirs is insufficient; understanding how rock formations behave during drilling and extraction is essential.
Researchers prepared eight samples using quartz sand and natural gas hydrates—commonly known as "combustible ice." Half of the samples contained approximately 80% hydrate, while the other half contained about 40%. Under simulated subsurface pressure conditions, the samples were compressed and subjected to high-pressure water injection.
The injected water induced fractures, and sensors detected faint cracking sounds. These measurements enabled researchers to monitor the fracture development process. Results indicated that samples with higher concentrations of "combustible ice" fractured more easily and rapidly.
The shape of the cracks also varied depending on the magnitude of compression. Some fractures ran nearly straight, while others followed winding, branching paths. Such complex networks can provide additional pathways for gas release. However, precise control is critical: beneficial fractures must not evolve into structural collapse.
These data now serve as a basis for calculating optimal extraction pressures. While scientists have not yet announced a mature method for large-scale natural gas extraction from "combustible ice," this study represents a significant step forward.
Original source: toutiao.com/article/1881652774899724/
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