Successfully drilled 231 meters in a water depth of over 2000 meters, breaking the world record
Deep-sea drilling, "Manatee II" real cow (technological perspective)
Yu Sinan and Tang Yahui
The deep sea is rich in mineral resources. To discover and study them, it is necessary to obtain samples through underwater drilling.
Among various sampling methods, subsea drilling rigs have become the most popular high-tech equipment due to their advantages of low drilling cost, high efficiency, small sample disturbance, and easy operation.
Not long ago, my country’s self-developed "Manatee II" submarine large-hole deep pressure core drilling rig system successfully drilled 231 meters in a depth of over 2000 meters, breaking the world record for deep-sea submarine drilling rigs, marking my country’s presence in this area. The field has reached the world's leading level.
Looks cumbersome, but in fact it is extraordinary
Drilling below 200 meters means that my country theoretically has the exploration capability for full coverage of marine resources
"Manatee II" was researched and developed under the leadership of Professor Wan Buyan of Hunan University of Science and Technology.
According to Wan Buyan, "Manatee II" is composed of the submarine drilling rig body, the subsea in-situ sounder, and the supporting retracting and releasing system of the mobile subsea drilling rig.
"The appearance of the drilling rig is an orange-yellow, octagonal steel structure, with a height of 7.6 meters, a'waist circumference' of 10 meters, and a weight of 12 tons. It is currently the heaviest geological exploration equipment in the water in my country."
The seemingly cumbersome "Manatee II" is flexible when working on the seabed.
Its "weapon" is the 78 drill rods on the body, each 3 meters long, arranged on the disk like revolver bullets.
During operation, through the rotation of the disc, the manipulator takes the rods and loads them, and drills the drill rods one by one into the rock.
The drill bit is equivalent to the horn of "Manatee II" and is made of materials such as diamond and cemented carbide.
Researchers have designed different types of drill bits, some for hard rock formations, and some for soft rock formations in sedimentary rocks.
"Manatee II" was a world record set on April 7.
Wan Buyan told reporters that on the same day, after about two and a half hours of diving, the "Manatee II" reached the bottom of the sea at a depth of 2,060 meters.
After completing the posture adjustment, "Manatee II" immediately carried out the pressure-maintaining core drilling operation of the target layer.
About 15 hours later, the drilled hole reached a depth of 231 meters below the seabed.
In addition to drilling deeply, the "Manatee II" has a unique skill-pressure-keeping and core-taking.
This is the key to exploring certain seabed minerals such as combustible ice.
According to Wan Buyan, combustible ice is "ice" under the pressure of seawater. Once it leaves its proper depth of seawater, it will become volatilized due to the decrease in pressure.
Therefore, ordinary deep-sea drilling rigs cannot sample combustible ice, and can only do so while maintaining equal pressures on the seafloor formation.
Previously, the maximum drilling depth of the global subsea drilling rig was designed to be 200 meters, but the actual pressure-holding and coring operation was only 135 meters deep. The "Manatee II" has greatly set this record.
Through drilling and sampling analysis, it is possible to understand the mineral reserves, grade and burial form, and outline a "treasure map" for future mining.
"The deeper you drill, the more resources you can explore." Wan Buyan said that the current marine mineral resources discovered by humans that have commercial exploitation potential are basically within 200 meters of the seabed.
Drilling below 200 meters means that my country theoretically has the exploration capability for full coverage of marine resources.
According to the "United Nations Convention on the Law of the Sea", the high seas resources are shared by all mankind, and the right to exploit resources generally follows the rule of whoever explores and who has priority.
Experts in the industry said that "Manatee II" is a "sharp sword" for my country's deep-sea drilling. Its sheathing gives my country an additional technical advantage in the research and development of seabed solid mineral resources.
Overcome multiple technical problems
All key technologies are independently researched and developed, and 125 patents have been obtained so far
In the deep sea, the pressure is high and the temperature is low. The "Manatee II" must successfully implement a series of operations such as rig retracting and releasing, posture adjustment, pressure sealing, drill pipe and core tube connection and unloading, and automatic measurement and control in a complex environment, which is very technically difficult. Big.
According to Wan Buyan, "Manatee II" mainly overcomes technical problems such as whole-process pressure-holding rope coring, drill pipe storage and rapid drill pipe connection and unloading, intelligent and expert operating systems, and safe and reliable subsea drilling rig deployment and recovery.
During the drilling process, it is not difficult to achieve pressure holding and coring in a certain section, but the difficulty is to hold pressure throughout the process.
In response to this problem, scientific researchers have been tackling key problems for many years, using large-hole deep remote control full-hole pressure-holding rope coring, using the original core tube full-length direct sealing pressure-holding coring principle, technology and technology, and finally realized the seabed The drilling rig has small diameter and large hole depth, high efficiency, high reliability, full hole pressure keeping and core removal.
Wan Buyan said, "Manatee II" is "smart".
Researchers have customized a lot of sensor equipment for it.
These sensors incorporate the team's years of offshore field drilling experience.
When it reaches the seabed, the drill bit will quickly and automatically judge and adaptively adjust the drilling mode and parameters according to the formation conditions, which solves the adaptability of the seabed drilling rig and supporting coring technology to the complicated seabed formation, thereby greatly improving the drilling efficiency and coring. Rate and core quality.
Thanks to the automated and intelligent design, one person can complete the "Manatee II" operation on the mother ship.
The "Manatee II" can also perform "part-time jobs" while drilling cores: in-situ detection of the resistivity and porosity of the rock, and taking pictures of the surrounding rocks in the hole, etc.
In the design and technology of the submarine drilling rig retractable device, the team solved the problem of difficulty in aligning and approaching the submarine rig and retractable device due to the shaking of the mother ship, as well as easy impact and collision. The process automatically holds the subsea drilling rig function to improve the efficiency of subsea drilling rig retraction and release and the safety and reliability of the retraction process.
It is worth mentioning that all key technologies of "Manatee II" are independently developed and 125 patents have been obtained.
The development of "Manatee II" is based on the subject of my country's national key research and development plan "key deep-sea technology and equipment".
For the "Manatee II", the mission statement has three goals, namely, the operating water depth is not less than 2000 meters, the drilling depth is not less than 200 meters, and the pressure holding success rate is not less than 60%.
To Wan Buyan's delight, this sea trial fully verified the design performance of the "Manatee II" and achieved the mission goal beyond expectations.
Will continue to be optimized in the future
Challenge the 10,000-meter water depth geological drilling sampling is the next goal of the team
"Manatee II" is not "born out of the sky", but the result of more than 20 years of perseverance and continuous research and development.
In 2000, the Wanbuyan team began to develop deep-sea subsea drilling rigs.
Three years later, the team built my country's first deep-sea shallow core sampling rig, and drilled 0.7 meters below the sea floor to obtain the first core sample.
In 2010, the deep-sea deep-hole core sampling rig developed by the team further advanced the seabed drilling depth to 20 meters.
In 2012, the predecessor of the "Manatee II"-the "Manatee" development project was officially launched.
In 2015, the "Manatee" drilled 60 meters under 3000 meters of sea water.
As a result, my country has become the fourth country in the world that has the technology to drill 60 meters on the seabed with a depth of more than 3000 meters.
Nowadays, many marine scientific research ships in my country are equipped with patented equipment invented by the Wanbuyan team, and more than 1,000 boreholes have been drilled in the deep sea.
The development of submarine drilling rigs is closely connected with the exploration history of my country's submarine resources.
Wan Buyan told reporters that before 1999, China was unable to develop large-scale deep-sea electromechanical equipment and could only rent equipment from abroad.
Later, my country decided to independently research and develop deep-sea drilling equipment.
The Wan Buyan team rose to the challenge and took over the task.
They started almost from scratch, constantly fumbled, and courageously tackled problems.
In recent years, my country has paid increasing attention to the research and development of marine technology and equipment.
Deep-sea seabed drilling technology has strong radiation to other deep-sea equipment manufacturing technologies and can drive research and development in related fields.
Wan Buyan said that more than 10 years ago, basically all the equipment on board the scientific research ship was imported. Today, more than 80% of the domestically produced equipment has been made, and this proportion will increase in the future.
Wan Buyan said that the team will further optimize the performance of deep-sea drilling equipment and improve its environmental adaptability, operational performance and intelligence.
In addition, they also plan to promote the mass production of "Manatee II" and promote its application in the construction of submarine oil and gas fields, offshore wind farms, and engineering geological surveys.
Currently, the "Manatee II" is still working at sea.
The Mariana Trench, which has a depth of more than 10,000 meters, has so far no human beings engaged in seabed drilling operations.
"Challenging geological drilling and sampling in 10,000-meter water depths is the next goal of our team." Wan Buyan said.