Replacing diesel by diesel-natural gas as the fuel for drilling engine unit in natural gas field is one of the effective ways for improving economic benefit and reducing development cost.

天然气气田钻井发动机机组燃料由柴油改为柴油-天然气双燃料，是提高经济效益、降低开发成本的有效途径之一。

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This might be because America uses more oil for each unit of output than other rich countries, so the higher cost of fuel hits growth and thus the dollar harder.

ECONOMIST: Economics focus