A numerical simulation study using the CMG-STAR Simulator was performed to compare the performance of the newly developed process (VWSAGD) utilizing vertical wells to enhance heavy oil recovery during steam assisted g...A numerical simulation study using the CMG-STAR Simulator was performed to compare the performance of the newly developed process (VWSAGD) utilizing vertical wells to enhance heavy oil recovery during steam assisted gravity drainage against the conventional steam assisted gravity drainage process which utilized horizontal wells (HWSAGD) under the same operating conditions. Two identical reservoir models were simulated for the two processes using 3-Dimensional, black heavy oil model (14° API). Each reservoir type consists of 49 × 49 × 20 grid blocks on a 5-acre model, which incorporated a typical heavy oil reservoir rock and fluid properties taken from the SPE case study, stspe001.dat (CMG 2015 release). A sensitivity analysis for both processes was performed for the grid density, soaking time, steam quality, bottom hole producing pressure, steam injection rate, reservoir thickness, reservoir area, and horizontal to vertical permeability anisotropy. More preferable reservoir conditions are those such as high horizontal to vertical permeability ratio, thick reservoir oil zones, as well as improved reservoir recovery for the VWSAGD process. Under unfavorable conditions such as thin reservoir oil zones, an improved reservoir recovery response was limited for the VWSAGD process and could be uneconomical in real field cases. Finally, the simulation results from this study include cumulative recoveries, Steam oil ratios, produced water-oil ratios, pressure and temperature distributions, and production rates. In addition, the results from this study have shown that the new VWSAGD process is more favorable than the conventional HWSAGD process.展开更多
BACKGROUND With the increasing use of extended-criteria donor organs,the interest around Ttubes in liver transplantation(LT)was restored whilst concerns regarding T-tuberelated complications persist.AIM To describe in...BACKGROUND With the increasing use of extended-criteria donor organs,the interest around Ttubes in liver transplantation(LT)was restored whilst concerns regarding T-tuberelated complications persist.AIM To describe insertion and removal protocols implemented at our institution to safely use pediatric rubber 5-French T-tubes and subsequent outcomes in a consecutive series of adult patients.METHODS Data of consecutive adult LT patients from brain-dead donors,treated from March 2017 to December 2019,were collected(i.e.,biliary complications,adverse events,treatment after T-Tube removal).Patients with upfront hepaticojejunostomy,endoscopically removed T-tubes,those who died or received retransplantation before T-tube removal were excluded.RESULTS Seventy-two patients were included in this study;T-tubes were removed 158 d(median;IQR 128-206 d)after LT.In four(5.6%)patients accidental T-tube removal occurred requiring monitoring only;in 68(94.4%)patients Nelaton drain insertion was performed according to our protocol,resulting in 18(25%)patients with a biliary output,subsequently removed after 2 d(median;IQR 1-4 d).Three(4%)patients required endoscopic retrograde cholangiopancreatography(ERCP)due to persistent Nelaton drain output.Three(4%)patients developed suspected biliary peritonitis,requiring ERCP with sphincterotomy and nasobiliary drain insertion(only one revealing contrast extravasation);no patient required percutaneous drainage or emergency surgery.CONCLUSION The use of pediatric rubber 5-French T-tubes in LT proved safe in our series after insertion and removal procedure refinements.展开更多
Background and aims:Laparoscopic common bile duct exploration(LCBDE)is considered a safe and effective method for the removal of bile duct stones.However,the choice of primary duct closure(PDC)or T-tube drainage(TTD)t...Background and aims:Laparoscopic common bile duct exploration(LCBDE)is considered a safe and effective method for the removal of bile duct stones.However,the choice of primary duct closure(PDC)or T-tube drainage(TTD)technique after LCBDE is still controversial.This study aimed to compare the safety and effectiveness of PDC and TTD after LCBDE.Methods:Studies published before May 1,2021 in Pub Med,Web of Science,and Cochrane Library databases were searched to screen out randomized controlled trials(RCTs)and cohort studies to compare PDC with TTD.Meta-analyses of fixed effect and random effect models were performed using Rev Man 5.3.Results:A total of 1865 patients were enrolled in six RCTs and ten cohort studies.Regarding RCTs,the PDC group was significantly better than the TTD group in terms of operation time,total postoperative complications,postoperative hospital stay,and hospitalization expenses(all P<0.05).Based on cohort studies of the subgroup,the PDC group had shorter operation time,shorter postoperative hospital stay,less intraoperative blood loss,and limited total postoperative complications.Statistically,there were no significant differences in bile leakage,retained stones,stone recurrence,bile duct stricture,postoperative pancreatitis,other complications,or postoperative exhaust time between the TTD and PDC groups.Conclusions:Based on the available evidence,compared with TTD,PDC is safe and effective,and can be used as the first choice after transductal LCBDE in patients with choledocholithiasis.展开更多
文摘A numerical simulation study using the CMG-STAR Simulator was performed to compare the performance of the newly developed process (VWSAGD) utilizing vertical wells to enhance heavy oil recovery during steam assisted gravity drainage against the conventional steam assisted gravity drainage process which utilized horizontal wells (HWSAGD) under the same operating conditions. Two identical reservoir models were simulated for the two processes using 3-Dimensional, black heavy oil model (14° API). Each reservoir type consists of 49 × 49 × 20 grid blocks on a 5-acre model, which incorporated a typical heavy oil reservoir rock and fluid properties taken from the SPE case study, stspe001.dat (CMG 2015 release). A sensitivity analysis for both processes was performed for the grid density, soaking time, steam quality, bottom hole producing pressure, steam injection rate, reservoir thickness, reservoir area, and horizontal to vertical permeability anisotropy. More preferable reservoir conditions are those such as high horizontal to vertical permeability ratio, thick reservoir oil zones, as well as improved reservoir recovery for the VWSAGD process. Under unfavorable conditions such as thin reservoir oil zones, an improved reservoir recovery response was limited for the VWSAGD process and could be uneconomical in real field cases. Finally, the simulation results from this study include cumulative recoveries, Steam oil ratios, produced water-oil ratios, pressure and temperature distributions, and production rates. In addition, the results from this study have shown that the new VWSAGD process is more favorable than the conventional HWSAGD process.
文摘BACKGROUND With the increasing use of extended-criteria donor organs,the interest around Ttubes in liver transplantation(LT)was restored whilst concerns regarding T-tuberelated complications persist.AIM To describe insertion and removal protocols implemented at our institution to safely use pediatric rubber 5-French T-tubes and subsequent outcomes in a consecutive series of adult patients.METHODS Data of consecutive adult LT patients from brain-dead donors,treated from March 2017 to December 2019,were collected(i.e.,biliary complications,adverse events,treatment after T-Tube removal).Patients with upfront hepaticojejunostomy,endoscopically removed T-tubes,those who died or received retransplantation before T-tube removal were excluded.RESULTS Seventy-two patients were included in this study;T-tubes were removed 158 d(median;IQR 128-206 d)after LT.In four(5.6%)patients accidental T-tube removal occurred requiring monitoring only;in 68(94.4%)patients Nelaton drain insertion was performed according to our protocol,resulting in 18(25%)patients with a biliary output,subsequently removed after 2 d(median;IQR 1-4 d).Three(4%)patients required endoscopic retrograde cholangiopancreatography(ERCP)due to persistent Nelaton drain output.Three(4%)patients developed suspected biliary peritonitis,requiring ERCP with sphincterotomy and nasobiliary drain insertion(only one revealing contrast extravasation);no patient required percutaneous drainage or emergency surgery.CONCLUSION The use of pediatric rubber 5-French T-tubes in LT proved safe in our series after insertion and removal procedure refinements.
基金supported by the National Natural Science Foundation of China(Nos.81972262,81972255,81772597,81801999,and 81702904)the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515010117 and2018A030313645)+4 种基金the Fundamental Research Funds for the Central Universities(No.18ykpy22)the Key Laboratory of Malignant Tumor Molecular Mechanism and Translational Medicine of Guangzhou Bureau of Science and Information Technology(No.[2013]163)the Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institutes(No.KLB09001)the Guangdong Science and Technology Department(Nos.2015B050501004and 2017B030314026)the Shangrao Science and Technology Department(No.2020D001),China。
文摘Background and aims:Laparoscopic common bile duct exploration(LCBDE)is considered a safe and effective method for the removal of bile duct stones.However,the choice of primary duct closure(PDC)or T-tube drainage(TTD)technique after LCBDE is still controversial.This study aimed to compare the safety and effectiveness of PDC and TTD after LCBDE.Methods:Studies published before May 1,2021 in Pub Med,Web of Science,and Cochrane Library databases were searched to screen out randomized controlled trials(RCTs)and cohort studies to compare PDC with TTD.Meta-analyses of fixed effect and random effect models were performed using Rev Man 5.3.Results:A total of 1865 patients were enrolled in six RCTs and ten cohort studies.Regarding RCTs,the PDC group was significantly better than the TTD group in terms of operation time,total postoperative complications,postoperative hospital stay,and hospitalization expenses(all P<0.05).Based on cohort studies of the subgroup,the PDC group had shorter operation time,shorter postoperative hospital stay,less intraoperative blood loss,and limited total postoperative complications.Statistically,there were no significant differences in bile leakage,retained stones,stone recurrence,bile duct stricture,postoperative pancreatitis,other complications,or postoperative exhaust time between the TTD and PDC groups.Conclusions:Based on the available evidence,compared with TTD,PDC is safe and effective,and can be used as the first choice after transductal LCBDE in patients with choledocholithiasis.
