Enhanced oil recovery using nanofluid-assisted thermal methods in low permeability carbonate reservoirs

Project Abstract

This study investigates the integration of nanofluid-assisted thermal methods to enhance oil recovery in low permeability carbonate reservoirs, addressing the dual challenges of limited permeability and strong capillary trapping that impede conventional recovery processes. We deploy a comprehensive experimental and numerical framework to quantify the performance of silica- and alumina-based nanofluids dispersed in thermal solvents (steam and hot water) across a representative carbonate core plug suite with permeability ranging from 0.5 to 5 mD and pore throat distributions typical of tight carbonate formations. Key mechanisms examined include nanofluid-induced alteration of rock–fluid interfacial properties, modification of wettability toward more oil-wet to intermediate wet states, reduction of oil viscosity via thermal effects, and stabilization of displacing fronts through enhanced thermal conductivity and convective transport. The study systematically evaluates nanoparticle concentration, size, zeta potential, and surface functionalization to identify stable dispersions at elevated temperatures and salinities encountered in reservoir conditions. Core flood experiments measure incremental oil recovery, changes in differential pressure, and end-point water cuts under conventional steam, nanofluid-assisted steam, and nanofluid-assisted hot water protocols. Complementary microelectrochemical measurements quantify contact angle dynamics, capillary pressure curves, and interfacial tension reductions to elucidate dominant recovery pathways, including interfacial tension attenuation, contact line pinning decreases, and relative permeability improvements. A multi-physics reservoir simulation model is developed to upscale core-scale observations, incorporating nanoparticle transport, thermal conduction, phase behavior, and wettability alteration. Sensitivity analyses assess the impact of reservoir temperature, salinity, and rock mineralogy (calcite vs. dolomite), as well as particle mobilization risks, potential pore plugging, and economic implications of nanoparticle synthesis and deployment. The results demonstrate that nanofluid-assisted thermal stimulation can achieve statistically significant increases in ultimate oil recovery (0–15 percentage points depending on permeability and mineralogy) compared with traditional thermal methods, with a notable uplift in sweep efficiency attributed to stabilized displacing fronts and favorable wettability shifts. However, optimal performance is contingent on maintaining nanoparticle stability at reservoir conditions and preventing excessive formation damage due to particle deposition. The study proposes a mechanistic framework linking nanofluid properties to macro-scale performance and provides guidelines for selecting nanoparticle types, concentrations, and thermal protocols tailored to low-permeability carbonate reservoirs. The outcomes offer practical pathways for field implementation, including well spacing considerations, thermal budget optimization, and monitoring strategies to mitigate risks, thereby advancing the viability of nanofluid-enhanced thermal EOR as a cost-effective option for mature carbonate fields.

Project Overview

What This Project Is About

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A straightforward exploration of using tiny, engineered particles suspended in a liquid (nanofluids) to help steam or hot fluid push more oil out of rocks with very small pore spaces. The project combines simple cooling/heating methods with nanofluids to improve how easily oil moves through carbonate rocks that typically trap oil.

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The Problem It Addresses

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In low-permeability carbonate rocks, oil is difficult to extract because the rock blocks flow and traditional methods leave a lot of oil behind. Nanofluids can modify the rock surface and reduce oil sticking, while thermal methods provide the heat that makes oil flow more easily. The challenge is to understand if combining these approaches works well and safely in real reservoirs.

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Objectives of the Project

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1. Explain the basic idea of nanofluid-assisted thermal EOR in simple terms.
2. Assess how different nanofluids affect oil mobility in carbonate rocks.
3. Evaluate the impact of temperature on oil recovery with nanofluids.
4. Identify practical limitations and safety considerations for field use.
5. Suggest a feasible experimental or simulation plan for further study.

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What You Will Do Step by Step

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1) Learn the basic concepts of oil recovery and why carbonate rocks are challenging. 2) Review simple literature findings on nanofluids and thermal methods. 3) Design a small-scale experiment or computer model to test oil flow with nanofluids at various temperatures. 4) Collect data on oil recovery under different conditions. 5) Analyze results to see if improvements are consistent and explain why. 6) Discuss practical steps before any real-world testing.

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Expected Outcome

Clear, easy-to-understand conclusions on whether nanofluid-assisted thermal methods can boost oil recovery in low-permeability carbonate rocks, including potential benefits, limits, and the next steps for lab or field testing.