On August 25th, China Petroleum held a press conference to announce the information of a major strategic breakthrough in the exploration of Gulong shale oil in Daqing Oilfield.
According to reports, Daqing Oilfield has deployed key exploration wells such as Guye Youping 1, Yingye 1H and Guye 2HC.Get more than 30 cubic meters of daily oil, high yield and stable trial production.Among them, Well Guye Youping-1 produced more than 500 days of oil breakthrough, accumulated more than 6,000 tons of crude oil, and accumulated nearly 10,000 tons of oil and gas equivalent, achieving a major strategic breakthrough in continental shale oil in Songliao Basin. On the plane, 43 vertical wells have produced oil, and 5 horizontal wells have achieved high production.In 2021, the oil-bearing area will be 1,413 square kilometers.The predicted geological reserves of new oil are 1.268 billion tons.Daqing Gulong shale oil will become an important strategic resource for the construction of Daqing oilfield in the past 100 years, which is of milestone significance to the sustainable development of Daqing oilfield.
Daqing Oilfield has been explored and developed for more than 60 years. Faced with the severe challenge of unbalanced storage and production and difficulty in stable production, Daqing petroleum people innovated unconventional exploration ideas, marched into the shale oil of Qingshankou Formation in Yuannei, strengthened the study of shale oil enrichment law and evaluation of enrichment layer, and tackled the problem of fracturing horizontal wells to increase production, and achieved great innovation in shale oil in-situ accumulation theory, major breakthrough in key engineering technology and great achievements in exploration practice.
Four breakthroughs have been made in theoretical understanding:
It is found that Gulong shale has a fracture-pore reservoir system controlled by foliation, which breaks through the traditional understanding of poor physical properties of shale reservoirs. It is found that the high clay shale has good oil-bearing property, which breaks through the traditional understanding that shale oil mainly exists in sandy and carbonate interlayers. It is found that the oil generation window of Gulong shale is wide, and it can still generate hydrocarbon mainly in liquid state at high maturity stage, which breaks through the traditional understanding that gas is the main source of Ro greater than 1.3%. The "extinction line" of water-sensitive mineral montmorillonite was discovered, which broke through the traditional understanding of poor compressibility of high clay shale. These breakthrough understandings have realized the leap from "oil generation" of continental shale to "oil production" of continental shale, and the leap from migration and accumulation of classical petroleum geology to in-situ accumulation of high organic shale.
Significant progress has been made in key engineering technologies:
Matching the template of drilling speed-up technology, the length of horizontal section is increased from 1500m to 2500m, and the drilling cycle is shortened from 113 days to 18.8 days. The main fracturing technology of "reverse mixing, current-limiting perforation and compound production increase" with Daqing characteristics was formed, and the compound production increase technology was innovatively developed. It took 33 days to complete the fracturing of 381 sections of 12 horizontal wells, and the factory construction capacity and construction scale were improved. The daily number of fracturing sections was increased from 3.5 to 8.2, and the fracturing construction time was increased by 50%.
By exploring production systems such as controlled pressure blowout and early pumping, oil production in wells such as Guye Youping 1 and Songye You1hf has been running smoothly for more than a year, which fully shows that Daqing Gulong shale oil has good stable production capacity. At the same time, we should objectively realize that the exploration and development of continental shale oil, as an unconventional resource type, is still facing a series of new challenges in theory, technology, cost and benefit, and it is necessary to further strengthen scientific and technological research and management innovation to realize the effective development of Daqing shale oil.
It is reported that Daqing Oilfield regards Gulong shale oil as an important strategic field and is making every effort to accelerate all work. In 2021, 100 wells will be implemented, 58 wells have been drilled, 27 wells have been tested, 25 wells have seen oil, and 17 wells have obtained industrial oil gas flow. The "14th Five-Year Plan" will increase the proven geological reserves of oil by 1 billion tons, and the annual output of shale oil will reach more than 1 million tons. (Headquarters reporter Guo Xiaoguang Liang Dong)