Vladimir Alvarado

University of Wyoming | UW · Department of Chemical Engineering

The tight nature of shale formations calls for hydraulic fracturing techniques able of altering the pore architecture to facilitate the production of hydrocarbon resources. The composition, pH, salinity, density and chemistry of Hydraulic Fracturing Fluids (HFF) vary substantially depending on reservoir characteristics. pH is among the most importa...

In this work, we use the “Design and Analysis of Computer Experiments” (DACE) technique to analyze the sensitivity of CO2 storage in fractured aquifers. The aquifer static or geogical model was inspired by the Tensleep formation at Teapot Dome, a potential CO2 storage target in Wyoming. The CO2 storage performance in aquifers is comprehensively sim...

Carbon dioxide (CO2) injection into a deep saline aquifer can dissolve into formation brine and generate carbonic acid. The resulting acid can drive fluid-rock geochemical reactions. The impact of these fluid-rock geochemical reactions on porosity, permeability, and multiphase flow responses is relevant to the determination of CO2 storage capacity...

In this study, we measured the interfacial tensions (IFTs) of brine/hydrogen-methane (H2–CH4) mixtures. We also measured the static contact angles of H2–CH4 mixtures in contact with brine and oil-wet sandstone and limestone rocks at reservoir conditions. The measurements were conducted using pendant drop and rising/captive bubble techniques. The te...

Phase equilibria analysis in two-phase systems requires discernment of the individual phases as well as the interfacial region. The phase behavior of fluids in constraint geometries have been studied through several techniques. High-Field Nuclear Magnetic Resonance (HF-NMR) can be used to detect fluid phases, i.e. gas, liquid, or supercritical flui...

Numerical reservoir simulation of CO2 storage in geological formations is computationally expensive due to the complex, and often coupled, multiphase flow phenomena, and the large spatial and temporal scales. Upscaling is a family of techniques used to decrease petrophysical degrees of freedom from a fine-scale model to a coarser one such that the...

In this paper, we investigated the interplay of rock deformation, micro-crack development, and fluid flow response using a stress-dependent pore network model. This model incorporates a representation of grains and cements interactions to enable predictions of the mechanical response from micro-scale elements. To complete the model, fluid flow resp...

Integration of petrophysical and geological information is critical to simulation of subsurface carbon storage (GCS). In this sense, two depositional facies were identified from the core description and well-log interpretation, namely massive (MS) and cross-bedded (CB) facies groups. Additionally, pore-scale characteristics were studied by a combin...

Wetting conditions and fluid–fluid interfacial properties are essential to understanding oil recovery in the context of low-salinity and smart waterflooding. Many have deemed wettability alteration to be the dominant interaction, while some highlight the importance of fluid–fluid interactions. In some rock-fluid systems, benefits from the use of ad...

Tardigrades, also known as water bears, make up a phylum of small but extremely hardy animals, renowned for their ability to survive extreme stresses, including desiccation. How tardigrades survive desiccation is one of the enduring mysteries of animal physiology. Here we show that CAHS D, an intrinsically disordered protein belonging to a unique f...

The hydraulic fracturing stimulation process can alter petrophysical and flow properties of the shale matrix in unconventional reservoirs. These alterations can result from interactions with native and exogenous fluids, and can be detrimental to reservoir productivity. Different experimental procedures have been proposed to study reactive processes...

The analysis of porosity and pore structure of shale rocks has received special attention in the last decades as unconventional reservoir hydrocarbons have become a larger parcel of the oil and gas market. A variety of techniques are available to provide a satisfactory description of these porous media. Some techniques are based on saturating the p...

This study aims at understanding effects of sub-core scale petrophysical heterogeneity on CO2-brine multiphase flow properties during CO2 injection in samples of the Minnelusa Formation in Wyoming, representing differing lithofacies. Unsteady-state CO2-brine drainage tests were performed on a core sample from a dune deposit with laminated bedding a...

A large percentage of petroleum reserves are located in carbonate reservoirs, which can be divided into limestone, chalk and dolomite. Roughly the oil recovery from carbonates is below the 30% due to the strong oil wetness, low permeability, abundance of natural fractures, and inhomogeneous rock properties Austad (2013). Injection of adjusted brine...

Pore architecture regulates fluid flow between unconventional shale reservoir and hydraulically-induced fractures. Imbibition of stimulation fluid may change this architecture and alter hydrocarbon flow. Hydrothermal experiments were conducted at reservoir conditions (125 °C, 45 MPa) to test two hypotheses: 1) Shale, not stimulation fluid, dominate...

Ice adhesion on aerospace-relevant materials is both complex and not well understood. Measuring such adhesion and understanding the underlying physics involved require reliable testing techniques that can yield multifaceted data sets. The latter includes the surface morphology, that is, roughness, and its spatial correlation structure, resolving su...

Geologic carbon sequestration (GCS) is considered a feasible technology for storing substantive volumes of greenhouse gases in subsurface geological formations. In the reservoir, far from carbon dioxide (CO2) injection wells or in post-injection scenarios, diffusion dominates over advection. This condition conjoins with spatially distributed geoche...

This research studied seismic source mechanisms of acoustic emission (AE) events generated during the failure of intact and jointed rock samples using a microscale mechanical-seismicity coupled microscale model. During rock failure, forces and displacements around microcracks were measured in the model to determine seismic moment tensor. Interpreta...

Plain Language Summary Emitting a large amount of greenhouse gases into the atmosphere has disrupted the global carbon cycle. CO2 captured from various sources could be transported to a close‐by site for injection into deep saline aquifers or oil/gas reservoirs for storage or/and enhanced oil recovery. Reactions between the rock and the carbonic ac...

Reliably determining the physical properties of ice (e.g., crystal structure, adhesion strength, interfacial state, and molecular orientation) has proven to be both challenging and highly dependent on experiment-specific conditions, including surface roughness, ice formation, water purity, and measurement method. Here, non-destructive measurements...

Micro‐tomography (μCT) and nuclear magnetic resonance (NMR) have been used to characterize porous media for decades. Magnetic Resonance Imaging (MRI) enables direct visualization of pore architecture and many pulse sequences exist. In this work, we tested the MRI pulse sequence Zero Echo Time (ZTE) to study sandstone and carbonate for its ability t...

Nonlinearity of Mohr envelopes confirmed by past laboratory test data can be of considerable importance in theoretical interpretation of rock strength behaviors and many practical applications. Current nonlinear failure criteria are introduced with parameters to empirically fit test data, and the physical and mechanical meanings of these fitting pa...

Wettability has been shown to influence oil recovery. This property has become central to low-salinity (LSW) and smart (SWF) water flooding recovery mechanisms research. The challenge lies in the fact that oil recovery results from the combined effects of solid-liquid and liquid-liquid interactions. This demands methods that allow an independent in...

The objective of the present work is to determine the effect of silica nanoparticles on the microrheological properties of heavy and extra-heavy crude oils using time-domain nuclear magnetic resonance (TD-NMR) methods. Three heavy crude oils with different asphaltene contents were studied. The oils steady-state rheograms were collected as a functio...

The presence of compliant pores in rocks is important for understanding the stress–strain behaviors under different stress conditions. This paper describes findings on the effect of compliant pores on the mechanical behavior of a reservoir sandstone under hydrostatic and triaxial compression. Laboratory experiments were conducted at reservoir tempe...

Injection of a generic naphthenic acid blend in waterflooding experiments has been shown to enhance oil recovery. A brine-oil interfacial response upon addition of organic acids has also been recorded and linked to the improved recovery response. The purpose of this work is to analyze the effect of several individual naphthenic acids on the oil-wat...

Laboratory measurements including gas (N2) porosity and permeability, time-domain nuclear magnetic resonance, thin section, and scanning electron microscopy analysis were conducted to obtain petrographical and petrophysical descriptions of the Weber Sandstone and Madison Limestone at the Rock Spring Uplift, a potential carbon dioxide storage site i...

Drawing on techniques from both petroleum engineering and economics, we analyze how oil fields that use CO2 injection to enhance oil recovery are likely to respond to CO2 storage incentives by “co-optimizing” oil recovery and CO2 sequestration. We focus specifically on predicting the CO2-injection path that co-optimizing operators will choose, and...

In this work, nuclear magnetic resonance (NMR) spectroscopy is used to investigate surfactant phase behavior over a broad concentration region. This technique is an adaptation of a previously developed method applied to detect the critical micelle concentration (CMC) of surfactants. In this method, a surfactant concentration is correlated to the no...

Injection of water with a designed chemistry has been proposed as a novel enhanced-oil-recovery (EOR) method, commonly referred to as low-salinity (LS) or smart waterflooding, among other labels. The multiple names encompass a family of EOR methods that rely on modifying injection-water chemistry to increase oil recovery. Despite successful laborat...

The present work proposes for the first time a mathematical model for describing the rheological behavior of heavy and extra-heavy crude oils in the presence of nanoparticles. This model results from the combination of two existing mathematical models. The first one applies to the rheology of pseudoplastic substances, i.e., the Herschel-Bulkley mod...

In this study, low-salinity waterflooding enhanced-oil recovery mechanisms linked to the water–crude oil interfacial viscoelastic response are investigated considering a distinct interfacial effect, namely the water-crude oil interfacial viscoelasticity response. In contrast, wettability alteration is interpreted through analysis of capillary hyste...

Lowering the injection water salinity or modifying its chemistry can improve waterflooding displacement efficiency. This water modification has been frequently alluded to increase rock water-wetness. However, the presence of sulfate anions in the aqueous phase is shown here to also alter the crude oil–water interfacial rheology drastically, in ways...

H pulsed-field gradient nuclear magnetic resonance was used to study early-time water diffusivity in porous media. The method has also been proven useful to characterize porous media from the standpoint of time-dependent diffusion. In porous media such as zeolite, biological cells or reservoir rocks, water molecular diffusion is time-as well as ion...

Low salinity waterflooding (LSWF) has been proposed as way to increase oil recovery. Albeit various proposed mechanisms for LSWF improved oil recovery, no consensus exists currently. Alvarado et al. showed that a strong correlation between incremental oil recovery and high interfacial viscoelasticity exists. This interfacial response to LSWF has be...

Smart waterflooding in hydrocarbon reservoirs has been a subject of intense speculation. Several recovery mechanisms have been proposed, including wettability alteration toward water-wetness. In contrast, the role of fluid-fluid interactions has been overlooked. In this study, we evaluate rock-fluid interactions in connection with the observed incr...

The primary objective of this study is to investigate the effects of SiO2 nanoparticles on improving the rheological behavior and inhibition of the thermal degradation of hydrolyzed polyacrylamide (HPAM) solutions. The SiO2-HPAM interactions were evaluated through i) Polymer adsorption onto nanoparticles, ii) rheological studies, and iii) evaluatio...

The main objective of this study is twofold. First, we evaluate the effect of nanofluids as additives to optimize the transport of heavy crude oil using steady-state rheological measurements and dynamic flow tests. The use of these additives produces viscosity reduction for heavy (HO) and extra heavy (EHO) crude oils. Second, we show how the additi...

At the request of the Publisher, the following article has been retracted for redundant publication. Taborda EA, Franco CA, Ruiz AM, Alvarado V, Cortés FB (2017) Striking behavior of the rheology in heavy crude oils by adding nanoparticles. Adsorption Science & Technology. Epub ahead of print 29 August 2017. DOI: 10.1177/0263617417727996 . After pu...

Experimental observations clearly show that dispersed-phase pore-scale flow effects of emulsion flow are responsible for drop entrapment at pore throats and this strongly depends on local capillary number. As a result, this dimensionless number is key to parametrize emulsion flooding for EOR purposes. In this work, we incorporate capillary number e...

We present a reservoir geophysics study, including rock physics modeling and seismic inversion, of a carbon dioxide sequestration site in Southwestern Wyoming, namely the Rock Springs Uplift, and build a petrophysical model for the potential injection reservoirs for carbon dioxide sequestration. Our objectives include the facies classification and...

Heavy and extra-heavy oils generally exhibit high viscosity, which is detrimental to their production, transport, and refining. The Oil & Gas industry has thoroughly investigated the use of chemical agents to improve the mobility of these types of low-quality crude oils at the surface as well as under reservoir conditions for many years. In this se...

Smart-water flooding has become increasingly more important as Enhanced-Oil Recovery technology in recent years. However, the observed incremental recovery varies significantly from case to case, even when the reservoir rock lithology, and water and oil characteristics are similar. In our earlier research, we proposed that a favorable crude-oil bri...

Chemical enhanced-oil recovery has been applied successfully in reservoirs with mild salinity and temperature conditions. Offshore reservoirs challenge chemical flooding, e.g. low-tension and foam flooding, because of the combined hardness and salinity of seawater along with characteristics of the reservoir connate brine. These physico-chemical con...

In this work, we evaluate the effect of nanoparticles and nanofluids as viscosity reducers for heavy crude oil (HO). The effect of alumina, silica and acidic silica nanoparticles was evaluated through n-C7 asphaltene adsorption and aggregation tests using UV–vis spectrophotometry and dynamic light scattering. The nanoparticles of acidic silica were...

In this paper, we examine the impact of aqueous phase ionic strength and ionic composition on viscoelastic properties of the water-crude oil interfacial film by conducting interfacial shear rheological measurements under controlled water chemistry and aging time. A double-wall ring geometry is utilized in oscillatory mode to measure the film visco-...

In this work, we analyze measurements of drainage, spontaneous imbibition and forced imbibition capillary pressure curves in conjunction with two-electrode resistivity on sandstone core samples under low- and high-salinity waterflooding conditions. State-of-the-art laboratory equipment able to work with actual reservoir fluids at reservoir conditio...

Laboratory experiments evaluated two shale caprock formations, the Gothic Shale and Marine Tuscaloosa Formation, at conditions relevant to carbon dioxide (CO 2) sequestration. Both rocks were exposed to CO 2-saturated brines at 160°C and 15 MPa for *45 days. Baseline experiments for both rocks were pressurized with argon to 15 MPa for *35 days. Var...

Carbon capture, utilization, and storage, one proposed method of reducing anthropogenic emissions of CO 2 , relies on low permeability formations, such as shales, above injection formations to prevent upward migration of the injected CO 2. Porosity in caprocks evaluated for sealing capacity before injection can be altered by geochemical reactions i...

Multiphase fluid flow dynamics dominate processes used to recover the majority of hydrocarbon resources produced by global energy industries. Micromodels have long been used to recapitulate geometric features of these processes, allowing for the phenomenological validation of multiphase porous media transport models. Notably, these platform surroga...

Chemical enhanced-oil recovery has been applied successfully in reservoirs with mild salinity and temperature conditions. Offshore reservoirs challenge chemical flooding, e.g. low-tension and foam flooding, because of the combined hardness and salinity of seawater along with characteristics of the reservoir connate brine. These physico-chemical con...

Low-salinity waterflooding has been portrayed as an effective enhanced-oil recovery technology. Despite compelling laboratory and field evidence of its potential, the underlying mechanisms still remain controversial. In this study, the enhanced-oil recovery mechanisms are investigated considering a distinct interfacial effect, i.e. water-crude oil...

Recovery from oil reservoirs could be improved by lowering the injection water salinity or by modifying the water injection chemistry. This has been proposed as a way to increase rock water-wetness. However, we have observed that the presence of sulfate anions in the aqueous phase can change the crude oil-water interfacial rheology drastically, and...

Snap-off of bubbles and drops in constricted capillaries occurs in many different situations, from bio-fluid to multiphase flow in porous media. The breakup process has been extensively analyzed both by theory and experiments, but most work has been limited to pure interfaces, at which the surface stress is isotropic and fully defined by the interf...

In this work, NMR spectroscopy is used to investigate surfactant phase behavior relevant to chemical enhanced oil recovery. The effect of solution electrical conductivity on the NMR signals was corrected using reference spectra of known conductivity. This allowed us to develop a semi-quantitative method to estimate surfactant concentration by corre...

The work addresses technical issues of waterflooding operations in offshore environments from the standpoint of fluid-fluid and rock-fluid interactions. Seawater is the preferred source of injection fluid for waterflooding in offshore reservoirs. Given the elevated CAPital EXpenditure (CAPEX), seawater treatment is generally driven by the need to m...

Injection of crude oil-in-water emulsion in tertiary mode has been recognized as a potential method to increase oil recovery. Better understanding of emulsion flow through porous media is needed to develop practical improved oil recovery processes based on emulsion flooding mechanisms. In this study, two sets of experiments were carried out to furt...

Drawing on techniques from both petroleum engineering and economics, we analyze how oil fields that use CO2 injection to enhance oil recovery (CO2-E0R projects) are likely to respond to incentives that promote CO2 sequestration. Most engineering studies that have examined how oil-field operators should "co-optimize" oil recovery and CO2 sequestrati...

Low salinity waterflooding is a promising Improved Oil Recovery (IOR) process showing growing activity since discovery. However, incremental recovery over traditional waterflooding varies significantly. Numerous investigations have attempted to prove or disprove recovery mechanisms associated to this process. In our earlier research, we proposed th...

Alkali-surfactant-polymer (ASP) flooding is a commercially viable enhanced oil recovery method. The complexity of chemical interactions, multi-phase flow, emulsification, capillary number changes and upscaling issues, especially in highly heterogeneous reservoir, make field designs difficult to extrapolate from coreflood measurements. In this work,...

Studying rock joint deformation including both slippage and opening mechanisms provides an opportunity to investigate the connection between the permeability and seismic source mechanisms. A micro-scale fluid flow-geomechanics-seismicity model was built to evaluate the transport response and failure mechanism of microcracks developed along a joint...

To study the effect of fracture properties on mechanical and fluid flow behavior of fractured rocks, we developed a micro-scale hydro-mechanical model. Modeling grains and studying their interactions are used to predict the mechanical response of digital rock samples. Fluid flow behavior is obtained through a realistic network model of the pore spa...

For industrial-scale CO2 injection in saline formations, produced CO2 and pressure buildup can limit storage capacity and efficiency. Sensitivity analysis on operational strategies and reservoir parameters serves to select the optimum injection strategy to increase injectivity, relieve pressure buildup, improve CO2 trapping efficiency, and constrai...

Injection of water with designed chemistry has been proposed as a novel enhanced-oil recovery (EOR) method, commonly referred to as low-salinity or smart waterflooding, among other names. The plethora of names encompasses a family of EOR methods that rely on modifying injection water chemistry to increase oil recovery. Despite successful laboratory...

[1] To explain how fracture roughness affects seismic source and transport response of deformed fractured rock, we developed a micro-scale fluid flow-geomechanics-seismicity model. The modeling method considers comprehensive grains and cement interactions. Fluid flow behavior is obtained through realistic network models of the pore space in the com...

Various mechanisms controlling the multiphase flow in a real geological porous medium such as those associated with carbon dioxide (CO2) storage in a saline reservoir can lead to a patchy saturation distribution. Successful monitoring of CO2 plumes using time-lapse seismic data under these conditions is a challenge due to the degree of uncertainty...

This paper presents an analysis on the potential of Enhanced-Oil Recovery (EOR) and its challenges in offshore environments. EOR experience gained in onshore and shallow offshore should be translatable to offshore, but common sense developed over years of exhaustive laboratory research, modeling based on our best understanding of recovery mechanism...