As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has ris...As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios: (1) re-fracturing versus no re- fracturing, (2) combination of re-fracturing and drilling new wells, and (3) time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.展开更多
We think we should use basic return rate of industry to measure the opportunity cost of capital and use the rule of Maximum NPV (Net Present Value) to modify the wrong solution in the book.
Objective To investigate the characteristic of heart rate variability(HRV)changes in patients with posteriorcirculation cerebral infarction and its value in prognosis prediction.Methods Fifty-four cases continuously d...Objective To investigate the characteristic of heart rate variability(HRV)changes in patients with posteriorcirculation cerebral infarction and its value in prognosis prediction.Methods Fifty-four cases continuously diagnosed with acute posterior circulation cerebral infarction from March 2015 to November 2015 in the Department展开更多
Purpose. This study is to investigate the influence of acupuncture at acupoints Neiguan (PC 6) and Ximen (PC 4) on the stroke volume and the flow rate of peak value of left ventricle ejection in the patients with ...Purpose. This study is to investigate the influence of acupuncture at acupoints Neiguan (PC 6) and Ximen (PC 4) on the stroke volume and the flow rate of peak value of left ventricle ejection in the patients with coronary heart disease. Methods. 60 cases of coronary heart disease were divided into acupoint Neiguan (PC 6) group and acupoint Ximen (PC 4) group, and the stroke volume and the flow rate of peak value of left ventricle ejection were detected 3 min after manipulating needles and 20 rain after retaining needles respectively, then were compared with those before acupuncture. Results. 3 min after manipulating needles, the stroke volume and the flow rate of peak value of left ventricle ejection were enhanced in 46 cases, and 20 min after retaining needles, both the stroke volume andthe flow rate of peak value of left ventricle ejection were all enhanced in 34 cases. Conclusion. Puncturing acupoints Neiguan (PC 6) and Ximen (PC 4) could enhance the contractility of left ventricle wall, increase the stroke volume of the heart and improve the myocardial ischemia in the patients with coronary heart disease.展开更多
文摘As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios: (1) re-fracturing versus no re- fracturing, (2) combination of re-fracturing and drilling new wells, and (3) time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.
文摘We think we should use basic return rate of industry to measure the opportunity cost of capital and use the rule of Maximum NPV (Net Present Value) to modify the wrong solution in the book.
文摘Objective To investigate the characteristic of heart rate variability(HRV)changes in patients with posteriorcirculation cerebral infarction and its value in prognosis prediction.Methods Fifty-four cases continuously diagnosed with acute posterior circulation cerebral infarction from March 2015 to November 2015 in the Department
文摘Purpose. This study is to investigate the influence of acupuncture at acupoints Neiguan (PC 6) and Ximen (PC 4) on the stroke volume and the flow rate of peak value of left ventricle ejection in the patients with coronary heart disease. Methods. 60 cases of coronary heart disease were divided into acupoint Neiguan (PC 6) group and acupoint Ximen (PC 4) group, and the stroke volume and the flow rate of peak value of left ventricle ejection were detected 3 min after manipulating needles and 20 rain after retaining needles respectively, then were compared with those before acupuncture. Results. 3 min after manipulating needles, the stroke volume and the flow rate of peak value of left ventricle ejection were enhanced in 46 cases, and 20 min after retaining needles, both the stroke volume andthe flow rate of peak value of left ventricle ejection were all enhanced in 34 cases. Conclusion. Puncturing acupoints Neiguan (PC 6) and Ximen (PC 4) could enhance the contractility of left ventricle wall, increase the stroke volume of the heart and improve the myocardial ischemia in the patients with coronary heart disease.