| 1. |
- Lu, Zhaohui, et al.
(författare)
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Microseismic Monitoring of Hydraulic Fracture Propagation and Seismic Risks in Shale Reservoir with a Steep Dip Angle
- 2022
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Ingår i: Natural Resources Research. - : Springer Nature. - 1520-7439 .- 1573-8981. ; 31:5, s. 2973-2993
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Tidskriftsartikel (refereegranskat)abstract
- Hydraulic fracturing is an essential technique to increase reservoir permeability and enhance the production of shale gas. When the dip angle is steep and geological condition is complex, hydraulic fractures may behave complexly, and research on this topic is critical for the shale gas industry. This paper reports a case study of hydraulic fracturing in a shale reservoir with a steep dip angle. We monitored pump data, including the injection rate and fluid pressure. Microseismic monitoring was also used to record the seismic events and monitor the hydraulic fracture propagation. Our results validated that microseismic monitoring is a feasible technique to monitor the hydraulic fracture propagation in shale reservoirs with steep dip angles. Moreover, the variation in depth of shale reservoir induces significant alternation of local in situ stress states, in which cases the fracture propagation pathway is more complex, and where microseismic monitoring is necessary to acquire the hydraulic fracture distribution. Besides, all sound sources, including quarries and rivers, should be eliminated during microseismic station arrangement to improve accuracy of microseismic signals. Moreover, the relationship between the maximum magnitude of seismic event and fluid injection volume was validated further in this study. Finally, unexpected faults and aquifers may affect hydraulic fracture propagation due to the steep dip angle of the target shale reservoir. Thus, a comprehensive geological survey is essential for better hydraulic fracturing design. Our results provide first-hand in situ hydraulic fracturing data and provide important implications for shale gas development, especially for those shale reservoirs with steep dip angles.
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| 2. |
- Ouyang, Liming, 1974, et al.
(författare)
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Integrated analysis of the yeast NADPH-regulator Stb5 reveals distinct differences in NADPH requirements and regulation in different states of yeast metabolism
- 2018
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Ingår i: FEMS Yeast Research. - : Oxford University Press (OUP). - 1567-1356 .- 1567-1364. ; 18:8
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Tidskriftsartikel (refereegranskat)abstract
- The Saccharomyces cerevisiae transcription factor (TF) Stb5 is known to be involved in regulating NADPH generation. We explored its role by combining DNA binding studies with transcriptome analysis at four environmental conditions that were selected to cover a range of different metabolic states. Using ChIP-exo, DNA binding targets of Stb5 were found to confirm many previously proposed binding targets, in particular genes encoding enzymes involved in NADPH generation and the pentose-phosphate (PP) pathway. Transcriptome analysis of an STB5 deletion strain revealed transcriptional changes in direct regulation targets of Stb5, including several PP pathway genes as well as additional novel regulatory targets, but interestingly not including the proposed PP pathway flux controlling enzyme Zwf1. Consistently, NADPH levels were found to decrease significantly with STB5 deletion in cultures with aerobic, glucose metabolism. We also found reduced growth for the STB5 deletion strain in similar conditions as those with reduced NADPH levels, supporting a role for Stb5 in NADPH generation through the PP pathway. We finally explored the flux distribution by genome scale modelling simulations and found a decreased flux in both NADPH generating as well as consuming reactions in the STB5 deletion strain.
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