Shale gas

It specifically refers to unconventional gas found in shale. Shale is also a type of dense rock, so it can be classified as gas in dense gas reservoirs as well. Only North America (mainly the United States) has achieved success in industrial development. It originates from the Devonian shales of the Appalachian Basin; it is dark brown and black in color, rich in organic matter, and capable of producing large amounts of gas. The reservoir space is dominated by fractures and can store gas in the form of dissolved gas in water; it features low (negative) pressure and low saturation (around 30%), resulting in low production. However, higher yields can be achieved in fracture-developed zones, and improvement measures such as downhole explosions and fracturing also yield good results. By the mid-1990s, it had expanded to the Michigan and Illinois basins; the reservoir layers extended to the Lower Carboniferous shales, and production reached 8.4 billion cubic meters. Its resource volume can reach trillions of cubic meters. Shale gas is natural gas extracted from shale layers, primarily found in dark shales or high-carbon shales. It exists in these formations either in adsorbed form or as free gas within interlayers of mudstone, high-carbon mudstone, shale, and sandy rocks. It can be generated at various stages of organic formation; about 50% of it exists in a free phase within fractures, pores, and other storage spaces, while about 50% is present in adsorbed form on kerogen, clay particles, and pore surfaces. A very small amount is stored in dissolved form within kerogen, asphaltenes, and oil. Shale gas is also found in interlayered formations such as sandstone, sandy mudstone, argillaceous sandstone, and even sandstone layers. After its formation, it accumulates in the source rock layers, exhibiting a typical in-situ accumulation pattern, which differs significantly from that of oil shale, oil sands, and tar. Unlike conventional reservoir gas fields, shale serves as both the source rock for natural gas formation and the reservoir and cap rock for its accumulation and preservation. Therefore, black shales with high organic matter content, high-carbon mudstones, and similar formations are often the best conditions for the development of shale gas. The development of shale gas holds great geological significance; it is present in almost all basins. However, due to differences in burial depth, gas saturation, and other factors, it possesses varying degrees of industrial value. Traditional Chinese concepts such as shale fracture gas, shale oil and gas reservoirs, mudstone fracture oil and gas reservoirs, and fractured oil and gas reservoirs are roughly equivalent to these, but they do not take into account the adsorption mechanism nor the original properties of the natural gas; instead, they are essentially understood as free-phase oil and gas accumulated in the fractures of shales. Therefore, it belongs to shale gas in an incomplete sense. Therefore, the concept of fractured oil and gas reservoirs in China’s shales is not entirely identical to the current understanding of shale gas in the United States; there are significant differences in aspects such as the hydrocarbon composition, storage phase state, source characteristics, and elemental makeup. The shale gas resources in our main basins and regions amount to approximately 15 trillion to 30 trillion cubic meters, which is roughly equivalent to the 28.3 trillion cubic meters in the United States, holding great economic value. On the other hand, a long production cycle is also a notable feature of shale gas. The operational life of shale gas fields can generally range from 30 to 50 years, or even longer. According to the latest data from the U.S. Geological Survey, the extraction lifespan of the Barnett shale gas field in the Fort Worth Basin in the United States can range from 80 to 100 years. A long mining life means a high value that can be exploited, which in turn determines its development potential. It is mainly hydrocarbons; the specific composition varies, and it refers to free natural gas

Reply to 2# TH373637: Are there detailed ingredient data?

Components and prices, the possibility of replacing natural gas in China

It varies depending on location, area, and depth; mainly it’s methane, with the remainder being hydrocarbons

As far as I know, in some lower-quality conventional natural gas, the proportion of methane is even below 60%, while the proportion of carbon dioxide is quite high. Does anyone know anything about shale gas?

This post was last edited by Chemical Gas Purification on 2013-3-15 07:57. I would like to ask everyone: can gasoline be separated from shale gas?