Utilization mechanism of foam flooding and distribution situation of residual oil in fractured-vuggy carbonate reservoirs

The development of fractured-vuggy carbonate reservoirs is extremely difficult because of the complex fractured-vuggy structure and strong heterogeneity.Foam flooding is a potential enhanced oil recovery(EOR)technology in fractured-vuggy carbonate reservoirs.Based on the similarity criterion,three types of 2D visual physical models of the fractured-vuggy structure were made by laser ablation technique,and a 3D visual physical model of the fractured-vuggy reservoir was made by 3D printing technology.Then the physical analog experiments of foam flooding were carried out in these models.The experimental results show that foam can effectively improve the mobility ratio,control the flow velocity of the fluid in different directions,and sweep complex fracture networks.The effect of foam flooding in fractures can be improved by increasing foam strength and enhancing foam stability.The effect of foam flooding in vugs can be improved by reducing the density of the foam and the interfacial tension between foam and oil.Three types of microscopic residual oil and three types of macroscopic residual oil can be displaced by foam flooding.This study verifies the EOR of foam flooding in the fractured-vuggy reservoir and provides theoretical support for the application of foam flooding in fractured-vuggy reservoirs.

CircRNA_0084927 promotes colorectal cancer progression by regulating miRNA-20b-3p/glutathione S-transferase mu 5 axis

BACKGROUND Colorectal cancer(CRC)is the third most common cancer and the second most common cause of cancer-related death worldwide.The 5-year survival rate of patients with early-stage CRC could reach 90%,but it is very low in patients with advanced-stage CRC.Recent studies have shown that circular RNAs play important roles in regulating the migration and invasion of CRC cells.AIM To elucidate the role of circRNA_0084927(circ_0084927)in the migration and invasion of CRC cells and its underlying mechanism.METHODS Clinical tissue samples and cells were collected,and the expression of circ_0084927 was detected by quantitative polymerase chain reaction(qPCR).The diagnostic performance of circ_0084927 was assessed by receiver operating characteristic curve analysis.The role of circ_0084927 in CRC cell proliferation,migration,and invasion was determined using cell counting kit-8 assay,wound healing assay,and transwell assay,respectively.The regulatory relationship among circ_0084927,miRNA-20b-3p(miR-20b-3p),and glutathione S-transferase mu 5(GSTM5)was identified using databases,luciferase reporter assay,qPCR,and Western blot analysis.AKT-mTOR signaling was also verified after circ_0084927 knockdown or miR-20b-3p mimic treatment.RESULTS The expression of circ_0084927 was significantly increased in CRC tissues and cells,and it was higher in advanced-stage CRC compared with early-stage CRC.The area under the curve(AUC)of circ_0084927 was 0.806[95%confidence interval(CI):0.683-0.896].In addition,the AUC was 0.874(95%CI:0.738-0.956)in patients with advanced-stage CRC and 0.713(95%CI:0.555-0.840)in those with early-stage CRC.Knockdown of circ_0084927 inhibited the migration and invasion of HCT116 cells.Moreover,circ_0084927 was found to act as a sponge of miR-20b-3p.MiR-20b-3p activation reduced the circ_0084927 level,whereas miR-20b-3p inhibition increased the circ_0084927 level.But the effect was not found after circ_0084927 mutation.In addition,miR-20b-3p expression in CRC patients was also reduced and negatively correlated with circ_0084927 expression.The function of circ_0084927 in HCT116 cells with circ_0084927 knockdown was rescued by miR-20b-3p.Moreover,GSTM5 expression was significantly decreased after overexpressing miR-20b-3p or inhibiting circ_0084927,but its expression was rescued when circ_0084927 and miR-20b-3p were both inhibited.Finally,AKTmTOR signaling was markedly regulated by circ_0084927 and miR-20b-3p.CONCLUSION The expression of circ_0084927 is significantly increased in CRC and higher in advanced-stage CRC than in early-stage CRC.Moreover,circ_0084927 potentially regulates CRC cell migration and invasion via the miR-20b-3p/GSTM5/AKT/mTOR pathway.