After breaking through 9,900 meters, the Deep Earth Tower 1 well is on the verge of penetrating the oil and gas cap rock, advancing towards the reservoir where oil and gas are stored.
China's first 10,000-meter deep well is poised to penetrate the oil and gas cap rock.
The oil and gas cap rock is the geological layer that seals off oil and gas reserves. Locating the cap rock is one of the fundamental geological conditions for finding oil and gas resources. It's akin to a blanket or lid securely covering the oil and gas, and to access these resources, the cap rock must be drilled through.
Yang Guo, Project Manager of the Basic Research Department at the Research Institute of Exploration & Development, Tarim Oilfield, PetroChina: Oil and gas resources underground are like layers of a sandwich - there's a cap layer on top, then the reservoir layer containing oil and gas, and below that, the source rock layer. The drilling of Well Ta-1 into the oil and gas cap layer since February 1st is excellent news. It indicates that at a depth of ten kilometers, the basic conditions for oil and gas sealing are present. There could be significant reserves of oil and gas underground, waiting for us to explore.
This formation has a hard upper layer and a soft lower layer, with frequent lithological changes making drilling extremely challenging. To overcome this formation, engineers have established a lithological composite model through macro and microstratigraphic correlation. By accurately selecting drilling tools such as drill bits, it took over 10 days to penetrate this formation covering oil and gas reservoirs. This marks the beginning of drilling towards potentially oil and gas-rich strata.
Director of Exploration Department, Tarim Oilfield Exploration Division, PetroChina, Mr. Lu Xiaogang: Once the drill bit penetrates the oil and gas formation, it may encounter even harder and more brittle formations, making the drill bit "bite harder bones" than usual, leading to greater wear and tear. At this point, the high temperature, high pressure, high ground stress, and unknown formation information will bring a lot of uncertainties to the drilling process.
Currently, the frequency of underground rock analysis and testing has been increased, and drilling parameters are adjusted promptly based on rock information to ensure safe and smooth drilling in formations up to ten kilometers deep. Presently, this well has reached a depth of 9,920 meters, and it is about to penetrate the ten-thousand-meter mark.
The Difficulty of Drilling Ten-Thousand-Meter Formations from the Perspective of Drill Bits The rocks beneath the vast expanse of shifting sands have been deposited for millions of years. To create an oil and gas pathway between these rocks, one must overcome extremely high temperatures, pressures, and ground stresses. How difficult is it to drill a ten-thousand-meter deep well? Let's make a comparison between new and old drill bits.
Technicians explained to reporters that as the drill bit penetrates deeper into the formation, the rocks become more compacted, exerting greater pressure on the drill bit from all directions, while the temperature continues to rise, resulting in increased wear and tear on the drill bit.
Zhang Zhi, Deputy Manager of the Exploration Division of PetroChina Tarim Oilfield: The drill bit, from the surface to a depth of 1800 meters, is basically intact with minimal wear. From 1800 meters to over 5800 meters, with an advancement of 4000 meters, there is also little wear and tear. In other words, the upper conventional formations pose minimal damage to the drill bit.
According to reporters, it took nearly five months to drill the Deep Tower Science 1 well from the surface to a depth of 8000 meters, while it will take three and a half months to drill from 8000 meters to ten thousand meters. As the drilling depth increases, the difficulty of drilling will also increase exponentially.
Zhang Zhi, Deputy Manager of Exploration Department at PetroChina Tarim Oilfield: The closer to the surface, the shallower the layer, these drills can penetrate up to five to six hundred meters in a day. However, as we go deeper to 9000 meters, the drill can only progress by a little over ten meters a day. So, the deeper we go, the more severe the damage to the drill, and the more difficult it becomes with each step forward.
Domestically produced diamond drills: Breaking through rock at depths of ten thousand meters
There's a saying in the oil industry: "No drill, no gas." This holds particularly true for drills reaching depths of ten thousand meters and beyond. In recent years, as Chinese oil and gas exploration ventures deeper into the subterranean, a large number of domestically produced diamond drills, tailored for various underground formations, have been developed and manufactured, becoming formidable weapons for conquering ten-thousand-meter strata.
As of 14:00 on the 14th, the latest diamond drill, which has been installed, has been drilling underground for 54 hours with all drilling parameters stable. This new drill is a 7-blade diamond drill, notable for its enhanced impact resistance.
Engineer Wen Liang from the PetroChina Tarim Oilfield Oil and Gas Engineering Research Institute: Currently, at a depth of 9900 meters underground, the strata consist of alternating soft and hard layers. There are very soft gypsum rocks that crumble with just a touch, as well as extremely hard flint, with hardness second only to diamond. Drilling underground is akin to eating persimmons, with the flesh being soft and the core being hard. The drill bit requires significant force, as otherwise, it could break teeth instantly. With our new drill bits, there are many teeth, ensuring more uniform force distribution and smoother drilling operations.
The drilling bits used in China's first 10,000-meter-deep well, which tackles challenging geological formations, are all independently developed. These diamond bits not only possess exceptional wear resistance but also demonstrate excellent toughness and impact resistance. Currently deployed bits can withstand pressure up to 80,000 atmospheres, equivalent to the pressure generated by eight 10-ton elephants standing on a thumbnail.
Lü Xiaogang, Director of the Project Department of the Exploration Division of the Tarim Oilfield of China Petroleum: "Currently, in our well, we have used 27 drill bits. After reaching a depth of 8000 meters, 14 of these drill bits are domestically-produced diamond drill bits. Through drilling into a ten-thousand-meter deep well, we have proven that our domestically-produced drill bits can meet the demand for drilling to such depths."
(Original Title: "China's First Ten-Thousand-Meter Deep Well is About to Penetrate Oil and Gas Reservoirs! Domestically-produced Diamond Drill Bits Become Rock-breaking Artifact")
