In 2008, practical samples of natural gas hydrate(NGH)were drilled out in the frozen soil region of the Qilian Mountain in the Qinghai-Tibetan Plateau for the first time in China, and since then the Sanlutian Well Field in the Muli Coalfield becomes a research focus. But the lack of studies of the controlling factors of the NGH's formation and storage and the NGH's distribution hinders the NGH's exploration and exploitation. An analysis of the materials taken out of the NGH's boreholes in the Sanlutian Well Field and the well field's structural framework reveals the NGH's formation process in the study area, including the structure's role in controlling the NGH reservoir forming. It is concluded that: 1) a reservoir of the NGH is formed by hydrocarbon gases first, and then the NGH enters the temperature-pressure stable zone with Qinghai-Tibetan Plateau's rapid uplift to form a hydrate reservoir; 2) the study area's structure features of partition and zoning control the NGH's flat spreading; the structural movement decides the middle Jurassic coal measures' sedimentation, the hydrocarbon generation and the temperature-pressure stable zone's formation; the structural shape provides the channels, the cap rocks and the storage areas for hydrocarbon gases' enrichment; the later tectonism destroys the earlier gas reservoir and the NGH reservoir.

Sanlutian Well Field  /  natural gas hydrate  /  structural control  /  structural-strata combines