“This is the first exploration and development of shale oil in the Qinghai Tibet Plateau. At present, the well controlled oil-bearing area is 42 square kilometers, which is expected to form considerable large-scale reserves and provide long-term resource support for energy security.” On the 28th, Zhang Qinghui, deputy manager of yingyingling shale oil project department, told China News Agency.
On the same day, Qinghai Oilfield Branch of Petrochina Company Limited(601857) natural gas group company (hereinafter referred to as “Qinghai Oilfield”) held the launching ceremony of hero ridge shale oil project department and the drilling ceremony of Yingye 1H pilot test platform in Ganchaigou area. The launching of the project is also the first large-scale development of shale oil in the Qinghai Tibet Plateau.
Qinghai Oilfield is the highest oil and gas field in the world and one of the earliest developed oilfields in China. Qaidam Basin, located in the northwest of Qinghai Province, is an important oil and gas production base in Qinghai, Tibet, Gansu and Ningxia, with an average altitude of about 3000 meters. Ganchaigou area is located in the middle of the heroic ridge structural belt in the west of Qaidam Basin, adjacent to Yingxi oilfield in the West and Xianshuiquan oilfield in the East. The ground is mainly wind eroded mountains with high mountains, steep slopes and vertical and horizontal gullies, with an average altitude of 3200m to 3800m.
The exploration in this area began in the 1950s and experienced three processes: shallow to deep, clastic to carbonate, structure to lithology and conventional to unconventional. It is reported that since 2021, the shale oil exploration and development stage has been fully entered. In the early stage, 17 wells (15 vertical wells and 2 horizontal wells) have been deployed in accordance with the principle of “controlling the scale of vertical wells and increasing the production of horizontal wells”. The drilled vertical wells have seen active oil and gas in the well section up to 1200 meters. Up to now, 8 vertical wells and 11 layers have been tested, and industrial oil flow has been obtained.
“The biggest difference between the exploitation of shale oil and other reservoirs is that other reservoirs are put into production naturally, and the oil will gush out like spring water after well completion and perforation. The shale oil reservoir is very dense, and the crude oil is enriched in micro nano pores. We must use large-scale volume fracturing to liberate the oil, which is equivalent to making a high-speed channel underground to let the oil flow out.” Zhang Qinghui said.
Cui Ronglong, deputy director of the Development Office of the third oil production plant of Qinghai Oilfield, said that through the production of exploration wells in the early stage, it is concluded that shale oil vertical wells and horizontal wells have the characteristics of high initial production, stable pressure and long-term spontaneous flow stable production, laying the foundation for efficient development in the later stage.
“At present, there are nearly 1500 square kilometers of oil and gas reserves in the Yingling depression. At present, it has a shallow oil and gas exploration area of nearly 5000 square kilometers.” Zhao Jian, the whole life cycle project manager of yingyingling shale oil, told reporters, “our current experimental stage is basically to build a demonstration platform with a capacity of 100000 tons. The project will be carried out in three stages and gradually build a digital shale oil high-efficiency development demonstration zone with a capacity of 1 million tons.”
