Mahmood Amani - Academia.edu (original) (raw)

Papers by Mahmood Amani

Research paper thumbnail of Experimental and Numerical Investigations of Cement Bonding Properties

Materials

Well integrity is of high importance during the entire well life span especially when renewable e... more Well integrity is of high importance during the entire well life span especially when renewable energy resources such as geothermal are designed to cover the increasing world energy demand. Many studies have documented the importance of the casing–cement interfacial bonding to ensure critical well integrity achievements; however, laboratory experiments and field data are not always aligned. Furthermore, Finite Element Analysis shows relatively high discrepancies compared with the results of various scholarly published works. The limitations in the FEA are most probably generated by the casing–cement interaction modeling parameters. Typically, the contact between casing and cement is modeled using the so-called CZM method, which includes the shear debonding process into the FEA. Several setups have been used in the past to determine the interfacial casing–cement bonding shear strength. Some of these setups are briefly summarized herein. The novelty of this paper consists in the combi...

Research paper thumbnail of A Comprehensive Overview of the Use of Compressible Drilling Fluids, Advantages and Challenges

The idea of using air or gas as a circulating medium in drilling was introduced in early 1950’s. ... more The idea of using air or gas as a circulating medium in drilling was introduced in early 1950’s. Despite the fact that this application was initially basic, petroleum engineers had an opportunity to increase bit life and penetration rates. Since then, developments have been experienced in the techniques used in air and gas drilling. This explains why the drilling method is widely used as a method of reducing the drilling cost and time required to achieve a certain output. An increase in the cost per foot of hole created a need for the operators to come up with drilling techniques associated with better penetration rates. Through continuous improvements in air drilling practices and equipment, engineers continue to achieve notable increases in ROP over the rates obtained when a liquid medium is used. Air drilling has moved from the use of small compressors at low pressures to the use of larger compressors, volumes and pressures. Practical experience in this field made engineers to ta...

Research paper thumbnail of Barite segregations is a phenomenon that can lead to dire problems when not controlled properly

Research paper thumbnail of Experimental investigation of deterioration in mechanical properties of oil-based mud (OBM) contaminated API cement slurries correlations for ultrasonic cement analysis

Journal of Petroleum Science and Engineering

Abstract Well construction, well abandonment and restoration of well integrity are the reasons at... more Abstract Well construction, well abandonment and restoration of well integrity are the reasons at a broad level why cementing jobs are performed. During well construction phase, the primary objective of cementing job is to replace the drilling mud in the annulus with pure cement. Intermixing of the drilling mud and the cement slurry produces unpumpable mixture, especially in the case of OBM. As literature review suggests the displacement efficiency of spacers and pre-flushes used to displace the drilling mud is not 100%, cement slurries are contaminated with drilling mud left behind the casing. Recently, several research groups have performed studies to understand the strength development phenomenon of OBM contaminated cement slurries, but they failed to document properly the experimental procedures used and correlations for the strength development of OBM contaminated cement slurries. The primary aim of this study was to develop a standard laboratory experimental procedure for understanding the strength development of OBM contaminated cement slurries and develop correlations for future references. This extensive study was carried out on API Class C cement samples cured at room temperature and elevated temperature. Destructive as well as non-destructive tests were performed on the contaminated as well as uncontaminated cement samples to measure the uniaxial compressive strength (UCS) and the ultrasonic pulse velocity (UPV) respectively. Results obtained from these tests showed deterioration in the strength of cement samples as the OBM contamination increases. Correlations for early strength development of OBM contaminated cement slurries were developed using the test results. These correlations developed would help the operators in better estimation of the strength developed by the OBM contaminated cement slurries. In other words, better estimation of weight on cement (WOC) time using the more accurate strength development correlations.

Research paper thumbnail of Alternative and Potential Uses for the Sulfur Byproducts Produced from Oil and Gas Fields

International Journal of Organic Chemistry

Along with oil and gas operations, huge amounts of sulfur byproducts are produced. For example, i... more Along with oil and gas operations, huge amounts of sulfur byproducts are produced. For example, in the State of Qatar which has the third largest proven reserves of natural gas, an incredible amount of sulfur is produced as byproduct from its natural gas processing facilities. The amount of produced sulfur surpasses by far the amount that can be utilized currently in the country. Hydrogen sulfide (H2S) existing in natural gas extracted from Qatar’s North Field is converted to elemental sulfur using the conventional Claus process. Managing byproduct sulfur from natural gas processing is a key aspect of economic development and environmental protection in many countries with oil and gas facilities. Therefore, new markets must be found to utilize sulfur to avoid disposal crises. Sulfur byproduct from natural gas can be utilized for various applications. This paper discusses alternative potential uses for sulfur in addition to the current practices of sulfur utilization. Some of these alternative applications of sulfur byproducts include the potential usage for medicinal uses, road construction, batteries, hydrogen production, structural additives, solar energy, waste treatment, arsenite removal, and production of maize.

Research paper thumbnail of Direct Mass Spectroscopy Analysis and Comparison of Middle Eastern and Texas Crude Oils

International Journal of Organic Chemistry

Research paper thumbnail of Direct Mass Spectroscopy Analysis and Comparison of Middle Eastern and Texas Crude Oils

International Journal of Organic Chemistry, 2017

Research paper thumbnail of Influence of CNT-Nanoparticles in the Filtrate Characteristics and Filter Cake Formation of a Water-Based Drilling Fluid

Proceeding of 5th Thermal and Fluids Engineering Conference (TFEC)

Research paper thumbnail of Foam Stability - Does Well Inclination Matter?

SPE/ICoTA Well Intervention Conference and Exhibition

To minimize fluid loss and the associated formation damage, underbalanced coiled tubing (CT) is o... more To minimize fluid loss and the associated formation damage, underbalanced coiled tubing (CT) is one of the preferred methods to perform cleanout operations and re-establish communication with an open completion interval. Because of their high viscosity and structure, stable foams are suitable cleanout fluid when underbalanced CT operations are applied. However, unstable foams do not possess high viscosity and as a result, they are poor in cleanout operations, especially in inclined wellbores. This study is aimed to investigate the effects of wellbore inclination on the stability of foams. In this study, foam drainage experiments were carried out using a flow loop that has foam drainage measurement section and pipe viscometers. To verify proper foam generation and validate the accuracy of measurements, foam rheology was measured using pipe viscometers. Drainage experiments were performed with aqueous, polymer-based, and oil-based foams in concentric annulus and pipe under pressurized...

Research paper thumbnail of Water Chemistry in Oil and Gas Operations: Scales Properties and Composition

International Journal of Organic Chemistry

Research paper thumbnail of Rheological studies of a water based drilling mud suspended with carbon nano particles

Qatar Foundation Annual Research Conference Proceedings Volume 2018 Issue 1

Research paper thumbnail of Introduction to Smart Oil and Gas Wells: Drilling, Completion and Monitoring Solutions

International Journal of Petrochemistry and Research

Research paper thumbnail of Rheology and hydraulics of polymer-based foams at elevated temperatures

Journal of Petroleum Science and Engineering

Abstract Foam has been successfully used for different operations like well stimulation, drilling... more Abstract Foam has been successfully used for different operations like well stimulation, drilling, enhanced oil recovery (EOR), cleanout, and acidizing operations in the oil and gas industry. Additionally, the low liquid content of foam provides a distinct advantage in terms of lesser material requirements. However, accurate prediction of rheology is necessary for the success of field operations, which requires a rheological model that incorporates the effect of temperature on foam properties as it circulates downhole. In the present investigation, polyanionic cellulose (PAC) based foam was generated using nitrogen as the gas phase and its rheology was determined using a recirculating flow loop that has three pipe viscometers (3.05, 6.22, and 12.7 mm ID) and a fully-eccentric annular section (9.53 mm OD × 12.57 mm ID). Experiments were conducted within the temperature range of 24 to 149 °C and at various foam qualities (gas phase volume fraction). The foam was circulated at different flow rates and the differential pressure across each pipe section was recorded. All tests were conducted at 6.89 MPa. The foams displayed power-law fluid behavior in the shear rate range tested (100–5000 s−1), which is often experienced in the wellbore. Like its base liquid, polymer foam exhibited thermal thinning and a significant rheology change with temperature. Only high-quality foam (75%) at ambient temperature (24 °C) showed yielding behavior, which was measured in a pipe viscometer under static condition. The disappearance of yield stress at elevated temperature could be attributed to thermal thinning of the liquid phase that weakens the strength of bubble structure. Experimental data is used to develop new correlations to predict power-law fluid parameters as a function of temperature, base fluid properties, and foam quality. Moreover, the measurements are compared with the predictions of existing models, and discrepancies are observed, which could be attributed to the variation in foam generation technique, the nature and concentration of polymer, and the concentration of surfactant used in the experiments in which data was obtained to develop the models. Furthermore, annular pressure loss measurements obtained at low temperatures (24 and 79 °C) show predominantly good agreement with predictions of a hydraulic model that uses the new correlations. Discrepancies increased with temperature as the foam becomes unstable due to thermal thinning of the liquid film and subsequent weakening of bubble structure.

Research paper thumbnail of Sensitive acetone detection with a mid-IR interband cascade laser and wavelength modulation spectroscopy

OSA Continuum

An efficient method for the detection of acetone, an important biomarker in exhaled breath, by ut... more An efficient method for the detection of acetone, an important biomarker in exhaled breath, by utilizing wavelength modulation spectroscopy (WMS) with a mid-infrared distributed feedback interband cascade laser (DFB-ICL) is presented. The performance of the DFB-ICL laser is characterized, and its linewidth is measured to be mbox(3.mbox39pm0.mbox15)\mbox{(3}.\mbox{39} \pm 0.\mbox{15)}mbox(3.mbox39pm0.mbox15)(3.39±0.15) MHz by beating the output with an auxiliary mid-IR frequency comb over 50 ms. The measured asymmetric acetone absorption profile with the center wavelength around 3367 nm is fitted by the pseudo-Voigt function. The phase shift between the intensity and frequency modulations is determined and used for processing the results. The sensor is tested by performing measurements with calibration mixtures of acetone in nitrogen, and the detection limits of 0.58 ppm and 0.12 ppm were determined with 1 s and 60 s signal averaging times, respectively. Our work shows that wavelength modulation spectroscopy with a DFB-ICL laser complimented by a multipass cell for higher sensitivity can be efficiently used for acetone detection and is promising for sensitive breath analysis.

Research paper thumbnail of Sensitive Spectroscopic Analysis of Biomarkers in Exhaled Breath

International Journal of Thermophysics

AbstractWe have developed a novel optical setup which is based on a high finesse cavity and absor... more AbstractWe have developed a novel optical setup which is based on a high finesse cavity and absorption laser spectroscopy in the near-IR spectral region. In pilot experiments, spectrally resolved absorption measurements of biomarkers in exhaled breath, such as methane and acetone, were carried out using cavity ring-down spectroscopy (CRDS). With a 172-cm-long cavity, an efficient optical path of ~ 132 km was achieved. The CRDS technique is well suited for such measurements due to its high sensitivity and good spectral resolution. The detection limits for methane of ~ 8 ppbv and acetone of ~ 2.1 ppbv with spectral sampling of 0.005 cm−1 were achieved, which allowed to analyze multicomponent gas mixtures and to observe absorption peaks of 12CH4 and 13CH4. Further improvements of the technique have the potential to realize diagnostics of health conditions based on a multicomponent analysis of breath samples.

Research paper thumbnail of Rheology of a colloidal suspension of carbon nanotube particles in a water-based drilling fluid

Powder Technology

Abstract High-pressure and high-temperature rheology of a nanomud suspension is studied. The nano... more Abstract High-pressure and high-temperature rheology of a nanomud suspension is studied. The nanomud is prepared by dispersing a water-based drilling mud suspension with multi-walled carbon nanotubes (MWCNT). Effect of nanoparticle concentration, shear rate, pressure, and temperature are investigated. The pressure and temperature are independently varied from ambient conditions to 170 MPa and 180 °C respectively. The results presented show that the addition of CNT increases the viscosity of the drilling mud. A shear thinning non-Newtonian behavior is observed for the basemud and the nanomud samples at all pressures and temperatures. The basemud showed an increase in viscosity with an increase in pressure. However, with CNT particle addition this trend is observed to have reversed. For the basemud and the nanomud at lower concentrations, the viscosity values are observed to have initially increased with the increase in temperature and to have reduced beyond 100 °C. For a higher particle loading, a consistent decrease in viscosity with temperature is observed. The behavior of higher concentration nanomud samples with respect to pressure and temperature are seen to follow a similar trend to that of water. It is reasoned that an adequate addition of CNT nanoparticles helps retain the mud particles in a more homogenous and stable state, where they are held within the CNT chains. However, with further addition of CNT nanoparticles, the mud particles become agglomerated with the long chains of CNT, eventually separating water from the drilling fluid mixture.

Research paper thumbnail of Intelligent Tool To Design Drilling, Spacer, Cement Slurry, and Fracturing Fluids by Use of Machine-Learning Algorithms

SPE Drilling & Completion

Summary Design of drilling fluids, spacers, cement slurries, and fracturing fluids is often done ... more Summary Design of drilling fluids, spacers, cement slurries, and fracturing fluids is often done by trial and error in the laboratory. In the first step, the required properties of these fluids are categorized and then efforts will be started with a rough idea of the optimal composition. This first guess usually depends on the experience of the laboratory analyst or fluid engineer. Afterward, the trial-and-error testing starts, and it continues until the fluid design moves closer to the desired fluid criteria. There are several test data that would not be used in this method, and it is difficult to digest a large amount of information by the user. Trial and error could be time-consuming, very costly, and misleading. Today, there is a need for an intelligent system that uses all the available data (big data), even if the data sets are not close to the desired goal, and offers insights for fluid designs. This paper conducted a study on the application of machine-learning-based methodo...

Research paper thumbnail of Extension of filament propagation in water with Bessel-Gaussian beams

Research paper thumbnail of Advanced Fluid Data-Driven Analytics: One Step Closer to Well Integrity Excellence

International Petroleum Technology Conference, 2015

Research paper thumbnail of Effect of Low Elastic Wave Radiation on Fluid Percolation Through Fractured Media

73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011

During past few years, models for predicting the flow behavior under radiation of elastic waves h... more During past few years, models for predicting the flow behavior under radiation of elastic waves have been presented for non-fractured porous. However, little attention has been paid to mathematical modeling of this phenomenon in fractured media. In this work, the model presented by Pavel et.al is extended to fractured systems. Firstly, flow behavior of Bingham plastic crude oil is investigated in the fracture and secondly, acoustic waves role on capillary trapping is demonstrated. The results of mathematical model clarified that radiation of wave with low frequency and low intensity increases the flow rate and decreases the minimum pressure gradient required for flow of Bingham plastic fluids in fractured media. Besides, it is inferred that lower the saturation of oil in a two phase system in fracture, lower will the wave radiation be effectual. Further, it is shown that the effect of elastic wave is of less significance in higher pressure gradients. So it is revealed that low frequency wave technology would not be applicable in high pressure fractured reservoirs. The results of modeling presented in this work can be a path breaking to future studies in the field of fractured reservoirs acoustic stimulation.

Research paper thumbnail of Experimental and Numerical Investigations of Cement Bonding Properties

Materials

Well integrity is of high importance during the entire well life span especially when renewable e... more Well integrity is of high importance during the entire well life span especially when renewable energy resources such as geothermal are designed to cover the increasing world energy demand. Many studies have documented the importance of the casing–cement interfacial bonding to ensure critical well integrity achievements; however, laboratory experiments and field data are not always aligned. Furthermore, Finite Element Analysis shows relatively high discrepancies compared with the results of various scholarly published works. The limitations in the FEA are most probably generated by the casing–cement interaction modeling parameters. Typically, the contact between casing and cement is modeled using the so-called CZM method, which includes the shear debonding process into the FEA. Several setups have been used in the past to determine the interfacial casing–cement bonding shear strength. Some of these setups are briefly summarized herein. The novelty of this paper consists in the combi...

Research paper thumbnail of A Comprehensive Overview of the Use of Compressible Drilling Fluids, Advantages and Challenges

The idea of using air or gas as a circulating medium in drilling was introduced in early 1950’s. ... more The idea of using air or gas as a circulating medium in drilling was introduced in early 1950’s. Despite the fact that this application was initially basic, petroleum engineers had an opportunity to increase bit life and penetration rates. Since then, developments have been experienced in the techniques used in air and gas drilling. This explains why the drilling method is widely used as a method of reducing the drilling cost and time required to achieve a certain output. An increase in the cost per foot of hole created a need for the operators to come up with drilling techniques associated with better penetration rates. Through continuous improvements in air drilling practices and equipment, engineers continue to achieve notable increases in ROP over the rates obtained when a liquid medium is used. Air drilling has moved from the use of small compressors at low pressures to the use of larger compressors, volumes and pressures. Practical experience in this field made engineers to ta...

Research paper thumbnail of Barite segregations is a phenomenon that can lead to dire problems when not controlled properly

Research paper thumbnail of Experimental investigation of deterioration in mechanical properties of oil-based mud (OBM) contaminated API cement slurries correlations for ultrasonic cement analysis

Journal of Petroleum Science and Engineering

Abstract Well construction, well abandonment and restoration of well integrity are the reasons at... more Abstract Well construction, well abandonment and restoration of well integrity are the reasons at a broad level why cementing jobs are performed. During well construction phase, the primary objective of cementing job is to replace the drilling mud in the annulus with pure cement. Intermixing of the drilling mud and the cement slurry produces unpumpable mixture, especially in the case of OBM. As literature review suggests the displacement efficiency of spacers and pre-flushes used to displace the drilling mud is not 100%, cement slurries are contaminated with drilling mud left behind the casing. Recently, several research groups have performed studies to understand the strength development phenomenon of OBM contaminated cement slurries, but they failed to document properly the experimental procedures used and correlations for the strength development of OBM contaminated cement slurries. The primary aim of this study was to develop a standard laboratory experimental procedure for understanding the strength development of OBM contaminated cement slurries and develop correlations for future references. This extensive study was carried out on API Class C cement samples cured at room temperature and elevated temperature. Destructive as well as non-destructive tests were performed on the contaminated as well as uncontaminated cement samples to measure the uniaxial compressive strength (UCS) and the ultrasonic pulse velocity (UPV) respectively. Results obtained from these tests showed deterioration in the strength of cement samples as the OBM contamination increases. Correlations for early strength development of OBM contaminated cement slurries were developed using the test results. These correlations developed would help the operators in better estimation of the strength developed by the OBM contaminated cement slurries. In other words, better estimation of weight on cement (WOC) time using the more accurate strength development correlations.

Research paper thumbnail of Alternative and Potential Uses for the Sulfur Byproducts Produced from Oil and Gas Fields

International Journal of Organic Chemistry

Along with oil and gas operations, huge amounts of sulfur byproducts are produced. For example, i... more Along with oil and gas operations, huge amounts of sulfur byproducts are produced. For example, in the State of Qatar which has the third largest proven reserves of natural gas, an incredible amount of sulfur is produced as byproduct from its natural gas processing facilities. The amount of produced sulfur surpasses by far the amount that can be utilized currently in the country. Hydrogen sulfide (H2S) existing in natural gas extracted from Qatar’s North Field is converted to elemental sulfur using the conventional Claus process. Managing byproduct sulfur from natural gas processing is a key aspect of economic development and environmental protection in many countries with oil and gas facilities. Therefore, new markets must be found to utilize sulfur to avoid disposal crises. Sulfur byproduct from natural gas can be utilized for various applications. This paper discusses alternative potential uses for sulfur in addition to the current practices of sulfur utilization. Some of these alternative applications of sulfur byproducts include the potential usage for medicinal uses, road construction, batteries, hydrogen production, structural additives, solar energy, waste treatment, arsenite removal, and production of maize.

Research paper thumbnail of Direct Mass Spectroscopy Analysis and Comparison of Middle Eastern and Texas Crude Oils

International Journal of Organic Chemistry

Research paper thumbnail of Direct Mass Spectroscopy Analysis and Comparison of Middle Eastern and Texas Crude Oils

International Journal of Organic Chemistry, 2017

Research paper thumbnail of Influence of CNT-Nanoparticles in the Filtrate Characteristics and Filter Cake Formation of a Water-Based Drilling Fluid

Proceeding of 5th Thermal and Fluids Engineering Conference (TFEC)

Research paper thumbnail of Foam Stability - Does Well Inclination Matter?

SPE/ICoTA Well Intervention Conference and Exhibition

To minimize fluid loss and the associated formation damage, underbalanced coiled tubing (CT) is o... more To minimize fluid loss and the associated formation damage, underbalanced coiled tubing (CT) is one of the preferred methods to perform cleanout operations and re-establish communication with an open completion interval. Because of their high viscosity and structure, stable foams are suitable cleanout fluid when underbalanced CT operations are applied. However, unstable foams do not possess high viscosity and as a result, they are poor in cleanout operations, especially in inclined wellbores. This study is aimed to investigate the effects of wellbore inclination on the stability of foams. In this study, foam drainage experiments were carried out using a flow loop that has foam drainage measurement section and pipe viscometers. To verify proper foam generation and validate the accuracy of measurements, foam rheology was measured using pipe viscometers. Drainage experiments were performed with aqueous, polymer-based, and oil-based foams in concentric annulus and pipe under pressurized...

Research paper thumbnail of Water Chemistry in Oil and Gas Operations: Scales Properties and Composition

International Journal of Organic Chemistry

Research paper thumbnail of Rheological studies of a water based drilling mud suspended with carbon nano particles

Qatar Foundation Annual Research Conference Proceedings Volume 2018 Issue 1

Research paper thumbnail of Introduction to Smart Oil and Gas Wells: Drilling, Completion and Monitoring Solutions

International Journal of Petrochemistry and Research

Research paper thumbnail of Rheology and hydraulics of polymer-based foams at elevated temperatures

Journal of Petroleum Science and Engineering

Abstract Foam has been successfully used for different operations like well stimulation, drilling... more Abstract Foam has been successfully used for different operations like well stimulation, drilling, enhanced oil recovery (EOR), cleanout, and acidizing operations in the oil and gas industry. Additionally, the low liquid content of foam provides a distinct advantage in terms of lesser material requirements. However, accurate prediction of rheology is necessary for the success of field operations, which requires a rheological model that incorporates the effect of temperature on foam properties as it circulates downhole. In the present investigation, polyanionic cellulose (PAC) based foam was generated using nitrogen as the gas phase and its rheology was determined using a recirculating flow loop that has three pipe viscometers (3.05, 6.22, and 12.7 mm ID) and a fully-eccentric annular section (9.53 mm OD × 12.57 mm ID). Experiments were conducted within the temperature range of 24 to 149 °C and at various foam qualities (gas phase volume fraction). The foam was circulated at different flow rates and the differential pressure across each pipe section was recorded. All tests were conducted at 6.89 MPa. The foams displayed power-law fluid behavior in the shear rate range tested (100–5000 s−1), which is often experienced in the wellbore. Like its base liquid, polymer foam exhibited thermal thinning and a significant rheology change with temperature. Only high-quality foam (75%) at ambient temperature (24 °C) showed yielding behavior, which was measured in a pipe viscometer under static condition. The disappearance of yield stress at elevated temperature could be attributed to thermal thinning of the liquid phase that weakens the strength of bubble structure. Experimental data is used to develop new correlations to predict power-law fluid parameters as a function of temperature, base fluid properties, and foam quality. Moreover, the measurements are compared with the predictions of existing models, and discrepancies are observed, which could be attributed to the variation in foam generation technique, the nature and concentration of polymer, and the concentration of surfactant used in the experiments in which data was obtained to develop the models. Furthermore, annular pressure loss measurements obtained at low temperatures (24 and 79 °C) show predominantly good agreement with predictions of a hydraulic model that uses the new correlations. Discrepancies increased with temperature as the foam becomes unstable due to thermal thinning of the liquid film and subsequent weakening of bubble structure.

Research paper thumbnail of Sensitive acetone detection with a mid-IR interband cascade laser and wavelength modulation spectroscopy

OSA Continuum

An efficient method for the detection of acetone, an important biomarker in exhaled breath, by ut... more An efficient method for the detection of acetone, an important biomarker in exhaled breath, by utilizing wavelength modulation spectroscopy (WMS) with a mid-infrared distributed feedback interband cascade laser (DFB-ICL) is presented. The performance of the DFB-ICL laser is characterized, and its linewidth is measured to be mbox(3.mbox39pm0.mbox15)\mbox{(3}.\mbox{39} \pm 0.\mbox{15)}mbox(3.mbox39pm0.mbox15)(3.39±0.15) MHz by beating the output with an auxiliary mid-IR frequency comb over 50 ms. The measured asymmetric acetone absorption profile with the center wavelength around 3367 nm is fitted by the pseudo-Voigt function. The phase shift between the intensity and frequency modulations is determined and used for processing the results. The sensor is tested by performing measurements with calibration mixtures of acetone in nitrogen, and the detection limits of 0.58 ppm and 0.12 ppm were determined with 1 s and 60 s signal averaging times, respectively. Our work shows that wavelength modulation spectroscopy with a DFB-ICL laser complimented by a multipass cell for higher sensitivity can be efficiently used for acetone detection and is promising for sensitive breath analysis.

Research paper thumbnail of Sensitive Spectroscopic Analysis of Biomarkers in Exhaled Breath

International Journal of Thermophysics

AbstractWe have developed a novel optical setup which is based on a high finesse cavity and absor... more AbstractWe have developed a novel optical setup which is based on a high finesse cavity and absorption laser spectroscopy in the near-IR spectral region. In pilot experiments, spectrally resolved absorption measurements of biomarkers in exhaled breath, such as methane and acetone, were carried out using cavity ring-down spectroscopy (CRDS). With a 172-cm-long cavity, an efficient optical path of ~ 132 km was achieved. The CRDS technique is well suited for such measurements due to its high sensitivity and good spectral resolution. The detection limits for methane of ~ 8 ppbv and acetone of ~ 2.1 ppbv with spectral sampling of 0.005 cm−1 were achieved, which allowed to analyze multicomponent gas mixtures and to observe absorption peaks of 12CH4 and 13CH4. Further improvements of the technique have the potential to realize diagnostics of health conditions based on a multicomponent analysis of breath samples.

Research paper thumbnail of Rheology of a colloidal suspension of carbon nanotube particles in a water-based drilling fluid

Powder Technology

Abstract High-pressure and high-temperature rheology of a nanomud suspension is studied. The nano... more Abstract High-pressure and high-temperature rheology of a nanomud suspension is studied. The nanomud is prepared by dispersing a water-based drilling mud suspension with multi-walled carbon nanotubes (MWCNT). Effect of nanoparticle concentration, shear rate, pressure, and temperature are investigated. The pressure and temperature are independently varied from ambient conditions to 170 MPa and 180 °C respectively. The results presented show that the addition of CNT increases the viscosity of the drilling mud. A shear thinning non-Newtonian behavior is observed for the basemud and the nanomud samples at all pressures and temperatures. The basemud showed an increase in viscosity with an increase in pressure. However, with CNT particle addition this trend is observed to have reversed. For the basemud and the nanomud at lower concentrations, the viscosity values are observed to have initially increased with the increase in temperature and to have reduced beyond 100 °C. For a higher particle loading, a consistent decrease in viscosity with temperature is observed. The behavior of higher concentration nanomud samples with respect to pressure and temperature are seen to follow a similar trend to that of water. It is reasoned that an adequate addition of CNT nanoparticles helps retain the mud particles in a more homogenous and stable state, where they are held within the CNT chains. However, with further addition of CNT nanoparticles, the mud particles become agglomerated with the long chains of CNT, eventually separating water from the drilling fluid mixture.

Research paper thumbnail of Intelligent Tool To Design Drilling, Spacer, Cement Slurry, and Fracturing Fluids by Use of Machine-Learning Algorithms

SPE Drilling & Completion

Summary Design of drilling fluids, spacers, cement slurries, and fracturing fluids is often done ... more Summary Design of drilling fluids, spacers, cement slurries, and fracturing fluids is often done by trial and error in the laboratory. In the first step, the required properties of these fluids are categorized and then efforts will be started with a rough idea of the optimal composition. This first guess usually depends on the experience of the laboratory analyst or fluid engineer. Afterward, the trial-and-error testing starts, and it continues until the fluid design moves closer to the desired fluid criteria. There are several test data that would not be used in this method, and it is difficult to digest a large amount of information by the user. Trial and error could be time-consuming, very costly, and misleading. Today, there is a need for an intelligent system that uses all the available data (big data), even if the data sets are not close to the desired goal, and offers insights for fluid designs. This paper conducted a study on the application of machine-learning-based methodo...

Research paper thumbnail of Extension of filament propagation in water with Bessel-Gaussian beams

Research paper thumbnail of Advanced Fluid Data-Driven Analytics: One Step Closer to Well Integrity Excellence

International Petroleum Technology Conference, 2015

Research paper thumbnail of Effect of Low Elastic Wave Radiation on Fluid Percolation Through Fractured Media

73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011

During past few years, models for predicting the flow behavior under radiation of elastic waves h... more During past few years, models for predicting the flow behavior under radiation of elastic waves have been presented for non-fractured porous. However, little attention has been paid to mathematical modeling of this phenomenon in fractured media. In this work, the model presented by Pavel et.al is extended to fractured systems. Firstly, flow behavior of Bingham plastic crude oil is investigated in the fracture and secondly, acoustic waves role on capillary trapping is demonstrated. The results of mathematical model clarified that radiation of wave with low frequency and low intensity increases the flow rate and decreases the minimum pressure gradient required for flow of Bingham plastic fluids in fractured media. Besides, it is inferred that lower the saturation of oil in a two phase system in fracture, lower will the wave radiation be effectual. Further, it is shown that the effect of elastic wave is of less significance in higher pressure gradients. So it is revealed that low frequency wave technology would not be applicable in high pressure fractured reservoirs. The results of modeling presented in this work can be a path breaking to future studies in the field of fractured reservoirs acoustic stimulation.