As the exploration and development of Tuha Oilfield gradually advances toward deeper and more complex areas，the well site deployment is approaching environmentally sensitive farmland and forest. In order to ensure the safe drilling of deep wells，higher technical requirements are proposed on environment protection，high temperature resistance and handling capacity of downhole complex issues and anomalies of drilling fluids. Considering factors such as wellbore stability，wellbore cleanup，and reduction of friction and resistance，researches were conducted in terms of the drilling fluid performance of inhibition，plugging，lubrication and environment protection. Through the laboratory experiments to optimize the desulfonation degradable high temperature resistant treatment agent and system composition，a high temperature environmentally friendly drilling fluid system was derived from the composite salt drilling fluid formula. As shown in laboratory testing，the drilling fluid has stable performance at 160 °C，with the EC₅₀ of 5.1×10⁴，and is non-toxic with the heavy metal content complying with the national ecological environment discharge criteria. The HTHP fluid loss is less than 10 mL，the mud cake drag coefficient is 0.043 7-0.052 4，the yield point is greater than 12 Pa，and the shale rolling recovery rate is 95.36%. The high temperature environmentally friendly drilling fluid system has been successfully applied in Well Jixin-6. The drilling of the whole well is smooth with no complex issue，creating a new record of the deepest vertical depth of the Jixin-1 Block and sufficiently proving that the drilling fluid system has good performances of inhibition，plugging，cutting-carrying and lubrication.

Due to the extremely rich oil and gas resources in deep-sea area, the deep-sea oil and gas exploration at home and abroad has been heated up in recent years. The actual drilling in northern basins of South China Sea proves that the oil and gas resources are abundant and the exploration prospect is bright. As an operator, CNOOC has completed a total number of 8 deepwater wells with the depth of 1500 m in northern basins of South China Sea, forming a complete set of key drilling and completion technologies, such as shallow disaster prevention and control, well structure design and optimization, surface conduit injection and running, formation pressure monitoring while drilling, narrow window safe operation, hydrate prevention and control, drilling and completion fluid and cementing. Mastering this set of technologies is important to promote the sustainable development of China's offshore oil industry. It is of great significance to increase oil and gas production and ensure energy security. Taking the first deepwater well completed by CNOOC as an operator in Lingshui Block as an example, this paper introduces the key technologies and application results of deepwater drilling and completion in this area. 

At present，there are 3 types of oil production well sites in Xinjiang Oilfield，which are platform well，single well and cluster well sites. Pumping units and rodless pumps are main energy-consuming equipment，and electric heaters also consume some power. It has become the current trend to replace traditional energy sources with solar energy，because it is clean，harmless，and basically con- sumes no energy. Nevertheless，solar energy also has the disadvantages of poor continuity and stability，low energy density，high cost， large footprint and the necessity for outdoor installation. A distributed solar photovoltaic power generation test and modification was conducted on the oil production platform XY6 in Jimsar of Xinjiang Oilfield. The designed installed capacity is 8 kW. The in-situ gen- erated power is supplied to the power-consuming equipment located at the well site for self use，with the surplus power connected to the grid. In case of power shortage，power will be supplied from the grid. The layout of photovoltaic modules was decided after the optimum dip angle was calculated by designing the modules in series and parallel. In addition，an analysis was conducted by comparing with the data simulated by Pvsyst 7.2 to provide a detailed reference for the overall photovoltaic layout of the platform. By the end of the first quarter of 2022，about 3，000 kW·h power had been generated，and about 20，000 tons of carbon dioxide emissions had been reduced.