NEWS CENTER

Home page

2022

Major breakthrough in China's offshore shale oil exploration

CNOOC was informed that on July 28, the Weipag-1 well, China's first offshore shale oil exploration well, was successfully fractured and tested for commercial oil flow, marking a major breakthrough in China's offshore shale oil exploration.
　　
The Weipag-1 well is located in the Weixinan Depression in the Gulf of Tonkin area of the South China Sea, producing 20 cubic meters of crude oil and 1,589 cubic meters of natural gas per day with stable production capacity. According to the estimation, the shale oil resources of Weixinan Depression amount to 800 million tons, and the shale oil resources of the entire Beibu Gulf Basin amount to about 1.2 billion tons, showing a good prospect of exploration.
　　
It is understood that shale oil mainly refers to petroleum resources distributed in the pore space of shale strata, which is a typical unconventional oil and gas and a strategic replacement field for conventional oil and gas. Compared with conventional oil and gas, the pores of shale oil are as small as nano-scale, which makes it extremely difficult to extract.
　　
In recent years, as the conventional oil and gas development in old oil fields has entered the middle and late stage, CNOOC has taken the exploration and development of unconventional oil and gas as an important direction for resource replacement and production stabilization and increase. According to Deng Yong, Chief Geologist of CNOOC Zhanjiang Branch, in the process of research, CNOOC's project team innovated the idea of "integration of conventional and unconventional" exploration, repeatedly studied the geological reservoir characteristics of Weixinan shale oil, repeatedly proved the feasibility of engineering and fracturing, and finally selected the target area with good oil content and fracturable transformation, and deployed the Weixinan shale oil well. Shale-1 well was deployed.
　　
In response to the geological characteristics of sandy stripes in the target area, the project team adopted the special fracturing process of "high and low viscosity integrated seawater-based variable viscosity fracturing system + flow-limiting injection + pressure-controlled rejection" to release the production capacity, and successively completed the testing operation of two types of shale oil sections, namely interbedded and intercalated, which both made commercial discoveries.
　　
Xu Changgui, general manager of the exploration department of CNOOC, said that the success of the first offshore shale oil is a major breakthrough in offshore oil and gas exploration, realizing the independent exploration and development of China's offshore shale oil and gas resources with our own equipment and technology, opening the prelude of offshore unconventional oil and gas exploration and development, with huge resource potential, and solidifying the resource base for putting the rice bowl of energy firmly in our own hands. (Qiu Yue)