Microscopic Dynamics of Water and Hydrocarbon in Shale-Kerogen Pores of Potentially Mixed Wettability

SPE Journal ◽  
2014 ◽  
Vol 20 (01) ◽  
pp. 112-124 ◽  
Author(s):  
Yinan Hu ◽  
Deepak Devegowda ◽  
Alberto Striolo ◽  
Anh Thi Van Phan ◽  
Tuan A. Ho ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Functional Groups ◽  
Hydraulic Fracture ◽  
Oil And Gas ◽  
Careful Consideration ◽  
Pore Morphology ◽  
Essential Information ◽  
Mixed Wettability ◽  
Slit Pore ◽  
Organic Pores

Summary Distribution of alkanes and water in organic pores of shale, referred to as kerogen, is essential information required for the estimation of shale-reservoir oil and gas in place, adsorption of hydrocarbon, and fate of hydraulic-fracture water. A practical modeling approach is presented for the proper description of the kerogen pore systems with different mixed wettability, surface roughness, tortuous paths, and material disorder. Three kerogen models—activated kerogen, kerogen free of activated sites, and graphite-slit pore—with proper surface-oxidized functional groups and high-temperature and pressure maturation are constructed by simulation. Distribution of octane and water in the organic pores of these models is predicted by molecular dynamics (MD) simulation. The results from our studies underscore the need for accurate characterization of kerogen pore systems in terms of the pore morphology, level of surface activation, and pore size. The improved kerogen models constructed to structurally resemble real organic materials have the potential to enable a better understanding of the placement, distribution, and trapping mechanisms of hydraulic-fracture water in shales. We demonstrate that depending on the maturity of the kerogen within organic-rich shales, organic pore systems may have mixed-wet characteristics and may create opportunities for water entrapment. The differences in the uptake of water are shown to be a function of the existence of oxygenated functional groups. In addition, the adsorption characteristics of alkanes in pores characterized by surface roughness are shown to be significantly different from those observed in the graphite-slit pore model. Our results indicate that careful consideration of the pore morphology is merited when estimating hydrocarbons in place with the Langmuir monolayer-adsorption theory.

scholarly journals ABOUT CHANGE OF HANDWRITING OF PERSONS THAT ARE IN THE STATE OF ALCOHOLIC INTOXICATION

2020 ◽  
Vol 11 (87) ◽  
Author(s):  
Оksana Rusova ◽  
◽  
Olga Samoilova ◽  
Keyword(s):  
Careful Consideration ◽  
Essential Information ◽  
Case File ◽  
Fast Pace ◽  
Expert’S Opinion ◽  
Psychological Attitude ◽  
The Law ◽  
Object Of Study ◽  
Concomitant Factors ◽  
Selection Of

This article focuses on the problematic issues that arise in the process of appointing a forensic handwriting examination, where the object of study are manuscripts performed in a state of intoxication. The reliability of the conclusions will largely depend on the correct quality and sufficient quantity of comparative material. This will be possible if the initiator of the study, after careful consideration of their work, qualitatively selects comparative material for the study. The purpose of this article is to further improve the purpose of forensic handwriting examination, the object of which is the study of manuscripts made in a state of intoxication, as well as to provide practical recommendations that will allow the initiators of the study to correctly select comparative material. Of particular importance in the conduct of forensic handwriting diagnostic examinations are information from the case file relating to the subject of examination, ie in the resolution, decision or statement must be indicated: first, it is information about the person - the actual or intended executor of the manuscript; second, essential information relating to the situation, the situation in which the manuscript in question was presumably performed, and in connection with it, the possible psychological attitude or emotional state of the person writing. When the initiator of the study informs the expert of the necessary information, he should not be afraid to "impose" a certain version, because the method of expert research is based on checking all the most likely alternatives (versions and counter version) and making decisions based only on objective data. Regarding the selection of comparative material provided for research in establishing whether a person was intoxicated, there are some peculiarities in the selection of experimental samples, because we cannot bring a person in such a state to take the necessary samples because the law prohibits harm to health, humiliation and infliction of moral suffering. They can be obtained without violating the law, by changing the condition, namely, you need to dictate the text at an extremely fast pace. The expert may also make a request, although the initiator of the study provided comparative material such as free, conditionally free and experimental samples, because there may be concomitant factors that the initiator did not take into account when selecting, such as experimental samples. The expert's request should be treated responsibly because the quality of the expert's opinion may depend on how well it is executed.

Applied Novel Quality Check Method for PVT Data with High Impurities Using Various Samples from Malaysian Fields

2021 ◽  
Author(s):  
Luky Hendraningrat ◽  
Intan Khalida Salleh
Keyword(s):  
Molecular Weight ◽  
Equation Of State ◽  
Gas Phase ◽  
Oil And Gas ◽  
Comprehensive Evaluation ◽  
Gas Condensate ◽  
Fluid Composition ◽  
Essential Information ◽  
Pvt Data ◽  
Wide Range

Abstract PVT analysis of reservoir fluid samples provides essential information for determining hydrocarbon in place, depletion strategy, and hydrocarbon flowability. Hence, quality checking (QC) is necessary to ensure the best representative sample for further analysis. Recently, a novel tool based on Equation of State (EOS) was introduced to tackle the limitation of the Hoffmann method for surface samples with high impurities and heavier components. This paper presents comprehensively evaluating a novel EOS-based method using various PVT data from Malaysian fields. Numerous PVT separator samples from 30 fields with various reservoir fluids (Black Oil, Volatile, and Gas Condensate) were carried out and evaluated. The impurities contain a wide range of up to 60%. The 2-phase P-T (pressure and temperature) diagram of each oil and gas phase before recombination was calculated using PVT software based on Equation of State (EOS). The 2-phase P-T diagram was created and observed the intersection point as calculated equilibrium at separator conditions. Once it is observed and compared with written separator condition in the laboratory report and observed its deviation. Eventually, the result will be compared with the Hoffmann method. The Hoffmann method is well-known as a traditional QC method that was initially developed using gas condensate PVT data to identify possible errors in measured separator samples. If the sample has high impurities and/or heavier components, the Hoffmann method will only show a straight line to the lighter components and those impurities and heavier components will be an outlier that engineers will misinterpret that it has errors and cannot be used for further analysis such PVT characterization. The QC using EOS-based were conducted using actual fields data. It shows potential as novel QC tools but observed only less than 10% of data with complete information that can meet intersection points located precisely similar with reported in the laboratory. There is some investigation and evaluation of the EOS-based QC method. First, most of the molecular weight of the heavier fluid composition of gas and oil phase was not reported or used assumptions especially when its mole fraction is not zero. Second, properties of heavier components of the oil phase (molecular weight and specific gravity) were not measured and assumed similar as wellstream. Third, pressure and temperature data are inconsistent between the oil and gas phase at the separator condition. This study can provide improvement in laboratory measurement quality and help engineers to have a better understanding of PVT Report, essential data requirements, and assumptions used in the laboratory. Nevertheless, the Hoffmann method can be used as an inexpensive QC tool because it can be generated in a spreadsheet without a PVT software license. Both combination techniques can provide a comprehensive evaluation for separator samples with high impurities before identifying representative fluid for further analysis.

scholarly journals Spatially resolved wettability measurements using nmr wettability index

2019 ◽  
Vol 89 ◽  
pp. 03001
Author(s):  
M. J. Dick ◽  
D. Veselinovic ◽  
D. Green
Keyword(s):  
Oil And Gas ◽  
Gas Reservoirs ◽  
Bulk Oil ◽  
Partially Saturated ◽  
Spatially Resolved ◽  
Industry Standard ◽  
Least Squares Fit ◽  
Mixed Wettability ◽  
Petrophysical Parameter ◽  
Oil Water

Wettability is a crucial petrophysical parameter for determining accurate production rates in oil and gas reservoirs. However, industry standard wettability measurements (Amott Test and USBM) are expensive and time consuming. It is known that NMR response varies as a function of wettability change in rock core plug samples. This information was used to develop an NMR wettability index (NWI) based on T2 distributions. This NWI is capable of measuring changes in wettability as a function of oil/water saturations unlike traditional methods which are based on measurements at Swi and Sor only. In addition, these oil/water saturations are determined without the aid of any special oil or brine, such as D2O. This allows the NMR method to nondestructively monitor changes in wettability in real time (i.e. during a flooding experiment or an aging procedure). In this work, we have coupled this T2-based NWI to spatially resolved T2 NMR measurements to monitor changes in wettability and saturation along rock core plugs. In order to derive an NMR wettability index, NMR T2 spectra of 100% brine saturated, 100% oil saturated, bulk oil and bulk brine are needed. These spectra are then mixed to give a predicted T2 spectrum which is compared (via a least squares fit) to a T2 spectrum recorded from a sample partially saturated with both water and oil and whose wettability is to be determined. For initial testing, three sandstone samples were employed along with 2% KCl brine and dodecane. To achieve sample states of mixed wettability, 100% brine saturated samples had dodecane pushed into them via centrifugation. Centrifugation at different speeds resulted in samples of varying bulk and spatial wettabilities from which NWI parameters and oil/water saturations were determined. The bulk wettabilities were compared to measurements done using the standard Amott test and oil/water saturations were confirmed by repeating experiments using NMR invisible D2O.

Surface Modification of a-C:H(N) Thin Films by Plasma Treatment

2005 ◽  
Vol 11 (S03) ◽  
pp. 162-165 ◽  
Author(s):  
L. von Mühlen ◽  
R. A. Simao ◽  
C. A. Achete
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Optical Properties ◽  
Surface Modification ◽  
Surface Chemistry ◽  
Plasma Treatment ◽  
Surface Properties ◽  
Functional Groups ◽  
Material Properties ◽  
Modify Surface

Surface chemistry and topography of materials are generally preponderant factors in a series of material properties, such as adhesion, wettability, friction and optical properties [1]. Wettability of films, for example, can be altered significantly by modifying its surface roughness and also by incorporating functional groups. Plasma treatment is a powerful and versatile way to modify surface properties of amorphous nitrogen-incorporated carbon thin films (a-C:H(N)) and obtain materials with improved properties, once it is possible to modify the surfaces in a controlled way by specific settings of plasma conditions. [2 - 4]

Some challenges in hydraulic fracturing of tight gas reservoirs: an experimental study

2011 ◽  
Vol 51 (1) ◽  
pp. 499 ◽  
Author(s):  
Vamegh Rasouli ◽  
Mohammad Sarmadivaleh ◽  
Amin Nabipour
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Oil And Gas ◽  
Interaction Mechanism ◽  
Natural Fracture ◽  
Gas Reservoirs ◽  
Tight Sandstone ◽  
True Triaxial ◽  
Rock Types ◽  
Interface Parameters

Hydraulic fracturing is a technique used to enhance production from low quality oil and gas reservoirs. This approach is the key technique specifically in developing unconventional reservoirs, such as tight formations and shale gas. During its propagation, the hydraulic fracture may arrive at different interfaces. The mechanical properties and bounding quality of the interface as well as insitu stresses are among the most significant parameters that determine the interaction mechanism, i.e. whether the hydraulic fracture stops, crosses or experiences an offset upon its arrival at the interface. The interface could be a natural fracture, an interbed, layering or any other weakness feature. In addition to the interface parameters, the rock types of the two sides of the interface may affect the interaction mechanism. To study the interaction mechanism, hydraulic fracturing experiments were conducted using a true triaxial stress cell on two cube samples of 15 cm. Sample I had a sandstone block in the middle surrounded by mortar, whereas in sample II the location of mortar and tight sandstone blocks were changed. The results indicated that besides the effect of the far field stress magnitudes, the heterogeneity of the formation texture and interface properties can have a dominant effect in propagation characteristics of an induced fracture.

scholarly journals Carbon Dioxide Capture in Homogeneous and Heterogeneous Surfaces of Porous Silica Glass

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1260
Author(s):  
Chontira Boonfung ◽  
Chaiyot Tangsathitkulchai ◽  
Atichat Wongkoblap
Keyword(s):  
Carbon Dioxide ◽  
Functional Groups ◽  
Adsorption Isotherms ◽  
Silica Glass ◽  
Surface Defects ◽  
Porous Silica ◽  
Surface Heterogeneity ◽  
Slit Pore ◽  
Porous Silica Glass ◽  
Carbon Dioxide Co2

Experimental and simulation studies for carbon dioxide (CO2) adsorption on porous silica glass were performed to reveal how surface heterogeneity can affect the adsorption mechanism of CO2. In performing the simulation, the structure of porous silica glass was modeled as a slit pore consisting of parallel walls of connected SiO4 units. The adsorption isotherms of CO2 at 283 K were generated for a series of pore widths using a Monte Carlo ensemble. The defective surfaces created by random removal of surface atoms and the surfaces containing hydroxyl functional groups were chosen to represent the surface heterogeneity for the simulation tasks. The isotherms derived for the defective surfaces showed a rapid adsorption at low pressures because of the stronger interaction between the rough nonuniform surfaces and CO2 molecules. For the role of surface functional groups, the adsorption isotherms dramatically increased with an increasing number of functional groups. The amount of CO2 adsorbed for randomly placed functional groups was greater than that for the presence of functional groups at the pore edges. The proper control of surface heterogeneity by manipulating both the amounts of hydroxyl surface groups and surface defects should help enhance the efficient capture of CO2 in porous silica glass.

A fractal approach for surface roughness analysis of laboratory hydraulic fracture

2021 ◽  
Vol 85 ◽  
pp. 103703
Author(s):  
Abbas Movassagh ◽  
Manouchehr Haghighi ◽  
Xi Zhang ◽  
Dane Kasperczyk ◽  
Mohammad Sayyafzadeh
Keyword(s):  
Surface Roughness ◽  
Hydraulic Fracture ◽  
Fractal Approach ◽  
Roughness Analysis

Adhesion Properties of Cellulose Films

1999 ◽  
Vol 586 ◽  
Author(s):  
Xiujuan Zhang ◽  
Raymond. A. Young
Keyword(s):  
Surface Roughness ◽  
Plasma Treatment ◽  
Functional Groups ◽  
Adhesion Force ◽  
Oxygen Plasma Treatment ◽  
Base Interaction ◽  
Adhesion Properties ◽  
Oh Groups ◽  
Cellulose Films ◽  
Afm Tips

ABSTRACTThe adhesion properties were evaluated for untreated and modified cellulose (cellophane) films. Several functional groups were introduced on the film surfaces by plasma based treatments. All the films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM was employed to study the adhesion properties using both standard silicon nitride tips as well as self-assembled monolayer (SAM) modified gold coated tips containing a variety of specific functional groups. The acetone extracted cellulose films, which are rich in –OH groups, were used as substrates. The adhesion force detected with –COOH terminated AFM tips (∼ 34.8 nN) was much larger than that with –CH3 terminated AFM tips (∼16.7 nN), which was attributed to the hydrogen bonding between –COOH and –OH functional groups. The adhesion force of –NH2 terminated AFM tips on the acetone extracted cellulose film was higher at 42.92 nN. However, after surface modification of the cellulose films with argon and oxygen based plasma treatments, the adhesion force were decreased to 17.4 and 19.4 nN respectively as a result of greatly enhanced surface roughness. Hydrazine plasma treatment also was used to introduce –NH2 groups on the film surfaces, and the strongest adhesion behavior was observed with AFM tips terminated with -COOH groups on the aminated film due to acid-base interaction. The argon and oxygen plasma treatment greatly increased the surface roughness, resulting in poor adhesion properties. Both surface roughness and chemical modification of the cellophane films affected the adhesion properties as measured by AFM force curves.

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