CNOOC Ltd has announced that it has drilled and discovered a high-yield volcanic oil and gas well in ultra-deep formations over 5000 m deep in Bohai, marking a major breakthrough in ultra-deep natural gas exploration offshore China.
The well is located in central Bohai, adjacent to the Bozhong Sag, the largest hydrocarbon-rich sag in Bohai. It encountered a cumulative total of over 120 m of gas pay zone in volcanic formations, and was completed at a depth of 5770 m. The well was tested to produce approximately 800 000 m3/day (approximately 28 million f3/day) of natural gas, revealing promising exploration prospects in the offshore ultra-deep volcanic rocks and effectively promoting the natural gas exploration process in the Bozhong Sag.
The ultra-deep formations in Bohai are geologically complex, making reservoir prediction difficult. CNOOC Limited has continued to make breakthroughs in its theoretical understanding of offshore ultra-deep oil and gas exploration, independently developed key offshore deep multi-source broadband three-dimensional (3D) seismic exploration technologies, and developed innovative methods for predicting high-quality reservoirs in ultra-deep buried hills, precisely identifying the favorable ultra-deep volcanic natural gas enrichment zones in the Bozhong Sag, discovering a high-yield oil and gas well, and marking a significant breakthrough in ultra-deep volcanic natural gas exploration in Bohai.
Mr. Xu Changgui, Chief Scientist and Chief Geologist of China National Offshore Oil Corporation (CNOOC), said: “In recent years, CNOOC Limited has continued to strengthen theoretical innovation in deep and ultra-deep oil and gas enrichment in basins with high heat flow and strong activity, and to intensify research on key technologies. Exploration in China’s offshore areas has achieved a major leap from shallow to deep and ultra-deep formations. The success of this well has opened up a new play for offshore ultra-deep natural gas exploration and expanded the scope of deep oil and gas exploration in Bohai. It is of positive significance for accelerating the ultra-deep exploration process in Bohai and for building a major gas province of one trillion cubic meters in Bohai.”
