China's Offshore Shale Oil Exploration Has Made A Major Breakthrough

It was learned from CNOOC that the first offshore shale oil exploration well in China, Weiyan -1, was successfully tested by fracturing and obtained commercial oil flow, which marked a major breakthrough in offshore shale oil exploration in China.

Well Weiye -1 is located in the southwest depression of the Beibu Gulf in the South China Sea, with a daily output of 20 cubic meters of crude oil and 1589 cubic meters of natural gas and stable production capacity. According to estimates, the shale oil resources in Weixi 'nan sag reach 800 million tons, and the shale oil resources in the whole Beibu Gulf basin are about 1.2 billion tons, which shows a good exploration prospect.

It is understood that shale oil mainly refers to oil resources distributed in the pores of shale formation, 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 pore size of shale oil is as small as nano-scale, so it is extremely difficult to produce.

In recent years, with the development of conventional oil and gas in old oilfields entering the middle and late stage, China CNOOC has taken unconventional oil and gas exploration and development as an important direction for resource replacement and stable production. According to Deng Yong, chief geologist of China CNOOC Zhanjiang Branch, in the process of tackling key problems, the China CNOOC project team innovated the exploration idea of "integration of conventional and unconventional", repeatedly studied the characteristics of shale oil geological reservoirs in Wei Southwest, demonstrated the feasibility of engineering and fracturing for several rounds, and finally optimized the target area with good oil-bearing and fracturability, and deployed Well Wei -1.

In view of the geological characteristics of the sandy zone in the fractured zone in the target area, the project team used the special fracturing technology of "high-low viscosity integrated seawater-based variable viscosity fracturing system+current-limiting perforation+pressure-controlled flowback" to release the production capacity, and successively completed the testing operations of two types of shale oil sections, namely, interbedded shale oil section and interbedded shale oil section, all of which were commercially discovered.

General manager of China Offshore Oil Exploration Department, said that the success of the first offshore shale oil is a major breakthrough in offshore oil and gas exploration, which has realized the independent exploration and development of China's offshore shale oil and gas resources with our own equipment and technology, and opened the prelude to unconventional offshore oil and gas exploration and development, with huge resource potential, which has consolidated the resource base for firmly holding the energy rice bowl in our own hands.