In the marine flatbed, nuclear power stations and oil fields, the marine risers and heat exchangers are induced vibrations and collision, even caused failure with cross flow. This is a typical problem of bundles vibration in fluid-structure interaction. In this paper, the elastic pipe was separated into several beam elements. And the dynamical equation was adopted to describe the structure. The fluid domain of cylinder was separated into solid elements. And the computational fluid dynamics equation was adopted to describe the fluid. At the fluid-structure coupling interface, the formulas of displacement, velocity and load was derived and the corresponding convergence criterion was also derived. Thus, the partitioned coupling algorithm was established for the elastic pipe and the cross-flow in cylinder. The example showed that, comparing to the results of monolithic coupling algorithm, the error was small. Thus, it proved that the correctness of the partitioned coupling algorithm in this article. And it will provide an effective computational method for vibrations and collision of bundles in a more complex fluid domain.

The design and mechanical analysis of fracturing string was one of the key technical problems in fracturing operation. Considering contact friction and curvature effect, contact nonlinear problem of fracturing string was solved by space beam element and multidirectional contact gap element method. Contact state, contact reaction force and corresponding frictional resistance between the fracturing string and borehole or inside casing wall could be accurately described by gap element, which generated less simplification in the mechanical model and more precise calculation of force and deformation. The calculations of field examples has shown that while the distance is 10 m, 20 m or 30 m between two packers of fracturing string, maximum axial sliding displacement of the first packer is 0.19 mm and sliding displacement of the second packer is 11.17mm, 23.78mm , or 36.46 mm. The theory basis is provided for the decision of reasonable distance between two packers.

With respect to the conventional coupling thread, the coiled tubing had the advantages of without screwing on and screwing off in the lifting pipe string. It was widespread used in the drilling and repairing well. According to the actual state of the coiled tubing, the mechanical models on the ground and in the wellbore were established in this article. The were able to simulate the contact state of the coiled tubing through the drum, the guide frame, the injector head and in the wellbore. The curves of the axial force that through the rollers, guide frame, injection head and wellhead was obtained with the changes of the depth.

Columns are prone to sinusoidal buckling and repeated instability on the effect of drilling pressure and fluid pressure during drilling operation. The resulted large area of random contact to borehole wall would affect the drilling efficiency. It made the backreaming and loading hard and the drilling pressure low. Using energy method, taking flexural deformation energy and external potential energy of strings, hole section (slant hole, bending hole, level hole) and annular clearance etc. into consideration, derived the counting function of force that sinusoidal buckling occurred on coiled tubing when it contact with the wellbore, establishing the mechanical analysis method of calculating for sinusoidal buckling of slim lined construction roof bolt and string borehole. It proves an effective method for the applying of coiled tubing drilling pressure and the optimization of process parameters.

The article carries on the question of the failure of the transmittal belt of the small supple-like pumping unit in Daqing oil field. But the fatigue life is not forecasted accurately. According to the characteristic that the pumping unit stands alternating dynamic load and the contact between transmittal belt and band wheel, this article established the finite element model of transmittal belt using ANSYS software. The model considered the biggest and the smallest stresses in the belt during a circle .It also established four element models in four special conditions and calculated respectively the stress in each time .Taking all the stress into considered and uniting the fatigue curve, it completed the fatigue life analysis.Through the comparative analysis with the fatigue life that the working site statisticsed in all kinds of behaviours, its error is smaller than 5%. It explains that this model is able to forecast the transmittal belt’s fatigue life more accurately. So it provides the reliable basis for making and choosing the transmittal belt.