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Energy security and security are related to the national economy and people's livelihood, and can not be ignored for a moment. Deep and super deep have become the main positions of oil and gas exploration in China, and the oil and gas resources account for 34% of the total oil and gas resources in the country. Among them, Tarim Basin is one of the basins with the greatest potential in increasing onshore oil and gas storage, and the oil and natural gas resources with a depth of more than 6000 meters account for 83.2% and 63.9% of the country, respectively. At present, the exploration and development of Tarim Basin has fully entered the ultra-deep layer, and the largest ultra-deep layer oil and gas production base has been built in China.
Shaya County, Xinjiang. In Taklimakan in August, the heat wave is rolling and the sand is long. From time to time, visible haloxoul, red willow, stubborn drill out of the ground, and the wind and sand launched a tenacious contest. In the boundless sand sea, the road is winding, the car is bumping, and the grass grid is trying to bind the continuous dunes. As far as the eye could see, wires stretched out into the distance. The drilling and station houses that flash by the roadside from time to time mark the track of the extension of the underground oil and gas pipeline network. China's first 10,000 meters deep geological exploration well, the depth of exploration constantly refreshed; Oil and gas exploration day and night at the "Deep Earth No. 1" project site. This once desolate sand sea is now surging with the pulse of energy flowing.
There are more than 100 deep Wells with a vertical depth of more than 8,000 meters
After bumping along the gravel road for a long time, in the distance, I saw a huge red-and-white derrick standing on the horizon. Approaching, the sound of the drilling rig was deafening. Drilling, cementing, logging... Workers in red uniforms are fighting hard under the hot sun.
The active board room next to the derrick is the intelligent command platform, and the large screen is dense with construction parameters and multiple real-time monitoring videos, intuitively displaying the progress of drilling.
"At present, the well has been drilled to 5,856 meters." Wang Chunsheng, chief technical expert of petrochina Tarim Oilfield Company, is quick to speak.
Through the video, you can see the center of the drilling operation - the driller's room. The driller is holding the brake in his hand, staring at the large screens in front of him, concentrating on the operation, and the drill pipe is turning and digging thousands of meters underground...
At the same time, on the edge of a tenacious poplar forest, Sinopec's "Deepi No. 1" leaping 3-3XC well is advancing 9000 meters underground.
"There are three Wells on the site, two of which are already in production, and the one under construction is the 3-3XC well." According to Zhang Yu, representative of Sinopec Northwest Oilfield Company, the design depth of the well has reached 9,472 meters, and as of August 21, it has been drilled to 8,273 meters.
In the Tarim Basin, because most of the oil and gas reserves are less than 6,000 meters deep, there are many drilling Wells like this deep into the earth. According to statistics, the number of Wells over 6000 meters deep in petrochina Tarim Oilfield has reached more than 1700, accounting for more than 80% of the country, of which more than 8000 meters deep Wells have been successfully drilled more than 100; Sinopec has drilled 57 oil and gas Wells with a vertical depth of more than 8,000 meters in the Tarim Basin.
As the largest deep-earth oil and gas rich area in China, the sand sea of Taklimakan has become the largest ultra-deep oil and gas production base in China, with the discovery and development of Fuman, Keshen, Shunbei and other large oil and gas fields. Through long-term exploration, it has formed 9,000 meters of drilling and completion, oil testing and reconstruction, logging and other engineering supporting technologies, and cultivated a professional team covering oil and gas geology, geophysics, drilling and completion, reservoir reconstruction, testing, logging and other aspects of ultra-deep oil and gas exploration and development.
Tackle key problems——
Localization of key technologies and equipment
A deep way is difficult. In general, the industry defines the depth of 4,500 meters to 6,000 meters as deep Wells, 6,000 meters to 9,000 meters as ultra-deep Wells, and more than 9,000 meters as ultra-deep Wells. The ability to push the well depth to several thousand meters depends on the overall improvement of China's industrial manufacturing capacity. China's equipment manufacturers have broken the foreign technology monopoly, developed a number of key core technology and equipment, and achieved the leap from "not playing" to "playing fast and playing accurately".
The design depth of deep Tako 1 well is 11,100 meters, which is the first 10,000 meters deep exploration well in China, and the expected drilling cycle is 457 days. At present, more than half of the drilling has been completed in only tens of days, but the total progress of the drilling project is only 10%.
"After reaching a certain depth, the difficulty increases exponentially with each meter down." Duan Yongxian, manager of petrochina's Tarim Oilfield exploration division, said, "The deeper you dig, the higher the pressure and the higher the temperature. Under high temperature and pressure, the drill pipe is as soft as cooked noodles, and at a depth of more than 10,000 meters, it has to face ultra-high temperatures of over 210 degrees Celsius and ultra-high pressures of 130 mpa."
A set of drilling equipment can be roughly divided into a drill, a drill bit and a drill pipe connecting the two.
Drilling rig is the "power heart" of deep well engineering. The deep-ground Taco 1 well uses the world's first 12,000-meter deep well automation drilling rig independently developed by China. The rig is 72 meters tall, the equivalent of a 24-story building. Zhang Maosheng, head of field service of China Petroleum Gem Machinery Co., LTD., told reporters that compared with ordinary drilling RIGS, the load lifting capacity has been increased from three or four hundred tons to 900 tons, and 150 adult elephants can be lifted at the same time.
The drill provides a lot of power, and it's the drill that comes up against the underground rock. At the 3-3xC well site of Shendi 1, more than 10 kinds of drill bits are on display. "Now our drill bits are widely used in deep drilling in China, and the cost has been reduced by half compared with imports." Li Jinfeng, deputy manager of the Second drilling company of Sinopec Jianghan Petroleum Engineering, said, "The blue bit is a cone bit, which can rotate in addition to being driven by the drill pipe, and the three cones in front of it can also rotate and cope with a variety of different formations." Next to this gold is the PDC (polycrystalline diamond composite sheet) bit, which has very hard artificial diamond 'teeth' attached to it, which can chip away at hard rock."
How exactly do you find oil and gas in "deep, dark" ground?
A metal pole in one corner of the construction site caught the reporter's attention. "These metal rods are equipped with measurement and control instruments while drilling. After iterative upgrades, they can adapt to the high temperature of 200 degrees Celsius, and can transmit drilling signals below 8,000 meters to the surface in real time. It is like installing eyes on the drill bit and adjusting the drill track at any time." Sinopec Northwest oilfield Research Institute of petroleum engineering technology drilling institute engineer Yang Weixing introduced.
Unlike conventional drilling, Deepearth-1 jumped into the 3-3XC well and made a big bend a few kilometers down. Since the oil and gas resources are located under the wetland nature reserve in the upper reaches of the Tarim River, drilling must be done vertically outside the ecological protection area, and then horizontal drilling of more than 3400 meters. "This applies our ultra deep extended reach drilling technology. "Conventional drilling is like a straw going down to the bottom. Here it's like an L-shaped straw going down to the bottom and then extending laterally." Yang Weixing made a vivid analogy.
Challenge the limits of deep earth with technological innovation
Ultra-deep well drilling is the field with the most bottlenecks and challenges in oil and gas engineering technology, and it is necessary to face extremely harsh conditions such as ultra-high temperature, ultra-high pressure and easy formation collapse. And in the Tarim Basin, but also face "only in China, the world's rare" underground rock formation combination. After hundreds of millions of years of crustal movement, the Tarim Basin's strata have become fragmented, and its structure has been likened by geologists to "a pile of plates that have been broken and kicked."
"Of the 13 difficulty index coefficients of drilling and completion projects recognized in the world, 7 indicators in the Tarim Basin rank first, and other indicators are also in the forefront, and the comprehensive difficulty is rare in the world." Deep earth exploration here is a multi-disciplinary and systematic project involving geology, geophysical exploration, engineering and drilling." Wang Chunsheng said.
Looking for oil and gas resources in such deep and complex formations is like looking at a cruise ship on the Brahmaputra River from the top of Mount Everest. How do you know where the oil and gas resources lie underground?
In recent years, relying on major scientific and technological projects, China has made a series of innovative achievements in both geological theory and engineering technology, and has initially formed the hydrocarbon geological theory of deep-ultra-deep hydrocarbon formation - reservoir-accumulation, laying the foundation for the exploitation of oil and gas resources at 10,000 meters deep. At the same time, relying on the world's leading three-dimensional geophysical exploration technology, researchers can "see" the formation structure where the well location is located, which is equivalent to a "CT" for the formation, so that the underground criss-cross oil and gas vein is more clear.
"Even with systematic scientific support, drilling is sometimes like 'opening a blind box.'" "At present, the success rate of our exploration Wells can reach more than 50 percent, much higher than the world average of 30 percent, while the success rate of development Wells is 100 percent," Zhang said.
"For the deep-ground Tako-1 well, there are still many blank areas for drilling 10,000 meters deep, many mechanisms are still unclear, and there will be unpredictable mutations." But from theory to technology to equipment, there has been great progress, and we are confident that we can hit this well soon." Wang Chunsheng said.
At the site of the Deep Tako-1 well, a row of wooden boxes contains a lattice of rock debris, numbered by the depth of the formation.
In addition to oil and gas discovery, the Deep subsurface Tako-1 well also shoulders the task of scientific exploration. These drilling holes to the depths of the Earth are like probes, exploring the secrets of the depths of the strata, solving the internal structure and evolution of the Earth, providing further important data support for earth science research, and enriching our understanding of this planet.