Horizontal well screen completion process has its own advantages, but there are also some problems, in which the screen blockage seriously affects its efficacy. However, due to various factors (such as heavy components in crude oil plugging the sand filter), the implementation of conventional pickling and sand washing operations is not ideal. In response to this problem, this paper proposes a new unblocking technology - segmentation unblocking technology for horizontal well screen. Firstly, on the basis of studying principle of the technology, optimization of water jet method and hydraulic sanding nozzle, nitrogen foam water jet experiment and water jet construction displacement experiment are carried out for horizontal well screen, which laying the foundation for application of segmentation unblocking technology. Further, horizontal well screen segmentation unblocking experiment and oilfield application are carried out. Optimization results of water jet method show that, For large displacement construction with still wellhead, whole section construction selects type of inlet liquid through annulus between oil pipe and casing pipe and outlet liquid through oil pipe. For small displacement construction with frequent dynamic wellhead, segmentation construction selects type of inlet liquid through oil pipe and outlet liquid through annulus between oil pipe and casing pipe. Optimization results of hydraulic sanding nozzle show that Streamlined nozzle is better than nozzle with iso variable. Experiment results of horizontal well screen segmentation unblocking show that, segmentation unblocking technology can effectively improve productivity of horizontal well and oilfield application achieved good results. Five wells were shut-in, periodic shut-in or low production before segmentation unblocking. After segmentation unblocking, daily oil increment can reach 23.57 t, and interval cumulative oil increment can reach 4756 t.

BackgroundThe prognosis of severe COVID-19 patients is poor. Traditional Chinese Medicine had an advantage in keeping microenvironmental balance in treating SARS and COVID-19.MethodsThis prospective cohort study compared the efficacy and safety of integrative Chinese-Western medicine (ICWM) treatments with Western medicine (WM) treatments in severe or critically ill patients. The outcomes included: mortality, hospital stay in ICU, days with ventilator-assisted ventilation, etc.ResultsA total of 72 confirmed COVID-19 patients in ICU were included. The median age of patients was 66 years (IQR: 53-77.5), and there were 32 female patients (44.4%). There were no significant differences in laboratory tests and complications after treatments between groups. A total of 36 (50%) patients died during hospitalization, and the mortality in the ICWM group (28.6%) was significantly lower than that of the WM group (63.6%, adjusted P=0.011). And the time of assisted ventilation was shorter in the ICWM group (adjusted P=0.341). However, the median hospital stay was significantly longer in the ICWM group (18 vs. 14 days, adjusted P＜0.05).ConclusionsICWM treatments could significantly reduce mortality for severe or critically ill patients with COVID-19, and it was safe and cost-effective to add Chinese medicine.

Background The prognosis of severe COVID-19 patients is poor. There are currently no definitely effective vaccines or antivirus drugs for COVID-19.Methods This prospective cohort study compared the efficacy and safety of integrative Chinese-Western medicine (ICWM) treatments with Western medicine (WM) treatments in severe or critically ill patients. The outcomes included: mortality, hospital stay in ICU, days with ventilator-assisted ventilation, etc.Results A total of 36 confirmed COVID-19 patients in ICU were included. The median age of patients was 66 years (IQR: 53-77.5), and there were 16 female patients (44.4%). There were no significant differences in laboratory tests and complications after treatments between groups. A total of 18 (50%) patients died during hospitalization, and the mortality in the ICWM group (28.6%) was significantly lower than that of the WM group (63.6%, adjusted P = 0.031). And the time of assisted ventilation was shorter in the ICWM group (adjusted P = 0.67). However, the median hospital stay was significantly longer in the ICWM group (18 vs. 14 days, adjusted P༜0.05).Conclusions ICWM treatments could significantly reduce the mortality and improve the clinical symptoms for severe or critically ill patients with COVID-19, and it was safe and cost-effective to add Chinese medicine.

In order to solve the problems about rapid increasement rate of water cut and large production decline in bottom water heavy oil reservoir due to active bottom water and high crude oil viscosity, the research on CO2 huff-and-puff technology is carried out. The results showed that the mechanism of CO2 huff-and-puff was mainly to reduce the viscosity of heavy crude oil, carbonate reacted with bottom water and formed interlayer to achieve viscosity reduction and precipitation. The comprehensive water cut was decreased by 35%, and the average oil production of a single well was increased by 3∼4 times. Therefore, CO2 huff-and-puff technology was one of technologies about bottom water control and oil production stabilization, and it is of great significance to enhance oil production in heavy oil bottom water reservoirs.