Acoustic logging response law in shales based on petrophysical model

Shale acoustic logging response law is complex due to the multiple minerals and pores,which limits the application of acoustic logging in shale reservoir parameter evaluation,therefore clarifying the shale acoustic logging response law is of great importance.Different petrophysical models are adopted for the equivalence of organic matter,clay,matrix minerals,and fractures,in Wufeng-Longmaxi shale formation in the Jiaoshiba area.Finally,the self-consistent approximation model is used to combine different components,and a shale petrophysical model with a complex pore structure is constructed.The model verification results show it has good predictability for shale.Based on the model,the effect of different mineral compositions and different types of pores are studied.The results show that:1)The effect of clay and organic matter is very complex,and the variation laws of layered clay(organic matter)and dispersed clay(organic matter)on the acoustic wave are consistent.2)Layered clay or organic matter leads to the formation anisotropy increase,which makes the acoustic time difference greater than that of containing dispersed clay(organic matter).3)The fracture is the main control factor of anisotropy,and the anisotropy of gas-bearing fracture is higher than that of water/oil fracture.

The feasibility of leadless pacemaker implantation in nonagenarians:case report and literature review

In the aging populations of China,there is an increasing prevalence of various types of bradycardias that require pacing therapy.In 1958,the first transvenous pacemaker(TVPM)was implanted at Karolinska Hospital in Sweden,which unveiled the era of cardiac pacing therapy.[1]A TVPM includes transvenous electrodes and a pulse gener-ator that is implanted subcutaneously.Despite its obvious benefits,the complication rate associated with TVPM could be as high as 10%.

Long-term outcomes of high-risk percutaneous coronary interventions under extracorporeal membrane oxygenation support:An observational study

BACKGROUND Venoarterial extracorporeal membrane oxygenation(VA-ECMO)offers hemodynamic support for patients undergoing high-risk percutaneous coronary interventions(PCIs).However,long-term outcomes associated with VA-ECMO have not previously been studied.AIM To explore long-term outcomes in high-risk cases undergoing PCI supported by VA-ECMO.METHODS In the present observational cohort study,61 patients who received VA-ECMOsupported high-risk PCI between April 2012 and January 2020 at the Sixth Medical Center of Chinese People’s Liberation Army General Hospital were enrolled.The endpoint characteristics such as all-cause mortality,repeated cardiovascular diseases,and cardiac death were examined.RESULTS Among 61 patients,three failed stent implantation due to chronic total occlusions with severely calcified lesions.One patient showed VA-ECMO intolerance because of high left ventricular afterload.PCI was successfully performed in 57 patients(93.4%).The in-hospital mortality was 23.0%,and the overall survival was 45.9%,with a median follow-up period of 38.6(8.6-62.1)mo.CONCLUSION VA-ECMO can be used as a support in patients undergoing high-risk PCI as it is associated with favorable long-term patient survival.