Mature fields still hold a lot of oil. Enhanced oil recovery techniques help move that trapped oil by changing fluid properties, pressure, or flow paths after primary and secondary recovery have done their part. In plain terms: heat it, thin it, push it, or tune the rock–fluid system so more barrels flow. Enhanced oil recovery techniques typically add 10–30 percentage points to recovery factors depending on geology, fluids, and execution. This guide explains the major enhanced oil recovery techniques, recent upgrades that cut emissions, and where to start if you manage a brownfield.
What enhanced oil recovery techniques include
At a high level, enhanced oil recovery techniques fall into three classic families: thermal, gas, and chemical, plus newer hybrids. U.S. DOE’s primer remains the clearest baseline: thermal (steam/in‑situ combustion), gas (CO₂, N₂, hydrocarbon), and chemical (polymer, surfactant, ASP).
- Thermal lowers viscosity so heavy oil flows.
- Gas adds pressure or miscibility to swell/thin oil.
- Chemical improves sweep and interfacial behavior.
A 2024 review adds emerging options such as nanotechnology and microbial approaches, which aim to boost viscosity control, wettability shifts, and stability under salinity/temperature stress. [Enhanced O…d Advances]
Gas‑injection enhanced oil recovery techniques
CO₂ injection and WAG
CO₂ dissolves into crude, swelling oil and lowering viscosity; miscible floods can unlock large incremental barrels. In the U.S., gas injection already dominates EOR volumes; DOE’s overview captures the “why.” Enhanced oil recovery techniques like WAG (water‑alternating‑gas) or SWAG temper channeling and improve sweep in layered reservoirs.
CO₂‑EOR can both produce and store CO₂. Late‑life work shows that swapping part of the steam input with CO₂ raises thermal efficiency and can cut modeled emissions by >50% through steam savings and in‑reservoir storage.
Chemical enhanced oil recovery techniques
Polymers thicken floodwater to fix unfavorable mobility ratios and push oil from high‑perm thief zones into tighter rock. Field economics are attractive: industry reports show polymer often adds barrels at low incremental cost, with modular surface packages. Enhanced oil recovery techniques based on polymer also reduce water handling and energy per barrel, lowering carbon intensity.
Surfactant and ASP flooding
Surfactants lower interfacial tension to mobilize residual oil; ASP combines alkali, surfactant, and polymer for synergistic effects in certain sandstones and carbonates. Reviews in 2024–2025 map where ASP is realistic given salinity, temperature, and crude composition.
Thermal enhanced oil recovery techniques
Steam flooding with gas or foam assists
Thermal methods dominate heavy‑oil plays, but heat loss can erode economics and raise emissions. Upgrades focus on adding non‑condensable gas (NCG/CO₂) during late life, or foam assists to reduce channeling and retain heat:
- Modeling: replacing part of late‑stage steam with CO₂ improved oil‑to‑steam ratio and showed >50% emissions reductions potential.
- Experiments: flue‑gas foam‑assisted steam flooding improved recovery vs. steam‑only and retained gas to curb condensation losses.
Low‑salinity waterflooding
Low salinity water flooding shifts wettability toward water‑wet conditions in many rocks. New work helps choose the right geochemical mechanism and modeling approach; MIE (multi‑ion exchange) with sulfate as a key interpolation factor often matches lab results best. Mineralogy matters: mixed limestone/dolomite systems can favor certain dilutions. Secondary‑mode LSWF can outperform tertiary in low‑perm sandstones.
Designing a practical EOR plan in 90 days
Week 0–2: Decision screen
Reservoir screen: API, viscosity, temp, pressure, salinity, permeability contrasts; shortlist enhanced oil recovery techniques that fit fluids and rock. Use DOE taxonomy as a first pass.
Week 3–6: Bench tests & modeling
Brine/crude/rock tests: IFT, contact angles, polymer rheology vs. salinity/temperature; simple corefloods for mobility control and wettability trends.
Week 7–10: Surface package & MOC
For polymer: modular skid sizing, produced‑water impacts, chemical logistics. For gas: CO₂ sourcing, compression, WAG cycles.
Week 11–13: Pilot plan
- Pattern selection (heterogeneity, injectivity, offset risks).
- Acceptance criteria: incremental oil, WOR trend, injectivity, pattern interference.
- Roll‑forward math to full field.
Emissions and ESG
Not all recovery techniques are equal on carbon. Polymer floods cut produced‑water volumes and pumping energy; LCA shows sizable CO₂ reductions versus waterflood baselines. CO₂‑EOR can store CO₂ while producing, and late‑life heavy‑oil operations can improve OSR by substituting CO₂ for part of the steam requirement. Capture these gains with metering and MRV so investors can see the drop in carbon intensity per barrel.
What competitors cover, and how to go beyond them
Most top results explain categories and list pros/cons. To outrank, add: (1) emissions math per technique, (2) pilot checklists and acceptance criteria, (3) digital supervision of mobility ratio and conformance, (4) case‑grade numbers. Use that lens across enhanced oil recovery techniques for clarity and usefulness.
Conclusion
You improve mature‑field outcomes when you pick and tune recovery techniques to your rock, fluids, and surface limits. Start with a clean screen, run tight bench tests, and pilot with disciplined acceptance criteria. Combine polymer or CO₂ with basic real‑time monitoring to capture barrels and lower emissions intensity. For further reading, visit The Universal Insights for more blogs.
