This project belongs to the fields of "Mechanical Equipment Vibration, Noise and Life" and "Petroleum Engineering Technology".
With the acceleration of the development of oil and gas resources in deep formations, there are more and more deep wells (well depth 4,500 -6000m), ultra-deep wells (well depth>6000m) and directional inclined wells in my country year (currently, more than 90% of my country's oilfields are developed in directional inclined wells, while more than 92% of oil and gas wells in Tarim Oilfield are drilled in ultra-deep wells). This feature makes the operation safety of oil string in my country face serious challenges. For ultra-deep wells, the dynamic failure of drill strings is very prominent, with a failure frequency as high as 20.3%, which not only causes huge economic losses (the investment in single well drilling reaches 200 - 400 million yuan), but also seriously restricts the exploration and development process of oil and gas resources. For directional inclined wells, eccentric wear of the sucker rod string is very prominent, which not only has high workover costs, but also seriously affects crude oil production. The core reason for the above problems is that the dynamic safety of oil pipe strings (with ultra-long-thinness ratio and dual nonlinear characteristics) has not received due attention.
In response to this issue, with the support of 20 projects from the National Natural Science Foundation of China, the Ministry of Science and Technology, the Municipal Science and Technology Commission and oilfield enterprises, our team has carried out research work on "Dynamic Safety of Ultra-Deep Drilling String" and "Dynamic Anti-Eccentric Wear of Pumping Rod String in Directional Wells". Through nearly 10 years of research, innovative results have been achieved in three aspects:

1. Taking into account the ultra-long-thin ratio and dual nonlinear characteristics of the actual pipe string, a new node iteration algorithm for pipe string dynamic characteristics based on curved beam elements is proposed, and the dynamic characteristics of drill string in ultra-deep wells above 7000m are obtained for the first time; The dynamic safety evaluation method for ultra-deep well drill strings was invented, the Tarim Oilfield ultra-deep well drill string auxiliary design system was developed, and the dynamic safety design, evaluation and monitoring technology for ultra-deep well drill strings was formed, which effectively reduced the failure frequency of ultra-deep well drill strings., greatly improved the safety of drill string operations.
2. Forming supporting technologies for dynamic efficiency improvement and safe drilling of petroleum drill strings: ① innovatively proposed a pre-bent pendulum well deviation control method, and formed a dynamic method for ultra-deep well control and fast drilling technology and gas drilling well deviation control., solving the two problems of well deviation control and casing running difficulties for gas drilling in extremely thick gravel layers, breaking through the bottleneck that restricts the development of efficient speed-up technology for gas drilling in oil fields; ② A high-efficiency hydraulic cleaning drilling tool for cuttings beds was designed, and a high-efficiency cutting bed cleaning technology was formed, which effectively reduced friction and improved the operating efficiency of long-reach wells.
3. Formed a dynamic anti-eccentric wear and energy-saving technology for sucker rod strings: ① Breaking through the harsh assumption that the original technology emphasized the centring of the string, an analysis method and optimization design technology for the dynamic characteristics of the sucker rod string based on the actual spatial configuration of the string are formed;② innovatively proposed a method for determining the lower boundary conditions of the sucker rod string;③ proposed a method for predicting the position of severe eccentric wear points, forming a dynamic anti-eccentric wear technology for sucker rod strings.
   Through research, dynamic safety evaluation of ultra-deep well drill strings, anti-eccentric wear in directional wells, deviation control technology for gas drilling and debris bed removal equipment for long-reach wells with independent intellectual property rights have been formed. 3 invention patents and utility model patents have been authorized. 2, 5 invention patents have been applied, and 32 papers have been published. The scientific significance and application value of the original results of this project were highly praised by Academicians Su Yinao and Gao Deli. Part of the content won the second prize for scientific and technological progress by China Petrochemical Federation.
   The research results have been promoted and applied in more than 3000 wells in 9 oilfield companies, including PetroChina, Sinopec and CNOOC. In the past three years, 2887 wells have been promoted and applied, producing direct economic benefits of 2.379 billion yuan.
   Through tackling key problems, it has effectively promoted the development of our school's mechanics discipline, formed a research team featuring petroleum pipe column dynamics and a characteristic direction for the construction of 211 disciplines at Shanghai University, and effectively strengthened the construction of Shanghai City's key laboratory of "Application of Mechanics in Energy Engineering". Construction, training 2 young teachers, 6 doctoral students, and winning 1 outstanding doctoral thesis in Shanghai City. A group of technical talents have been cultivated for the oil field, which has effectively promoted the safe production of my country's petroleum engineering and the research and development of new drilling tools.