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What instead of oil?
Published in Rauli Partanen, Harri Paloheimo, Heikki Waris, The World After Cheap Oil, 2014
Rauli Partanen, Harri Paloheimo, Heikki Waris
Unconventional oil includes oil sands, shale oil, and kerogen oil (oil shale). These are hydrocarbons that can be refined or upgraded to match conventional oil with reasonably little effort. Their production is very different from conventional oil production. For example they are often mined, not pumped.
Performance of supercritical nitrogen in a double flow space well for uniform injection of unconventional reservoirs
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Jiaxi Gao, Yuedong Yao, He Bao, Wenling Gao
With the development of economy (Fengrui et al. 2017), the demand for oil is further increasing (Huang et al. 2020). However, at present, the water cut of conventional oilfield is high, and the productivity is decreasing (Zhiwang et al. 2018). Therefore, the exploration and development focus of international oil companies is gradually shifting to unconventional oil and gas resources (DiGiulio, Shonkoff, and Jackson 2018). Unconventional oil and gas resources generally include shale gas (Gao et al. 2021), coalbed methane (Labussière 2021), tight gas (Ding et al. 2021), shale oil (Yang et al. 2021), oil shale (Wang et al. 2021), tight oil (Wachtmeister and Mikael 2020), heavy oil (Zhang et al. 2021), and low permeability oil and gas fields etc. (Chen et al. 2020). For the development of these unconventional oil and gas resources (Zhang et al. 2020), nitrogen injection is a common way to enhance oil recovery (Mogensen and Siqing 2020). The parameters of nitrogen injection have a significant effect on the effect of enhanced oil recovery (Kang et al. 2019). Therefore, many scholars have conducted research on wellbore pipe flow in order to provide guidance for the optimization of oilfield injection and production parameters (Xiaojiang et al. 2017).
Saturates and aromatics characterization in heavy crude oil upgrading using Ni–Co/γ-Al2O3 catalysts
Published in Petroleum Science and Technology, 2020
Onoriode P. Avbenake, Rashid S. Al-Hajri, Baba Y. Jibril
Among the eight types of unconventional oil and gas resources available—heavy crude, oil sand, oil shale, gas and syncrude from coal, tight gas, coalbed methane, gas hydrates, and biofuels; heavy crude oil is most promising because of its abundance (Shah et al. 2011) and extensive study (Greff and Babadagli 2011; Galukhin et al. 2015). They are characterized with low API gravity and higher content heavy molecular weight hydrocarbons resulting in high viscosity, which de-activates catalysts during refining and impedes its free flow during production respectively.
Inversing fracture parameters using early-time production data for fractured wells
Published in Inverse Problems in Science and Engineering, 2020
Zixi Guo, Yiyu Chen, Xiang Zhou, Fanhua Zeng
Analysis models serve as the basis of well test analyses for fractured wells. Previously established models for wells with symmetrically vertical fractures in conventional reservoirs mainly include the bilinear flow model [1,2], the trilinear flow model [3], the oval flow model [4], and the combined model [5,6]. Some studies have developed analysis models for asymmetrical fractures [7,8], inclined fractures [9], fractal reservoirs [10,11], and anisotropic reservoirs [12]. In recent years, the combination of horizontal wells and hydraulic fracturing has made it possible to exploit unconventional oil and gas reservoirs. Therefore, shale, tight oil, and gas reservoirs gradually have become important resources. Examples of unconventional reservoir models include the radial/linear dual-porosity model [13,14], the radial/linear triple-porosity model [15–17], and the multilinear flow model [18–21]. To evaluate and optimize fracturing design and its effects on well performance, Yuan et al. [22] developed a multilinear flow solution to characterize the effects of nonuniform fracture intensities on well production in tight gas reservoirs, providing an efficient analytical approach to analyse multiple flow regimes and predicate ultimate recovery efficiency. Yuan et al. [23] proposed a novel concept of dynamic drainage volume (DDV) to describe accurately the characteristics of long-term transient flow in shale plays and applied it to improve the analysis of production data for unconventional reservoirs. Yuan et al. [24] proposed a novel workflow and iterative algorithm for production data analysis by integrating history evaluation, production predication, and optimization of well fracturing and spacing in Niobrara shale plays. The main problem with these models is that usually they are established in constant-rate circumstances to describe the transient-pressure behaviour, but in practice the flow is variable. In order to solve this problem, some previous methods have extended constant-flow-rate models to variable-flow-rate models, such as decline curve analysis (DCA), rate-time analysis (RTA), numerical model history-matching (HM) [25,26], and the superposition model, which is the most common.