Hydrocarbon gas huff-n-puff optimization of multiple horizontal wells with complex fracture networks in the M unconventional reservoir

The oil production of the multi-fractured horizontal wells(MFHWs) declines quickly in unconventional oil reservoirs due to the fast depletion of natural energy. Gas injection has been acknowledged as an effective method to improve oil recovery factor from unconventional oil reservoirs. Hydrocarbon gas huff-n-puff becomes preferable when the CO_(2) source is limited. However, the impact of complex fracture networks and well interference on the EOR performance of multiple MFHWs is still unclear. The optimal gas huff-n-puff parameters are significant for enhancing oil recovery. This work aims to optimize the hydrocarbon gas injection and production parameters for multiple MFHWs with complex fracture networks in unconventional oil reservoirs. Firstly, the numerical model based on unstructured grids is developed to characterize the complex fracture networks and capture the dynamic fracture features.Secondly, the PVT phase behavior simulation was carried out to provide the fluid model for numerical simulation. Thirdly, the optimal parameters for hydrocarbon gas huff-n-puff were obtained. Finally, the dominant factors of hydrocarbon gas huff-n-puff under complex fracture networks are obtained by fuzzy mathematical method. Results reveal that the current pressure of hydrocarbon gas injection can achieve miscible displacement. The optimal injection and production parameters are obtained by single-factor analysis to analyze the effect of individual parameter. Gas injection time is the dominant factor of hydrocarbon gas huff-n-puff in unconventional oil reservoirs with complex fracture networks. This work can offer engineers guidance for hydrocarbon gas huff-n-puff of multiple MFHWs considering the complex fracture networks.

Hepatitis B virus and hepatocellular carcinoma at the miRNA level

AIM: To study Hepatitis B virus (HBV) infection and its association with hepatocellular carcinoma (HCC) at the miRNA level.METHODS: Three cellular models were used to investigate miRNA expression changes during HBV infection: human HepG2 hepatoblastoma cell line as a model without HBV infection;HepG2 cell line transfected with a 1.3-fold full-length HBV genome as an acute infection model;and HepG2.2.15 cell line,which is derived from HepG2 and stably transfected with a complete HBV genome,as a chronic infection model.The miRNA levels were examined using microarray technology.To explore the relationship between HBV infection and HCC genesis at the miRNA level,we downloaded from national center for biotechnology information Gene Expression Omnibus an miRNA expression dataset derived from HCC patients,most of whom are HBV carriers.We compared the miRNA expression alterations during HBV infection with those in HCC patients,by analyzing miRNA expression change profiles statistically.RESULTS: Seventy-seven and 48 miRNAs were differentially expressed during acute and chronic HBV infection,respectively.Among these miRNAs,25 were in common,the intersection of which was significant under the hypergeometric test (P = 1.3 × 10-11).Fourteen miRNAs were observed to change coherently in the acute and chronic infections,with one upregulated and 13 downregulated.Eleven showed inverse changes during the two phases of infection;downregulated in the acute infection and upregulated in the chronic infection.The results imply that common and specific mechanisms exist at the miRNA level during acute and chronic HBV infection.Besides,comparative analysis of the miRNA expression changes during HBV infection with those in HCC indicates that,although miRNA expression changes during HBV infection are distinct from those in HCC patients (P < 2.2 × 10-16),they exhibited significant correlations (P = 0.0229 for acute infection;P = 0.0084 for chronic infection).Perturbation of miRNA expression during chronic HBV infection was closer to that in HCC patients than that during acute HBV infection.This observation implies the contribution of miRNAs to HCC genesis from HBV infection.According to their patterns of differential expression in acute and chronic HBV infection,as well as in HCC,miRNAs of potential research interest could be identified,such as miR-18a/miR-18b,miR-106a,miR-221 and miR-101.For instance,the gradient expression alteration of miR-221 in the above three phases,which is downregulated in acute HBV infection,normally expressed in chronic HBV infection,and upregulated in HCC,indicates that it may be a key effector for progression of the disease.CONCLUSION: Our analysis provides insights into HBV infection and related HCC in relation to miRNAs,and reveals some candidate miRNAs for future studies.

The clinical and immunological features of pediatric COVID-19 patients in China

In December 2019,the corona virus disease 2019(COVID-19)caused by novel coronavirus(SARS-CoV-2)emerged in Wuhan,China and rapidly spread worldwide.Few information on clinical features and immunological profile of COVID-19 in paediatrics.The clinical features and treatment outcomes of twelve paediatric patients confirmed as COVID-19 were analyzed.The immunological features of children patients was investigated and compared with twenty adult patients.The median age was 14.5-years(range from 0.64 to 17),and six of the patients were male.The average incubation period was 8 days.Clinically,cough(9/12,75%)and fever(7/12,58.3%)were the most common symptoms.Four patients(33.3%)had diarrhea during the disease.As to the immune profile,children had higher amount of total T cell,CD8t T cell and B cell but lower CRP levels than adults(P<0.05).Ground-glass opacity(GGO)and local patchy shadowing were the typical radiological findings on chest CT scan.All patients received antiviral and symptomatic treatment and the symptom relieved in 3e4 days after admitted to hospital.The paediatric patients showed mild symptom but with longer incubation period.Children infected with SARS-CoV-2 had different immune profile with higher T cell amount and low inflammatory factors level,which might ascribed to the mild clinical symptom.We advise that nucleic acid test or examination of serum IgM/IgG antibodies against SARS-CoV-2 should be taken for children with exposure history regardless of clinical symptom.