Oil and gas are now being extracted in large quantities directly from organic-rich
shales and other sedimentary rocks with low permeability. Which of the following
technological advances have made this possible?
1) seismic surveys & deep-ocean drilling
2) horizontal drilling & hydraulic fracturing
3) hydraulic fracturing & deep-ocean drilling
4) high pressure blowout preventers & deep-ocean drilling
5) seismic surveys & high pressure blowout preventers