The answer: wells that drill vertically down to the shale bed, then make a gradual 90-degree horizontal turn through the shale deposit.

目前，科学家提出了解决方案——先垂直钻探至页岩床位置，然后以90度水平地钻探页岩沉积层。

youdao

The fourth oil shale bed developed in lacustrine bog distributes unsteadily with small thickness. It is belong to the oil shale of middle ash and oil yield.

形成于湖沼相的油四层厚度较小，平面上分布不稳定，含油率较高，属中灰分中含油率的油页岩。

youdao

Unconventional sources of oil and gas that are set for further exploitation include Canada's tar sands, shale and coal-bed methane deposits around the world.

ECONOMIST: Drilling on Wall Street | The

"As we can see from the experience in the US, the exploration of shale gas and coal-bed methane has the potential to raise billions of pounds, resulting in reduced energy bills, " he said.

BBC: Scottish Conservatives back greater energy mix

The Energy Information Administration (EIA) puts it at around 37tcm of recoverable reserves, two-thirds of which is shale gas and the rest tight gas and coal-bed methane.

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