The gas of QHD30 1 is mixed gas and mainly from the coal derived gas from pre Tertiary source rocks.

QHD3 0 1气藏的天然气属多源混合气，主气源为前第三系的煤成气。

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The coal quality of Xiangxi stage is not good and stable but the coal appears dark mud, well develops shale and has high evolution level, which is favorable to create coal derived gas.

香溪煤系煤质较差，极不稳定，但该煤系暗色泥、页岩发育，演化程度较高，有利于形成煤成气。

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There is widespread coal seam of Permo-Carboniferous in Jiyang Depression. The coal has good quality, moderate evolution degree resulted in the foundation of forming medium coal-derived gas reservoir.

济阳坳陷石炭-二叠系煤层分布广泛，煤质优良，演化程度适中，具有形成中型煤成气藏的基础。

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Switching feedstock from naphtha, derived from oil, to ethane, derived from gas, has kept petrochemicals cheap even as oil prices have peaked.

ECONOMIST: Shale gas is giving a big boost to America��s economy

Shale gas derived from sedimentary rocks deep underground needs to be captured, piped and processed before it is consumed.

FORBES: The Other F-Word of Shale Drilling

The reason: Hydrogen engines can run on fuel derived from natural gas more cheaply than other currently available feedstocks.

FORBES: Magazine Article