On December 7, at the artificial island of Nanbu 2 in Jidong Oilfield of PetroChina, with the valves of Nanbu 12-86 well and gas reservoir Ping1 wellhead slowly opened, Nanbu 1-29 gas storage started gas extraction, marking the first offshore gas storage in China officially entered the first round of gas extraction.
In 2021, Jidong Oilfield launched the pilot test of Nanbu 1-29 and Baogu 2 gas storage reservoirs. Nanbu 1-29 gas storage reservoir is the first offshore gas storage reservoir in China, and also the first reservoir storage reservoir in China, located in Nanbu 2 artificial island of Jidong Oilfield. As the first offshore gas storage reservoir converted from oil reservoir in China, the reservoir follows the principle of “fewer wells and higher efficiency”.
In order to enhance the expansion speed of the first offshore reservoir, Jidong Oilfield has conducted in-depth geological research and analysis, with the goal of improving gas drive discharge and gas injection efficiency, carried out dynamic tracking and evaluation, optimization of injection and extraction parameters and high-pressure nitrogen-assisted depressurization and injection studies, effectively alleviating the “strong point and weak surface” gas injection situation.
To ensure a safe and stable gas supply this winter and next spring, the field prepared in advance for the transition from the gas injection period to the gas extraction period, dynamically adjusted the gas injection and extraction operation plan, and finely formulated the gas extraction operation arrangement. The field also carries out a comprehensive risk and hidden danger investigation for the gas production process system, implements winter protection and insulation work in advance, and does a good job of commissioning production support equipment such as heating furnaces and electric heaters to ensure the safe and smooth operation of the gas production process during the peak-adjustment phase.
In order to actively implement ground construction protection measures, Jidong Oilfield accelerated the implementation of ground process insulation work, completed the injection and extraction valve set, metering skid, 8 gas production wellhead ground process heat insulation. Implementing measures to protect gas production wellheads from freezing and heating processes, improving the wellhead methanol injection process, organizing two new electric heaters on the island, and combining the existing electric heaters to provide heat load to meet the daily peak peaking production capacity of 400,000 cubic meters. Implement safeguard measures for the injection and extraction valve group process and process transformation, shut off the valves of the gas injection process, fix them with lead seals and put locks and hang tags on them to ensure isolation from the gas extraction process. Removal of the existing blocking blind for the gas extraction valve, installation of docking heater or heater into the gas extraction angle valve corresponding process, the organization of the gas injection well injection and extraction process conversion.
It is reported that the “Fourteenth Five-Year” period, Jidong oilfield will build 6 gas storage reservoirs, including Nanbu 1-29, Fort Gu 2, Nanbu 1-5 and Nanbu 2 Qianshan. When completed and put into operation, the Jidong Oilfield gas storage reservoir group will become the gas storage center in North China, effectively improving the natural gas peak regulation and supply capacity in the Beijing-Tianjin-Hebei region, which plays an important role in ensuring national energy security and promoting the economic development of the Beijing-Tianjin-Hebei region.