Fracking-the high-pressure injection of water, chemicals and sand into shale deposits to release the gas and oil trapped within the rock-in recent years has been combined with horizontal drilling ...

Oil is trapped within that rock in tiny pores - the "reservoir" is more like a hard, wet sponge than an underground lake. To force oil out of the pores, the acoustic waves produce micro fractures ...

but we’d say it reminds us more of an oil spill than a rainbow. Its variety of colors is the result of the presence of inclusions, tiny particles of material that became trapped within the ...

shale oil is trapped within the tiny pores of shale rock. This makes it more difficult and expensive to extract. For a long time, shale oil was considered to have no economic value for extraction.