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Technological frames
Published in Benjamin K. Sovacool, Visions of Energy Futures, 2019
But for readers unfamiliar with shale gas production, this all begs the question: what exactly is it? Natural gas comes in a variety of hydrocarbon mixtures located in a variety of geological settings. What engineers call “wet gas” has a higher proportion of heavier molecules like ethane, propane, butane, and pentane, and comes in a liquid state; “dry gas” comes in gaseous state and (in the current market) fetches a lower price. Most “wet” and “dry” gas comes from “plays” (the industry term for “fields”) composed of well-defined reservoirs with high rates of permeability. “Unconventional gas” refers to six types of gas plays where permeability is low: Coal-bed methane (contained in coal seams); tight gas (gas in low permeable formations); geo pressured gas (gas trapped in deep high-pressured reservoirs); gas hydrates (methane in the form of a crystalline solid that can be found in marine sediments); shale gas (gas trapped within shale formations of sedimentary rocks); and ultra-deep gas (often offshore reservoirs locked in high depths).21,22,23
Fuels commonly in use for clinker production
Published in Anjan Kumar Chatterjee, Cement Production Technology, 2018
Natural gas is the primary gaseous fuel obtained from underground strata either as such or associated with crude oil. When it occurs along with petroleum in oil wells, it is called “wet gas” and contains appreciable amounts of propane, butane, and other liquid hydrocarbons like pentanes, hexanes, etc. The wet gas is suitably treated to remove these hydrocarbons, which are used as LPG. When the gas is associated with crude oil, it is called “dry gas” and consists entirely of methane and ethane along with small amounts of impurities such as CO2, CO, H2S, N2, and inert gases. The approximate composition of natural gas is methane (CH4) (70–90%), ethane (C2H6) (5–10%), and hydrogen (H2) (3%). Besides these, CO and CO2 occur in small amounts. The calorific value varies from 12,000 to 14,000 kcal/m3. Natural gas is used both as domestic and industrial fuel, and its calorific value may be theoretically calculated from its composition as follows:
Feedstock Composition and Properties
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Natural gas liquids are the non-methane constituents such as ethane, propane, butane, and pentanes and higher molecular weight hydrocarbon constituents which can be separated as liquids during gas processing (Chapter 7). While natural gas liquids are gaseous at underground pressure, the molecules condense at atmospheric pressure and turn into liquids. The composition of natural gas can vary by geographic region, the geological age of the deposit, the depth of the gas, and many other factors. Natural gas that contains a lot of natural gas liquids and condensates is referred to as wet gas, while gas that is primarily methane, with little to no liquids in it when extracted, is referred to as dry gas.
Study on prediction model of liquid holdup based on back propagation neural network optimized by tuna swarm algorithm
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Rongge Xiao, Guoqing Liu, Dongrui Yi, Bo Liu, Qi Zhuang
For the study of gas-liquid two-phase flow in wet gas pipelines, scholars at home and abroad have carried out a large number of experiments, and obtained numerous and reliable liquid holdup data. Through literature investigation, the experimental data of liquid holdup of gas-liquid two-phase flow by some scholars were collected. The collected liquid holdup data were screened according to as follows: (1) Experimental data are independent of each other; (2) The liquid holdup data are measured after the pipe flow is stable (Chen 2017). According to the above criteria, 2141 independent experimental data samples were screened out. The data literature sources and experimental conditions for establishing the prediction model of liquid holdup in wet gas pipeline are shown in Table 1.
The origin and source of heavy oil and its control on oil and gas accumulation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Hongliang Zou, Hao Wu, Yanping Li, Zhengzhou Hu
In addition to the high-yield industrial oil flow, well D20 at the high structural position in the eastern section of Dinan uplift also obtained 0.0298 × 104m3 daily gas production. According to the composition characteristics of natural gas, methane content is 94.98%, heavy hydrocarbon (C2+) content is 1.96%, drying coefficient (C1/C1+) is 0.96, which belongs to typical dry gas. According to the theory of hydrocarbon generation, the reservoir should be associated with wet gas. Crude oil is associated with dry gas in this area, which indicates that the associated gas (wet gas) of crude oil has been lost, and then the reservoir is invaded by dry gas of a certain scale, resulting in the change of natural gas composition.
Influence of methane diffusion on geochemical characteristics of natural gas: a case study of the Shiqiantan area in Junggar Basin, China
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Zhaoyang Luo, Jungang Lu, Hongliang Zou, Yanping Li, Zhengzhou Hu
However, it should be noted that the drying coefficient of natural gas in this area is small, ranging from 0.74 to 0.86, which belongs to wet gas. This is obviously in contradiction with the results of carbon isotope analysis of natural gas composition and the hydrocarbon generation evolution stage (dry gas generation stage) of Carboniferous source rocks. The carbon isotope of alkane gas in the study area is similar to that of the natural gas in Beisantai uplift, showing a positive carbon isotope series of δ13C1< δ13C2< δ13C3< δ13C4 (Hu et al. 2019). The reason is that the methane content of natural gas in this area is low, which may be related to the preservation conditions. Under certain storage conditions, the methane molecular volume is smaller, and the dissipation capacity is higher than that of heavy hydrocarbons such as ethane, propane, and butane, which results in faster methane emission and smaller drying coefficient.