Chinanews Xining, April 2nd, Question: Exploring the Three "Oil Dragons" of Heroic Ridge in Qaidam Basin

Author Sun Rui Li Xiakui

On the oil and gas distribution map of the Qaidam Basin, oil fields large and small painted in red at the northwestern end of the basin are particularly prominent.

Since 2010, the three billion-ton reserves in Yingdong, Yingxi, and China have appeared on the top of the mountain—Hero Hero, which is more than 3,000 meters above sea level.

The picture shows the seismic exploration site of Qinghai Oilfield. Photo by Qinghai Oilfield

30-year exploration without scale discovery

The Qaidam Basin is China's highest inland basin with abundant underground resources and is known as the "treasure basin". According to the results of multiple oil and gas resource evaluations, the Heroic Ridge Tectonic Belt, located in the western Qaidam Basin, accounts for 30% of the total oil and gas resources in the basin, and has great potential for discovery.

Beginning in the early 1980s, CNPC organized several key research projects and cooperated with international oil companies. Over the past three decades, it has not been able to obtain valid underground information after 30 years of wheel-type exploration and research.

The picture shows the breakthrough of heroic oil and gas exploration, and the site of trial production, discharge and injection. Photo by Qinghai Oilfield

Why is it so difficult to find oil and gas in the Yingxiongling structural belt?

Under the action of the Himalayan tectonic movement, the area rapidly rises, folds, and deforms from the deepest part of the lake basin into mountainous areas within the basin, resulting in deep surface trenches and thousands of cliffs. The complex world and the conditions of high-altitude and low-oxygen conditions make exploration and construction difficult in the world. The mountain drilling rig used for seismic exploration is carried by people on their backs.

However, due to the vertical and horizontal gullies, the underground structure is deformed strongly, and the exploration work is difficult.

The picture shows the 2D seismic exploration site of Youquanzi in Qinghai Oilfield. Photo by Qinghai Oilfield

Unveiling the Mystery of Heroes' Ridge

In 1984, the older generation of exploration workers relied on heavy magnetic and electrical technology to drill a number of exploration wells in the Heroic Ridge structural belt. Although most of them failed, they shot the world's highest oil well Lion 20 in the depths of the western part of the British West. Initially Nissan Over 1,000 tons, it has shown great exploration potential.

In 2007, the state once again set up a major project to concentrate its strengths and form a team of more than 1,000 people-to-industry, research and research teams to face world-class exploration challenges.

Qinghai Oilfield Branch of China National Petroleum Corporation (hereinafter referred to as "Qinghai Oilfield") shifted from the main attack to the middle and shallow layers, and changed from fractured reservoirs to clastic reservoirs. After many discussions and studies, a “late reservoir accumulation on the source” model was constructed, and the exploration target was aimed at the relatively stable Yingdong shallow layer in the eastern section of the tectonic zone.

The picture shows the large-scale fracturing site of Zhahaquan tight oil in Qinghai Oilfield. Photo by Qinghai Oilfield

After careful demonstrations by scientific researchers, wells Sand 37 were drilled in 2010. Shallow oil and gas shows frequently and gratifying. Eventually, wells were completed in advance to explain more than 200 meters of oil and gas layers. The test oil obtained high-yield industrial oil gas flow but was only a few hundred meters away from Sand 101 But unexpectedly lost.

As a result, Qinghai Oilfield and Oriental Geophysical Experts identified a complex mountain field information acquisition scheme through a large number of experiments, and carried out targeted joint 3D seismic joint research in complex mountainous areas. The imaging of seismic data in the Heroic Ridge area achieved "from nothing to existence, from existence to precision" "A historic leap.

Since then, Yingdong Oilfield has declared a total of 120 million tons of oil and gas tertiary geological reserves, with an annual output of 470,000 tons, accounting for one-fifth of the crude oil production in Qinghai Oilfield. It is an important block for the stable production of crude oil in the Qaidam Basin. Become a successful example of efficient exploration.

More than 100 million "small goals"

The discovery of Yingdong Oilfield and major breakthroughs in technology have made researchers more enlightened.

Through a large number of simulation experiments, researchers have revealed that the salinity source rocks have the characteristics of multi-peak hydrocarbon generation, which has greatly increased the oil and gas resources in the basin from 1.58 billion tons of secondary appraisal to 7.03 billion tons, and the proved rate of oil is only 14.8%. For this reason, scientific research forces have gathered in Yingxi and Yingzhong, which are more difficult to explore in Yingxiong Ridge.

Qinghai Oilfield based on studies of fine-grained rock sedimentation, structural superposition analysis, and dynamic hydrocarbon accumulation process, has confirmed that the West-England-China is a high-pressure, high-yield tectonic rock that is a rare type of salted lacustrine carbonate carbonate multi-media reservoir at home and abroad. Oil and gas reservoirs have an in-source accumulation pattern of "integrated stratigraphic carbonate source and reservoir, connected fracture fractures, and large-area accumulation".

Supported by the established geological theory of hydrocarbon formation, storage and accumulation in the saline lake basin and supporting technology of “double complex” seismic exploration, 34 exploration wells were deployed in the West-British-Chinese Communist Party in three years, and 27 wells were successfully established, of which 9 were Rare Nissan "thousand-ton well". On the plane, six oil and gas high-production enrichment areas such as Shi 58 have been implemented. Among them, Shi Xin 58 well has a daily output of 100 tons and has maintained stable production for a long time. At present, the British West-British China has submitted a total of 160 million tons of equivalent tertiary oil and gas reserves, and the annual oil production has rapidly increased, with a cumulative production of 765,000 tons of crude oil.

After years of arduous research, geologists finally succeeded in "world-class exploration problems" and created the oil and gas geological theory and exploration technology sequence of the strongly transformed salted lake basin. It broke the 30-year exploration deadlock.

Qinghai Oilfield indicated that the three “dragons” of Heroic Ridge took off, demonstrating that there are still many more types of oil and gas reservoirs in the area that are yet to be discovered, and the boundary is far from being detected. With the continuous advancement of geology and engineering technology, prospecting workers are confident to continuously expand the size of the large-scale oil and gas area around the Heroic Ridge. (Finish)