Low Specific Electrical Resistivity Research Articles

Features of isolation and nature of low-resistivity oil-saturated reservoirs of the Middle Jurassic deposits of the Akshabulak Central field of the South Torgai oil and gas basin

At the current stage of development of the oil and gas industry of our country, additional exploration of existing fields, understudied promising areas, identification of missed horizons, methods of evaluation and development of non-standard reservoirs are of particular relevance. Reservoirs with low specific electrical resistivity can be referred to non-standard reservoirs, and there are some difficulties in assessing hydrocarbon prospects of these reservoirs. Low resistivity reservoirs can be productive reservoirs with high residual water saturation as well as reservoirs for which generally accepted interpretation techniques are ineffective. Proper analysis of the reasons that lead to underestimation of the resistivity of productive reservoirs allows choosing the most effective interpretation methods. The article is devoted to the study of the features of reservoirs with low electrical resistivity, their nature and role in the process of fluid accumulation. The basic methods of identification of low resistivity zones in reservoir rocks, their physical and chemical characteristics that cause low resistivity, including mineralogical composition, saturation, porosity, permeability and pore space structure, are considered, and their influence on the filtration-capacitance characteristics is analyzed. Approaches to integrating data from various methods (geophysical and geological-technological studies, laboratory measurements) are described. Special attention is paid to the influence of low resistivity on the interpretation of data from geophysical methods. The results of the study have significant practical potential for optimization of field development.

Plasma-assisted deposition of indium tin oxide thin films by sublimation using an anodic vacuum arc discharge

With the anodic vacuum arc discharge as a method of physical vapor deposition (PVD) excellent properties of thin transparent conductive oxide films can be achieved, but the relations between the process parameters and the coating properties have been insufficiently described in the literature. This paper is intended to narrow this gap by investigations on indium tin oxide (ITO) thin films deposited on borosilicate glass sheets by sublimation of indium tin oxide (90:10) using an anodic vacuum arc. The arc discharge is based on a hot hollow cathode electron source and a special evaporator connected as anode. The concentration of the discharge onto the sublimating material is achieved by combining the magnetic fields of an axially symmetrical permanent magnet system and a solenoid coil. Coating rates of about 15 nm/s were achieved with an arc current of 60 A. Measurements with a planar Langmuir probe have shown that the vapor is highly ionized (about 95%). The discharge voltages are relatively low (< 60 V), so it can be assumed that the particle energies are correspondingly low. Substrate temperature (30–300 °C), oxygen gas flow (0–100 sccm) and gas pressure (0.04–0.4 Pa) were varied to study their influence on the thin film properties. Specific electrical conductivity, density and mobility of charge carriers, as well as optical properties were determined and compared with those of other PVD processes. Low specific electrical resistance of 1.8–2.0 x 10–4 Ω cm was reached at a substrate temperature of 200–300 °C independently of the pressure. The mean optical transmission (in the spectral range between 400 nm and 1100 nm) of 100 nm thick ITO films deposited at a temperature of 200 °C and at an optimized oxygen flow was determined to 84%. The roughness of the layers determined by atomic force microscopy is significantly lower than typically for magnetron sputtered films. At a pressure of 0.04 Pa, the crystalline bixbyite phase can already be detected at a coating temperature of approx. 30 °C, whereby the layer growth begins with the formation of an amorphous structure and changes to the crystalline phase with increasing layer thickness. At a temperature above 100 °C and low coating pressure the layers are completely crystalline. At a higher pressure the transition from amorphous to crystalline phase is shifted towards higher temperature. For lower oxygen flows the crystallites exhibit mainly a preferred (211) orientation. For higher oxygen flows the texture of crystallites is changed and the intensity of (440) and (622) is increased. The formation of these special crystallographic textures can probably explain the very low roughness values of the ITO layers measured by atomic force microscopy. The investigations have shown how the film properties can be adjusted by the process parameters and that the ITO sublimation using an anodic vacuum arc is suited very well for plasma assisted ITO thin film deposition.

PVP a binder for the manufacture of ultrathin ITO/polymer nanocomposite films with improved electrical conductivity

This paper presents the manufacture of ultrathin (<1 µm) transparent conductive indium tin oxide (ITO) films based on nanoparticulate ITO slurries by the profile rod technique using the binder polyvinyl pyrrolidone (PVP) as an organic additive. The influence of the slurry composition on the film thickness and the specific electrical resistance as well as the transmission of the dried films is evaluated. The organic solvent ethanol and different types of the PVP binder were tested for slurry preparation and layer performance. ITO green films with low specific electrical resistance of 3 Ω cm, 87 % inline transmission, and layer thicknesses of only 250 nm could be manufactured. Furthermore, the influence of heat treatments up to 400 °C on the electrical properties of the ITO films was evaluated.

Manufacture of sub-μm thin, particulate-based ITO layers by roller coating

This paper presents the development of nanoparticulate indium tin oxide (ITO) inks for the continuous manufacture of ultrathin (∼280nm) ITO layers on PET substrates by roller coating at very high coating speeds. Ethanol- and water-based ITO inks containing polyvinylpyrrolidone as binder were prepared and rheologically characterized. The influence of different ink compositions on coating properties was evaluated by the concept of the dimensionless capillary number Ca. The ITO films were characterized concerning optical and electrical properties in dependence on ink composition and coating parameters. The organic solvent ethanol could be replaced by water, being cheap and environmental friendly. These inks allow the manufacture of sub-μm thin ITO layers with high layer quality and low specific electrical resistance of 3Ωcm. Flexible and highly transparent ITO films with an inline-transmission of 88% in the regime of visible light which absorbed simultaneously up to 96% in the NIR region were produced.

Preparation and Sintering Behavior of the Tin‐Doped Indium Oxide Nanopowders

Tin‐doped indium oxide (ITO) nanopowders with 90±3 and 40±3 nm particle size were prepared by the urea‐based hydrothermal under a low‐pressure method. The sintering behavior of the as‐prepared ITO powder was studied at temperature from 1200° to 1500°C. The sintered ITO targets with large dimensions of 500 mm × 300 mm × 6 mm made from the as‐prepared 90 and 40 nm powders with w90 nm:w40 nm=70:30 had high density (99.7% of the theoretical density) and low specific electrical resistivity (120 μΩ·cm). The as‐prepared powders were favorable to commercial fabrication of the high‐density ITO targets.

Direct synthesis and inkjetting of silver nanocrystals toward printed electronics

Monolayer-protected silver nanoparticles were directly synthesized in a highly concentrated organicphase (>2 M) and then printed into conductive lines on polyimide by a drop-on-demand inkjetprinter. The fully organic phase system contains silver nitrate as a silver precursor,n-butylamine as a media dissolving silver salt, dodecanoic acid as a capping molecule,toluene as a solvent, and sodium borohydride as a reducing reagent. Even using onlygeneric chemicals, monodispersed silver nanocrystals with size of 7 nm were easilysynthesized at the 100 g scale in a 1 litre reactor. Hydrocarbon monolayer-protectedsilver nanocrystal showed excellent dispersion stability even at metal content>70 wt%. The silver ink with metal content of 33 wt% had a viscosity of 5.4 cP and surface tension of25 dyn cm−1. The silver ink was successfully inkjetted on variable substrates and then metallized at250 °C. The metallized silver patterns exhibited very low specific electrical resistance(6 µΩ cm)

Electroconducting homogeneous systems based on paired polymers

Chemical interaction in a solution of poly-1,1,2-trichlorobutadiene-1,3 and poly-1,2-dichlorobutadiene-1,3 with polyethyleneimine gives electroconducting paired polymers combining low specific electrical resistance ( ϱ v ∼ 10 5–10 7 Ω m ) with mechanical strength and elasticity ( σ r ∼ 20–40 MPa, ϵ ∼ 30–300%; E ∼ 500–1000 MPa). The maximum of the strength, elasticity and electrical conductivity of the polymer films corresponds to the equifunctional composition of the reacting polymers. The films obtained possess semiconductor properties.