Unconventional oil and gas: Techniques

Fracking, steam floods, oil sands mines and frozen methane

What this tab covers The methods used to capture this energy: how each works, and how they compare on efficiency, cost, life-cycle emissions, maturity and scale.

Five techniques tap oil and gas that will not flow naturally. Fracturing alone supplies about 64% of US crude and 78% of US dry gas (2023).

Comparison

Method	Efficiency	Cost	Life-cycle emissions	Maturity	Scale
Hydraulic fracturing and horizontal drilling¹²³¹⁰¹¹²¹⁷⁸	Under 10% of oil, 15-30% of gas in place	Breakeven about USD 45 per barrel (Rystad, 2024); USD 65 average for a new US well (2025)	Gas power about 490 g CO2e/kWh (IPCC median), more with methane leaks	mature	US tight oil 8.32 million barrels per day; shale gas 37.87 trillion cubic feet (2023)
Enhanced oil recovery (water, CO2, steam)²²⁴²⁵	Gas injection adds 10-15 percentage points of oil in place	Not reported in our sources	Steam burns gas; US CO2 floods inject 300-600 kg CO2 per barrel, part stored	mature	About 375 projects, just over 2 million barrels per day (2017)
Oil sands mining and SAGD³¹⁰⁴¹²	Over 90% (mining plant), 40-60% (SAGD) of bitumen	Breakeven about USD 57 per barrel, up to USD 75 (2024)	Energy-intensive: point-of-use energy return about 3	mature	Alberta 2025: 3.72 million barrels per day, 52% in situ
Coalbed methane⁹	Not reported	Not reported	As other natural gas	mature	About 2% of US dry gas (2022)
Methane hydrate pilots¹⁵	Not established	Not commercial	Not assessed in our sources	pilot	Largest test: 861,400 m3 of gas, South China Sea (2019-2020)

Fracking wells are quick to drill but recover little of the resource and must be constantly replaced. Oil sands mining recovers almost all the bitumen in the ore but is capital- and energy-intensive, with the highest costs per barrel. Coalbed methane is a niche and hydrates are experimental. Shale gas has the best energy return; oil sands and thermal recovery the worst.

How each method works

Hydraulic fracturing and horizontal drilling

A well is drilled into shale and turned to run horizontally for kilometres. Water, sand and chemicals pumped in at high pressure crack the rock, and the sand props the cracks open. Output falls steeply within a few years, so drilling must continue.¹²³¹⁰¹¹²¹⁷⁸

Enhanced oil recovery (water, CO2, steam)

After waterflooding, operators inject CO₂ or hydrocarbon gas that mixes with the oil, steam that thins heavy oil, or chemicals that free oil from rock.²²⁴²⁵

Oil sands mining and SAGD

Shallow ore is dug and washed with hot water to separate bitumen. Deeper deposits use SAGD: steam from one horizontal well heats the bitumen, which drains to a second well below.³¹⁰⁴¹²

Coalbed methane

Wells pump water out of unmined coal seams; lower pressure lets adsorbed methane flow to the well.⁹

Methane hydrate pilots

Lowering well pressure makes ice-like methane hydrate in seabed sands break down into gas and water.¹⁵

Sources

Technology 101: EOR methods for shale and tight formations Journal of Petroleum Technology (SPE), 2016
Increasing Hydrocarbon Recovery Factors (Zitha, Felder, Zornes, Brown and Mohanty) Society of Petroleum Engineers, 2011
Alberta's Surface Mineable Oil Sands Projects: Recovery Factors That Are Far From Conventional (Freeborn, GLJ) BOE Report, 2016
Energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010 (Brandt, Englander and Bharadwaj, Energy 55: 693-702, doi:10.1016/j.energy.2013.03.080) Stanford Environmental Assessment and Optimization Group, 2013
FAQ: How much shale (tight) oil is produced in the United States? US Energy Information Administration, 2024
FAQ: How much shale gas is produced in the United States? US Energy Information Administration, 2024
Natural gas explained: Where our natural gas comes from US Energy Information Administration, 2024
Rystad Energy: Cost of new upstream oil projects rises further Oil & Gas Journal, 2024
Dallas Fed Energy Survey, First Quarter 2025 Federal Reserve Bank of Dallas, 2025
ST98: Alberta Energy Outlook, Crude bitumen production Alberta Energy Regulator, 2026
Gas Hydrate Energy Research: 2024 Update US Geological Survey, 2024
Climate Change 2014: Mitigation of Climate Change, Annex III: Technology-specific cost and performance parameters (Table A.III.2, life-cycle emissions) IPCC Working Group III, 2014
EIA/ARI World Shale Gas and Shale Oil Resource Assessment (Kuuskraa, EIA Energy Conference presentation) US Energy Information Administration / Advanced Resources International, 2013
Whatever happened to enhanced oil recovery? International Energy Agency, 2018
Can CO2-EOR really provide carbon-negative oil? International Energy Agency, 2019