Drilling of my country's first Wanmike exploration well, Shenzhen Tako 1 Well, is in progress. The drilling site is located in the hinterland of the Taklimakan Desert in Xinjiang. Since drilling started on May 30 last year, after more than 200 days of drilling, we are working hard to advance to 10,000 meters.

　　As of 9 a.m. today, the Shenzhen Taco 1 Well has been drilled to 9,969 meters underground. According to the latest progress learned by the reporter, the current drilling speed is about 0.5 meters per hour. The drill bit is breaking through the barriers of underground hard rock and heading toward the last 30 meters of the 10,000-meter stratum.

　　Domestic drilling "blood" challenges the depth of 10,000 meters for the first time

　　Drilling fluid is known as the "blood" of drilling. During the drilling process of the first Wanmike exploration well, my country independently developed a drilling fluid system suitable for ultra-high temperature and ultra-high pressure formations, which became a powerful tool to overcome the drilling problems of ultra-deep formations.

　　Drilling fluid has many functions such as carrying cuttings, balancing formation pressure, and cooling the drill bit. A few days ago, this 10,000-meter-deep well used domestic drilling fluid to successfully deal with the vicious leakage underground, creating good conditions for further drilling.

Yin Da, a senior expert at PetroChina Tarim Oilfield Drilling Fluid Company:

At present, the new high-temperature resistant water-based drilling fluid technology in Deep Tako 1 Well, which is composed of all domestically produced materials, has passed the practice in harsh working conditions at an ultra-deep depth of 10,000 meters. After inspection, it fully meets the design requirements for ultra-high temperature resistance of 220°C. In the next step, we will continue to tackle key problems and develop towards ultra-high temperature levels above 240°C to further meet the needs of drilling operations in deeper parts of the earth.

　　The bottom of a well with a depth of 10,000 meters reaches an ultra-high temperature of 220°C and an ultra-high pressure of 150 MPa. Just like a pressure cooker, all food will be cooked to death in the high-temperature and high-pressure environment. If the drilling fluid has insufficient resistance to temperature and pressure, it will decay and deteriorate. Once its performance deteriorates, complex underground accidents will occur.

Yin Da, a senior expert at PetroChina Tarim Oilfield Drilling Fluid Enterprise:

conducted thousands of experiments, selected and developed hundreds of materials, optimized dozens of formulas, formed seven or eight sets of plans, and finally demonstrated and determined two sets of drilling fluids. Of the technical solutions, one is being implemented on site and the other is on standby. So far, we have struggled to overcome the geological complexity of twelve different formations, and have overcome a series of technical problems such as vicious well leakage, severe collapse, high-temperature corrosion, high-temperature blistering, and high-temperature thickening. We are working step by step to achieve "zero complexity" , zero accident” achievement, approaching the 10,000-meter mark.

　　Previously, Tarim Oilfield relied on its self-developed deep well drilling fluid technology system to successfully support the drilling operations of 139 ultra-deep wells exceeding 8,000 meters, providing strong drilling fluid technical support for drilling to depths of 10,000 meters.

　　Thousand-meter deep drilling tools withstand extreme tests

　　The closer the drilling depth is to a depth of 10,000 meters, the more severe the underground working conditions become. Drilling tools are always subjected to extreme challenges. Engineering and technical personnel always monitor the operating status of downhole drilling tools to ensure drilling safety.

　　There are currently 1,026 drilling tools in use underground. The drilling tools themselves weigh more than 350 tons. The drilling tools rotate and drive the drill bits to break the rock. The whole process is like twisting a twist on a length of 10 kilometers. Ultra-high loads, ultra-long distances and strong underground vibrations subject drilling tools to severe tests.

Lu Qiang, Senior Technical Expert of Drilling Tools at PetroChina Tarim Oilfield:

After the deep-sea Taco 1 Well drilled to 9,000 meters, we would find different numbers of fatigue cracks in the threads of the drilling tool every time we drilled. Sometimes one or two, some If the cracks are not discovered in time, they may break and cause serious accidents.

　　Lu Qiang told reporters that the drilling process is close to 10,000 meters, the state of motion and stress is extremely complex, and energy transfer is extremely difficult. Fatigue cracks have been found in 43 drilling tools on the well.

Lu Qiang, senior technical expert of drilling tools in PetroChina Tarim Oilfield:

There are more than 1,000 drills with more than 2,000 joints, and there must be no problem with any of them. The threaded joints of drilling tools are prone to failure. We strictly control the cumulative use time and strengthen monitoring. Make sure the drilling tools are safe.

　　(CCTV reporter Zhu Jiang, Zhang Wei, Gu Junling, Zhang Congjing and Tang Zhijian)