An innovative nitrogen injection assisted in-situ conversion process for oil shale recovery: Mechanism and reservoir simulation study

Pei, Shufeng; Wang, Yanyong; Zhang, Liang; Huang, Lijuan; Cui, Guodong; Zhang, Panfeng; Ren, Shaoran

doi:10.1016/j.petrol.2018.07.071

Cited by 57 publications

(38 citation statements)

References 13 publications

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“…The in situ convection heating pyrolysis technology of oil shale has a high heating efficiency and can provide the driving force for heat-carrying fluid and the pyrolysis of oil and gas migration (Tanaka et al 2011;Sun et al 2014;Kang 2008). These characteristics allow it to be a more suitable potential oil shale in situ pyrolysis technology compared to ground retorting and in situ conduction heating (Pei et al 2018). The schematic diagram of in situ convection heating pyrolysis technology is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Anisotropic Mechanical Properties of Oil Shales Under Real-Time High-Temperature Conditions

et al. 2021

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The anisotropic mechanical and acoustic emission characteristics of oil shale from room temperature to 600 °C were studied using a real-time high-temperature uniaxial rock testing machine independently developed by the Taiyuan University of Technology and an acoustic emission test system. The results indicate that the elastic modulus and compressive strength of the oil shale perpendicular to bedding direction first decrease and then increase with increasing temperature from room temperature to 600 °C and reach their minimum values at 400 °C, showing the characteristics of first softening and then hardening. The threshold temperature of oil shale mechanical parameters in the direction perpendicular to bedding direction is 400 °C. The strength of oil shale parallel to the bedding direction decreases sharply at 100 and 400 °C due to free water evaporation and kerogen pyrolysis, respectively. The threshold temperatures of oil shale mechanical parameters parallel to bedding direction are 100 and 400 °C. The micro-SEM and CT analyses conclude that the transformation of the mineral structure changes the mechanical parameters of oil shale perpendicular to bedding, and the evolution of the fracture structure dominates the change in the mechanical parameters of oil shale parallel to bedding. The results of this study can provide a theoretical data basis for elucidating the in situ pyrolysis of oil shales.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on the Anisotropic Mechanical Properties of Oil Shales Under Real-Time High-Temperature Conditions

et al. 2021

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“…The pore compression of oil shale is more uniform, and it is not easy to cause stress concentration, which leads to the pressure difference between the oil and gas occurrence space and the outside being less than the minimum fracturing pressure in the pores of the oil shale, as shown in Figure 9. Pei et al Obtained the same influence mechanism in the study of a new nitrogen injection in-situ transformation process mechanism and reservoir simulation of oil shale [24]. Therefore, the possibility is reduced that primary pores where oil and gas products are produced by pyrolysis of oil shale are ruptured, which leads to the oil and gas products produced by in-situ pyrolysis of oil shale escaping the primary pore where its storage is hindered.…”

Section: Effect Of Mining Flow Pressure On Productivitymentioning

confidence: 90%

Productivity Analysis of Fuyu Oil Shale In-Situ Pyrolysis by Injecting Hot Nitrogen

Zhao

Lü

et al. 2021

Energies

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In this paper, the effect of heat injection on productivity of Fuyu oil shale during in-situ pyrolysis was studied by using heat flow coupling analysis method. It is found that fluid conducts heat transmission to the oil shale stratum mainly along the fissure formed by hydraulic fracturing. With the increase of heating time, the oil shale on both sides of fissures were effectively pyrolyzed, and the porosity of the formation increases and the diffusion range of the nitrogen to the oil shale stratum is also improved. After 200 days, the oil shale around the fractures first reaches the pyrolysis temperature, and 700 days later, the average temperature of the oil shale stratum reaches 500 °C; therefore, the whole oil shale can be effectively pyrolyzed. Productivity analysis shows that the best exploitation temperature is 500 °C. When the gas injection rate is in the range of 1.0~11.0 m3/min, different degrees of heat loss will occur, and the output is also different. The pyrolysis time reaches 100~150 days, showing the peak value of daily production, which is between 0.5~3.2 m3/day. The pressure of displacement fluid affects oil shale product recovery in in-situ pyrolysis. High pressure helps to improve the displacement efficiency of oil and gas products and increase the productivity of oil shale in-situ pyrolysis. The best acting pressure is 9.5 MPa.

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“…Vigorous combustion was observed at the early stages near the heel of the injection well [22]. Pei et al studied the effect of nitrogen injection on the effectiveness of in-situ conversion process by numerical simulation [23]. Nesterov et al found that the activation energy of the light fraction in the oil is the most significant factor which affects the possibility of ignition through numerical simulation [24].…”

Section: Research Statusmentioning

confidence: 99%

Numerical Simulation Study of Heavy Oil Production by Using In-Situ Combustion

2019

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An in-situ combustion method is an effective method to enhance oil recovery with high economic recovery rate, low risk, fast promotion and application speed. Currently, in-situ combustion technique is regarded as the last feasible thermal recovery technology to replace steam injection in the exploitation of bitumen sands and heavy oil reservoirs. However, the oil-discharging mechanism during the in-situ combustion process is still not clearly understood. In this paper, the in-situ combustion process has been numerically simulated based on the Du 66 block. The effect of production parameters (huff and puff rounds, air injection speed, and air injection temperature) and geological parameters (bottom water thickness, stratigraphic layering, permeability ratio, and formation thickness) on the heavy oil recovery have been comprehensively analyzed. Results show that the flooding efficiency is positively correlated with the thickness of the bottom water, and negatively correlated with the formation heterogeneity. There exist optimum values for the oil layer thickness, huff and puff rounds, and air injection speed. And the effect of air injection temperature is not significant. The results of this paper can contribute to the understanding of mechanisms during in-situ combustion and the better production design for heavy oil reservoirs.

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An innovative nitrogen injection assisted in-situ conversion process for oil shale recovery: Mechanism and reservoir simulation study

Cited by 57 publications

References 13 publications

Experimental Study on the Anisotropic Mechanical Properties of Oil Shales Under Real-Time High-Temperature Conditions

Experimental Study on the Anisotropic Mechanical Properties of Oil Shales Under Real-Time High-Temperature Conditions

Productivity Analysis of Fuyu Oil Shale In-Situ Pyrolysis by Injecting Hot Nitrogen

Numerical Simulation Study of Heavy Oil Production by Using In-Situ Combustion

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