China Petroleum & Chemical Corp. (Sinopec) drilled the Yuanshen-1 risk exploration well in Sichuan basin to a depth of 8,866 m, beating the previous deepest record in the basin set by the Rentan-1 well.
The well reached the mound-shoal complex of the platform marginal facies in the Dengying formation. It is the deepest oil and gas formation in the basin. During the exploration, the ultra-deep carbonate rock, buried at a depth of over 8,700 m, still showed positive hydrocarbon evidence in the porous reservoir.
Drilling to a depth of over 8,000 m required large-size upper casing which weighed 517 tonnes at ground level.
Sinopec has been exploring conventional gas in deep marine carbonate rocks and deep shale gas hydrocarbons in Sichuan basin. It discovered Puguang, Yuanba, and Chuanxi gas fields (OGJ Online, Nov. 28, 2022). To date, the company said, annual conventional gas production capacity from deep marine carbonate reservoirs has exceeded 12 billion cu m.