Formulation effects on the lubricity of o/w emulsions used as oil well working fluids

In oil well drilling, completion, and maintenance operations, the rotating pipe bears against the side of the hole at numerous points, giving rise to two main friction manifestations known as torque and drag. Torque refers to the pipe resistance to rotation and drag to hoisting and lowering. Excessive torque and drag can cause unacceptable loss of power making oil well operations less efficient, especially in high-angle and extended-reach wells. In these cases, lubricity becomes one of the main functions of the fluid. In the oil industry, there are oil well working fluids of different nature, classified according to the external phase as water-based fluids (WBFs), oil-based fluids, and pneumatic or gas-based fluid systems. Within WBFs, there are oil-in-water (O/W) emulsions, developed as a technological solution for oil well operations in low-pressure reservoirs. In this work, tribological properties of O/W emulsions have been studied as a function of their physicochemical formulation, especially oil type (nonaromatic mineral oil [NAM-oil], diesel) and surfactant concentration (1, 2% w/v) along with the oil/water ratio (70/30, 50/50) as formulation variables. The lubrication performance was established by measuring the coefficient of friction (CF), and optical microscopy imaging in conjunction with optical surface profilometry was used to evaluate antiwear properties. Additionally, contact angle measurements were performed to correlate the wettability phenomenon with the lubricity of O/W emulsions. Based on the results, it was established that with the surfactants mixture used in this study, the oil type does not have a significant effect on the CF of O/W emulsions, due to the similar wettability behavior observed at the metal surface. However, NAM-oil/W emulsions have better antiwear properties than the diesel/W emulsions. Also, the lubricity performance and antiwear properties of O/W emulsions are affected by oil/water ratio and surfactants mixture concentration, showing a systemic interaction between these two parameters

Formulation effects on the lubricity of o/w emulsions used as oil well working fluids

In oil well drilling, completion, and maintenance operations, the rotating pipe bears against the side of the hole at numerous points, giving rise to two main friction manifestations known as torque and drag. Torque refers to the pipe resistance to rotation and drag to hoisting and lowering. Excessive torque and drag can cause unacceptable loss of power making oil well operations less efficient, especially in high-angle and extended-reach wells. In these cases, lubricity becomes one of the main functions of the fluid. In the oil industry, there are oil well working fluids of different nature, classified according to the external phase as water-based fluids (WBFs), oil-based fluids, and pneumatic or gas-based fluid systems. Within WBFs, there are oil-in-water (O/W) emulsions, developed as a technological solution for oil well operations in low-pressure reservoirs. In this work, tribological properties of O/W emulsions have been studied as a function of their physicochemical formulation, especially oil type (nonaromatic mineral oil [NAM-oil], diesel) and surfactant concentration (1, 2% w/v) along with the oil/water ratio (70/30, 50/50) as formulation variables. The lubrication performance was established by measuring the coefficient of friction (CF), and optical microscopy imaging in conjunction with optical surface profilometry was used to evaluate antiwear properties. Additionally, contact angle measurements were performed to correlate the wettability phenomenon with the lubricity of O/W emulsions. Based on the results, it was established that with the surfactants mixture used in this study, the oil type does not have a significant effect on the CF of O/W emulsions, due to the similar wettability behavior observed at the metal surface. However, NAM-oil/W emulsions have better antiwear properties than the diesel/W emulsions. Also, the lubricity performance and antiwear properties of O/W emulsions are affected by oil/water ratio and surfactants mixture concentration, showing a systemic interaction between these two parameters

Space-time inhomogeneity, anisotropy and gravitational collapse

We investigate the evolution of non-adiabatic collapse of a shear-free spherically symmetric stellar configuration with anisotropic stresses accompanied with radial heat flux. The collapse begins from a curvature singularity with infinite mass and size on an inhomogeneous space-time background. The collapse is found to proceed without formation of an even horizon to singularity when the collapsing configuration radiates all its mass energy. The impact of inhomogeneity on various parameters of the collapsing stellar configuration is examined in some specific space-time backgrounds.Comment: To appear in Gen. Relativ. Gra

Hypogene Calcitization: Evaporite Diagenesis in the Western Delaware Basin

Evaporite calcitization within the Castile Formation of the Delaware Basin is more widespread and diverse than originally recognized. Coupled field and GIS studies have identified more than 1000 individual occurrences of calcitization within the Castile Formation outcrop area, which includes both calcitized masses (limestone buttes) and laterally extensive calcitized horizons (limestone sheets). Both limestone buttes and sheets commonly contain a central brecciated zone that we attribute to hypogene dissolution. Lithologic fabric of calcitized zones ranges from little alteration of original varved laminae to fabrics showing extensive laminae distortion as well as extensive vuggy and open cavernous porosity. Calcitization is most abundant in the western portion of the Castile outcrop region where surface denudation has been greatest. Calcitization often forms linear trends, indicating fluid migration along fractures, but also occurs as dense clusters indicating focused, ascending, hydrocarbon-rich fluids. Native sulfur, secondary tabular gypsum (i.e. selenite) and hypogene caves are commonly associated with clusters of calcitization. This assemblage suggests that calcium sulfate diagenesis within the Castile Formation is dominated by hypogene speleogemesis

Search for the Chiral Magnetic Effect in Au+Au collisions at sNN=27\sqrt{s_{_{\rm{NN}}}}=27 GeV with the STAR forward Event Plane Detectors

A decisive experimental test of the Chiral Magnetic Effect (CME) is considered one of the major scientific goals at the Relativistic Heavy-Ion Collider (RHIC) towards understanding the nontrivial topological fluctuations of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is expected to result in a charge separation phenomenon across the reaction plane, whose strength could be strongly energy dependent. The previous CME searches have been focused on top RHIC energy collisions. In this Letter, we present a low energy search for the CME in Au+Au collisions at $\sqrt{s_{_{\rm{NN}}}}=27$ GeV. We measure elliptic flow scaled charge-dependent correlators relative to the event planes that are defined at both mid-rapidity $|\eta|<1.0$ and at forward rapidity $2.1 < |\eta|<5.1$. We compare the results based on the directed flow plane ($\Psi_1$) at forward rapidity and the elliptic flow plane ($\Psi_2$) at both central and forward rapidity. The CME scenario is expected to result in a larger correlation relative to $\Psi_1$ than to $\Psi_2$, while a flow driven background scenario would lead to a consistent result for both event planes[1,2]. In 10-50\% centrality, results using three different event planes are found to be consistent within experimental uncertainties, suggesting a flow driven background scenario dominating the measurement. We obtain an upper limit on the deviation from a flow driven background scenario at the 95\% confidence level. This work opens up a possible road map towards future CME search with the high statistics data from the RHIC Beam Energy Scan Phase-II.Comment: main: 8 pages, 5 figures; supplementary material: 2 pages, 1 figur

Temperature Sensor Based On Functionalized Polymeric Fiber

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Polymeric optical fibers (POF) are processed at low temperatures allowing functionalizing the raw material prior to fiber fabrication. With this in mind POF or microstructure POF doped fibers can be prepared. In this work an extruded solid Poly(methyl methacrylate) (PMMA) fiber containing the complex diaqua(tristhenoyltrifluoroacetonate) europium(III) [Eu(tta)3(H2O)3] was prepared and characterized as a temperature sensor. The emission lifetime of the 5D0 state of the europium(III) ion was measured in the temperature range from 10°C to 60°C. The results show a linear and negative dependence between the emission lifetime and the fiber temperature with a proportional coefficient of (-2.27 ± 0.01) microseconds/°C. This represents a reduction of about 30% of the emission lifetime when changing 50°C the fiber temperature.328330CNPq,COPPE/UFRJ - Universidade Federal do Rio de Janeiro,et al.,FAPERJ,KDPOF,LIF - Laboratorio de Instrumentacao e FotonicaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Lourenço, A.V.S., Kodaira, C.A., Ramos-Sanchez, E.M., Felinto, M.C.F.C., Goto, H., Gidlund, M., Malta, O.L., Brito, H.F., Luminescent material based on the [Eu(TTA)3(H2O)2] complex incorporated into modified silica particles for biological applications (2013) Journal of Inorganic Biochemistry, 123, pp. 11-17Sholes, R.R., Small, J.G., Fluorescent decay thermometer with biological applications (1980) Review of Scientific Instruments, 51 (7), pp. 882-884Sinha, S.P., Complexes of the rare earths (1966), Pergamon Press Lt

Formulation effects on the lubricity of o/w emulsions used as oil well working fluids

In oil well drilling, completion, and maintenance operations, the rotating pipe bears against the side of the hole at numerous points, giving rise to two main friction manifestations known as torque and drag. Torque refers to the pipe resistance to rotation and drag to hoisting and lowering. Excessive torque and drag can cause unacceptable loss of power making oil well operations less efficient, especially in high-angle and extended-reach wells. In these cases, lubricity becomes one of the main functions of the fluid. In the oil industry, there are oil well working fluids of different nature, classified according to the external phase as water-based fluids (WBFs), oil-based fluids, and pneumatic or gas-based fluid systems. Within WBFs, there are oil-in-water (O/W) emulsions, developed as a technological solution for oil well operations in low-pressure reservoirs. In this work, tribological properties of O/W emulsions have been studied as a function of their physicochemical formulation, especially oil type (nonaromatic mineral oil [NAM-oil], diesel) and surfactant concentration (1, 2% w/v) along with the oil/water ratio (70/30, 50/50) as formulation variables. The lubrication performance was established by measuring the coefficient of friction (CF), and optical microscopy imaging in conjunction with optical surface profilometry was used to evaluate antiwear properties. Additionally, contact angle measurements were performed to correlate the wettability phenomenon with the lubricity of O/W emulsions. Based on the results, it was established that with the surfactants mixture used in this study, the oil type does not have a significant effect on the CF of O/W emulsions, due to the similar wettability behavior observed at the metal surface. However, NAM-oil/W emulsions have better antiwear properties than the diesel/W emulsions. Also, the lubricity performance and antiwear properties of O/W emulsions are affected by oil/water ratio and surfactants mixture concentration, showing a systemic interaction between these two parameters

The orbital harderian gland of the male atlantic bottlenose dolphin (Tursiops truncatus): A morphological study

Summary The ultrastructure of the Atlantic Bottlenose dolphin Harderian gland (HG) has been described but some questions remain unanswered. The purpose of this work was to define the gland's structure, ultrastructure and the differences between cells (types I and II) of the male dolphin using optic, fluorescence and electron transmission microscopy. Three different cells were observed under optic and fluorescence microscopic examination, while only two cell types (types I and II) were distinguished by electron transmission microscopy. Type I (oval nuclear envelope) exhibited three different cell populations and type II (indented nuclear envelope) exhibited two different cell populations. Although, we observed both types of vesicles in both types of cells they differed, principally, in quantity. The glands also possessed prominent duct systems, with three orders of complexity. The dolphin orbital HG appears to function as a mixed heterologous gland with two types of cells that exhibit both types of vesicles and other distinguishable differences. © 2007 The Authors. Journal compilation 2007 Blackwell Verlag