Nanometals are useful for improving the effectiveness of in situ combustion-enhanced oil recovery. The effects of five different transition-metal nanoparticles on Colombian, Venezuelan, and Mexican crude oil samples are investigated. Experiments are used to measure the change in burning characteristics with additives at two different length scales. At the smallscale, it is shown that select nanoparticles decrease the apparent activation energy for combustion, change the gateway reaction (i.e., the reaction with the greatest activation energy), make combustion fuel more reactive, increase the fuel quality, and alter the low-temperature oxidation products. During reactive flow, the improvements as mentioned above are critical to help sustain combustion when excessive fuel deposition causes premature quenching. Copper, chromium, and titanium nanoparticles, on average, decrease the amount of fuel deposited and consumed during the process by 7%, increase the apparent H/C ratio of the coke by 15%, and increase the molar CO 2 /CO ratio of the combustion gas by 31%. These changes manifest in a decrease in water production (ΔWOR avg = −19%) and an average increase in oil production of 20%.

Formulation of surfactant EOR systems usually involves multiple salinity scans of the phase behavior of crude oil, surfactant, and brine systems. Usually, the measurements are made in sealed pipettes for accurate volume measurements without fluid loss. The volumes of oil and water solubilized into the microemulsion phase are observed to determine the optimal salinity and estimate the interfacial tension. Viscous emulsions and surfactant-rich condensed phases are not desirable. However, the only estimate of viscosity from the salinity scans is the movement (or lack of movement) of the interfaces upon tilting of the tube. A falling-sphere viscometer with multiple, ring-shaped, inductive proximity sensors is described. The device uses 0.78 mm, gold-coated, paramagnetic, 440 stainless steel spheres. With this size sphere, it is possible to accurately estimate the viscosity of fluids from 1 to 1,200 cp. The spheres are paramagnetic, so they can be lifted to the top of the tube with a magnet, and meet the constraints of a Reynolds number less than 800 for low viscosity fluids, and a velocity fast enough to be detected for a high viscosity fluid. A data acquisition system control a set of four sensors for signal conditioning and time recording. When the same phase spans the space between a pair of sensors, its viscosity can be estimated directly from the transit time of the sphere. When two or three phases span the space between a pair of sensors, the viscosity of the undetermined phase can be estimated from the transit time across it after correcting for the transit times across the upper and/or lower phases. Thus the viscosity of a middle-phase microemulsion can be estimated even if it spans only a small fraction of the distance between sensors. The system has been used to measure viscosities of lower-, middle-, and upper-phase microemulsions at ambient temperature. Also, apparent viscosities of macroemulsions and of the "colloidal dispersion" layer at the top of a lower-phase microemulsion have been measured.

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We developed a novel technique based upon time-lapse infrared (IR) images to relate the effects of crude-oil oxidation kinetics on flow during one-dimensional homogeneous and heterogeneous laboratory-scale combustion tube experiments. We performed combustion tube experiments under variable conditions including different sands (i.e., grain-size distribution), air injection rate history (constant versus variable), degree of packing heterogeneity, and reaction heterogeneity. The latter is achieved by using reaction enhancing nanoparticles in controlled packing configurations. During every experiment, we obtain high-resolution IR images of the outer wall of the combustion tube that we calibrate using point-wise temperature measurements from a thermocouple. Here, a new experimental workflow that uses these images and combines knowledge obtained from kinetic cell experiments is used to isolate the spatial zones within the tube where so-called low-temperature and high-temperature oxidation (pseudoreaction regimes) occurs during combustion tube experiments for the first time. Additionally, the IR imaging technique is shown to provide new insight into the propagation of the combustion front in homogeneous and heterogeneous systems and, importantly, visualizes gravity drainage of hot oil.

This paper presents a new workflow for the simulation of in-situ combustion (ISC) dynamics. In the proposed method, data from kinetic cell experiments, depicting the combustion chemistry, are tabulated and graphed based on the isoconversional principle. The tables hold the reaction rates used to predict the production and consumption of chemical species during in-situ combustion. This new method of representing kinetics without the Arrhenius method is applied on one synthetic and two real kinetic cell experiments. In each case, the new method reasonably captures the reaction pathways taken by the reacting species as the combustive process occurs. A data-density sensitivity study on the tabulated rates for the real case shows that only four experiments are required to capture adequately the kinetics of the combustion process. The results are, however, found to be sensitive to the size of the time step taken. The method predicts critical changes in the reaction rates as the experiment is exposed to different temperature conditions, thereby capturing the speed of the combustion front, temperature profile, and fluid compositions of a simulated combustion tube experiment. The direct use of the data ensures flexibility of the reaction rates with time and temperature. In addition, the non-Arrhenius kinetics technique eliminates the need for a descriptive reaction scheme that is typically computationally demanding, and instead focuses on the overall changes in the carbon oxides, oil, water and heat occurring at any time. Significantly, less tuning of parameters is required to match laboratory experiments because laboratory observations are easier to enforce.