Chinese state-owned oil and gas giant China National Offshore Oil Corporation (CNOOC) has made a high-yield natural gas discovery in volcanic rock more than 5,700 meters beneath the central Bohai Sea, opening doors to a new frontier for ultra-deep exploration in the region and bringing the company one step closer to building a trillion-cubic-meter gas province off the coast of China.
CNOOC has drilled a high-yield volcanic oil and gas well in ultra-deep formations over 5,000 meters deep in Bohai, said to represent a major breakthrough in ultra-deep natural gas exploration offshore China.
The well, which is adjacent to the Bozhong Sag, the largest hydrocarbon-rich sag in Bohai, encountered a cumulative total of over 120 meters of gas pay zone in volcanic formations and was completed at a depth of 5,770 meters.
The well was tested to produce approximately 800,000 cubic meters (around 28 million cubic feet) per day of natural gas, uncovering promising exploration prospects in the offshore ultra-deep volcanic rocks and promoting the natural gas exploration process in the Bozhong Sag.
"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."
While the ultra-deep formations in Bohai are geologically complex, making reservoir prediction difficult, CNOOC has continued to make what it describes as breakthroughs in its theoretical understanding of offshore ultra-deep oil and gas exploration.
The company independently developed key offshore deep multi-source broadband three-dimensional (3D) seismic exploration technologies and innovative methods for predicting high-quality reservoirs in ultra-deep buried hills.
The Chinese player points out that its efforts enabled it to identify the favorable ultra-deep volcanic natural gas enrichment zones in the Bozhong Sag, discovering a high-yield oil and gas well, and marking significant progress in ultra-deep volcanic natural gas exploration in Bohai.