Search

In order to ensure the most complete recovery of hydrocarbons and to minimize costs in the production process, it is necessary to control the development of an oil field, even during production, through various geological and technological measures. In terms of the volume of additional oil extracted through the implementation of geological and technological measures, hydraulic fracturing (HF) operations occupy the top positions. This paper describes a modified method for accounting for hydraulic fractures in a geological and technological model of a hydrocarbon field. The method makes it possible to perform all calculations related to the modeling of fractures in the pre-processing phase and to use its results as input data for the hydrodynamic simulator. An example of the calculation on a real development object is given. The analysis of the results showed the correctness of this method. The geological and hydrodynamic model provided a satisfactory reproduction of the development history for the oil field under study. The predicted flow rates and bottomhole pressures of the wells were close to the actual values. The error in annual oil and fluid rates is no greater than 3 %. The results of the calculations can serve as indirect confirmation of the hypothesis of spontaneous growth of hydraulic fracturing cracks in injection wells. In fact, by increasing the half-length of the hydraulic fractures in the injection wells in the model to 250 m, the discrepancy between the calculated and actual bottomhole pressures was reduced to fractions of a percent. The half-length of the fracture was 70 - 140 m and the half-opening was 1.2 - 2.5 mm. The average permeability of the proppant package in the crack is 220 d. The calculated skin factor for the design wells according to proposed model was −4.58. HIGHLIGHTS Various geological and technological measures are taken to control the development of an oil field, even during production Enhancing oil recovery by accounting for hydraulic fractures in a geological and technological model of a hydrocarbon field Evidence of spontaneous crack growth in injection wells of hydrocarbon fields in indirect confirmation of the hypothesis of hydraulic fracturing GRAPHICAL ABSTRACT

We apply phosphorus-doped silicon nitride (SiNX:P) layers on the front surface of p-type Czochralski-grown silicon (Cz-Si) passivated emitter and rear cells (PERC). The layers are formed using industrial-type plasma-enhanced chemical vapor deposition. They provide excellent surface passivation with implied open-circuit voltages text{i}V{text{OC}} up to 695 mV and similar optical properties as conventional undoped SiNX anti-reflection layers with text{i}V{text{OC}} peaking at 685 mV. The emitter dark saturation current density at the passivated textured surface is j{rm 0e} â 40 fA/cm² for a lowly-doped emitter with sheet resistance R{text{sh}} â 160 Ω/sq. For realizing laser-doped selective emitters (LDSE), local laser processing is applied to introduce additional dopants from the SiNX:P layer into the silicon. Thereby, highly doped areas are formed in which R{text{sh}} is decreased down to 55 Ω/sq. We refer to this as the nPassDop approach, which provides both lo cal high doping and local structuring of the anti-reflection coating in a single process step. Low contact resistivity of around 1.5 mΩcm2 is measured for screen-printed and fired silver contacts on the locally laser-doped areas. A first proof of concept of large-area p-type Cz-Si PERC solar cells with front side text{SiN}{text{X}}text{:P} passivation and LDSE structure yield energy conversion efficiencies up to 20.9%.

GreenFlexJET is an EU funded project that is developing a pre-commercial demonstration plant to produce sustainable aviation fuel from waste vegetable oil and organic solid waste biomass. The plant will demonstrate the integration of the SABR-TCR technology i.e., transesterification (TRANS), hydrodeoxygenation (HDO) and hydrocracking/isomerisation (HC) and Thermo-Catalytic Reforming (TCR®) combined with hydrogen separation through pressure swing adsorption (PSA) to produce a fully equivalent jet fuel (compliant with ASTM D7566 Standards). The project plant installed close to waste sources and product off-takers at Gloucestershire Park of Science and Technology, Berkeley (UK) will produce 1,200 tonnes of jet fuel from around 3,600 tonnes of waste vegetable oil and 3,500 tonnes of dried organic waste per year. The demonstration plant will provide a real example of how sustainable aviation biofuels can be produced economically on a large scale, whilst simultaneously addressing social and environmental sustainability., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 902-905

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottom hole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%.Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

The efficiency of gas injection for developing terrigenous deposits within a multilayer producing object is investigated in this article. According to the results of measurements of the 3D hydrodynamic compositional model, an assessment of the oil recovery factor was made. In the studied conditions, re-injection of the associated gas was found to be the most technologically efficient working agent. The factors contributing to the inefficacy of traditional methods of stimulating oil production such as multistage hydraulic fracturing when used to develop low-permeability reservoirs have been analysed. The factors contributing to the inefficiency of traditional oil-production stimulation methods, such as multistage hydraulic fracturing, have been analysed when they are applied to low-permeability reservoirs. The use of a gas of various compositions is found to be more effective as a working agent for reservoirs with permeability less than 0.005 μm2. Ultimately, the selection of an agent for injection into the reservoir should be driven by the criteria that allow assessing the applicability of the method under specific geological and physical conditions. In multilayer production objects, gas injection efficiency is influenced by a number of factors, in addition to displacement, including the ratio of gas volumes, the degree to which pressure is maintained in each reservoir, as well as how the well is operated. With the increase in production rate from 60 to 90 m3 / day during the re-injection of produced hydrocarbon gas, this study found that the oil recovery factor increased from 0.190 to 0.229. The further increase in flow rate to 150 m3 / day, however, led to a faster gas breakthrough, a decrease in the amount of oil produced, and a decrease in the oil recovery factor to 0.19. Based on the results of the research, methods for stimulating the formation of low-permeability reservoirs were ranked based on their efficacy.

Fragestellung: Unterarmfrakturen sind eine der häufigsten Verletzungen bei Kindern. In den letzten Jahren konnte eine Tendenz zur operativen Versorgung durch geschlossene Reposition und Stabilisierung mittels elsatisch-stabiler intramedullärer Nagelung (ESIN) festgestellt werden. Trotz nur [zum vollständigen Text gelangen Sie über die oben angegebene URL]