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Exploration and Geology
Published in Nwanosike-Warren Quinta, Oil and Gas Engineering for Non-Engineers, 2022
Shale is a laminated sedimentary rock, which comprises fine silt, clay, and other minerals. While oil and gas are normally produced from reservoir rock, in shale reservoirs, the shale oil and gas are produced from the source rock. The shale rock acts as a source, reservoir, and seal. This creates some challenges since source rock has very low permeability and is generally very thin.
Operations for Gas Handling (Conditioning), Treatment, and Separation of NGL
Published in Hussein K. Abdel-Aal, Economic Analysis of Oil and Gas Engineering Operations, 2021
Shale gas is defined as natural gas from shale formations, i.e., natural gas trapped within shale (fine grained sedimentary rocks) formations. Shale has low matrix permeability to allow significant fluid flow to well bore; therefore, commercial production requires mechanically increasing permeability. Shale gas reserves are known for long but natural fracture technology used earlier was uneconomical to produce shale gas. The recent developments in horizontal drilling and hydraulic fracturing (called fracking) made it viable. Mitchell energy, a Texas gas company, first achieved economical shale gas fracture in 1998. Shale gas is currently under evolutionary stage and so far is largely confined to North America. The complete technology and economic factors are yet to get matured. Several high profile shale gas drilling efforts in Europe have already failed.
Water Use and Availability
Published in Frank R. Spellman, The Science of Water, 2020
Much of the projected increase in shale-gas production is contingent on the use of hydraulic fracturing, a process that is under scrutiny due to environmental concerns, mainly the potential contamination of groundwater resources. The greatest concern is that fracturing may allow gas and other contaminants, such as those in the fracturing fluid, to seep into underground sources of drinking water. The EPA is now investigating these issues, conducting a study that is not expected to be completed until 2014; however, the agency recently released a draft report detailing tests done at hydraulic fracturing sites in Wyoming’s Pavilion gas field. In this report, the EPA noted that domestic groundwater sources located near hydraulic fracturing sites had a high number of organic and inorganic contaminants associated with hydraulic fracturing (DiGulio et al., 2011). While these findings are not definitive and the Agency has reached no conclusions about the safety of hydraulic fracturing, the result suggests that environmental externalities associated with the production of shale gas may, at least in some cases, affect the use of groundwater for other purposes.
Temperature distribution of shale oil wellbore considering oil-based mud and formation fluid displacement
Published in Journal of Dispersion Science and Technology, 2023
Wen Yin, Yun Lei, Song Deng, Meng Cui, Shoukun Xu, Jiangshuai Wang, Lin Shi, Haoping Peng, Fei Zhao
With the increase of conventional energy consumption around the world, the development of clean and efficient unconventional energy is in high demand.[1–4] As a new form of clean energy, shale oil has become a research highlight internationally, which features stable distribution, large thickness and wide distribution.[5] China is rich in continental shale oil resources, and the development and utilization of unconventional resources such as shale oil is an important to achieve China’s "energy independence". In the past decades, organic-rich shale has regained the attention of explorers and researchers. As an important field of unconventional oil and gas exploration, shale oil has huge resource potential.[6–7] However, in some areas, shale formation fractures and faults are developed, especially when the wellbore leakage phenomenon occurs after annulus-formation fluid displacement.[8–10] After the annulus is replaced with the formation fluid, the density and rheology of the drilling fluid in the wellbore are no longer constant, but change with the temperature.[11–13] Whether to describe the variation law of the temperature in the wellbore along the well depth under the replacement condition accurately is vital to the drilling project,[14] therefore, it is necessary to systematically analyze the characteristics and influence laws of the displacement phenomenon between the annulus and the formation fluid.
The impact of the North American shale gas technology on the US’ energy security: the case of natural gas
Published in International Journal of Sustainable Energy, 2022
Masoud Shirazi, Abdolrasoul Ghasemi, Jurica Šimurina
From the aspect of outcomes, the benefits of the shale gas technology for the economy are classified into explicit market impacts, e.g. raise in consumer surplus due to lower gas prices, increase in producer surplus and local as well as regional economic benefits, and implicit effects including air quality standards and climate change improvements as a result of emissions reductions2. Especially, the shale gas technology declines natural gas production cost by reducing the separation costs through potential economic and technical infrastructure, which leads to lower natural gas prices. Furthermore, the intermediate technology of shale gas revolution mitigates the short-term environmental concerns of the US’ economy since the price reduction of natural gas may decrease emissions (Acemoglu et al. 2019). Accordingly, the North-American shale gas technology is recognised as a potential affecting factor to analyse the short-term and long-term behavioural characteristics of the US’ energy environment.
CO2 sequestration with enhanced shale gas recovery
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Danqing Liu, Yilian Li, Seng Yang, Ramesh K. Agarwal
Shale gas resources are in abundance around the world, and the current global estimate of natural gas reserves in unconventional shale is approximately 716 trillion m3. In recent years, production from unconventional natural gas reservoirs has substantially expanded with the advent of horizontal drilling and high-volume hydraulic fracturing. The unconventional extraction of shale gas has already expanded from the U.S. to Canada, South Africa, Europe, China and Australia which have significant shale reservoirs. Despite the large resource potential and economic benefits, the rapid expansion of shale gas development has triggered severe environmental and human health concerns such as air pollution, greenhouse gas emissions, radiation, and groundwater and surface water contamination. Furthermore, in case of a single shale gas well, the gas rate decreases rapidly after a few years of production and the ultimate recovery is poorly constrained in the early stages of shale development. Consequently, the effective but environmental friendly enhanced shale gas recovery technology needs to be employed.