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In this paper, the dynamic response analysis of long-span continuous bridge under earthquake and train load was simultaneously performed. In order to clearly reveal the mechanism of vibration coupling between vehicles and highway long-span continuous bridge, a numerical model including soil foundation, vehicle and bridge under inclined seismic wave was established utilizing finite element software. The dynamic response of the bridge with different wave incident angles and different train speeds was numerically analyzed. The results show that the wave incident angles have a significant effect on the dynamic response of the bridge, and with the increasing of the wave incident angle, the vertical displacement and velocity as well as the acceleration of mid-span constantly increase. While the dynamic response of the bridge does not increase always with the increasing of train speed, however, at a certain train speed, the dynamic response will reach the maximum. With the increasing of the train speed, the vertical displacements of mid-span points increase while the moments at mid-span reduce significantly when the soil–structure dynamic interaction was considered. The results can provide significant references to ensure the train safe running on the bridges under the earthquake.

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Huge oil reserves are located in ultra-low permeability reservoirs in the Ordos basin in China. There are three key characteristics associated with these reservoirs: low reservoir quality (10 to 13% in porosity), low reservoir permeability (0.3 to 2.0 mD), and low reservoir pressures (pressure gradients of 0.0075 to 0.009 MPa/m). The Chang 6 formation in the Huaqing field is classified as ultra-low permeability reservoirs. Water injection to maintain reservoir pressure is important to develop the Chang 6 formation in horizontal wells. Fracturing design optimization is the key to improving well production and reservoir development effectiveness. Reservoir simulation studies were performed to determine optimal well pattern and well spacing. Fracture modeling studies were also conducted to determine the optimal number of fracture stages in each horizontal well and to optimize fracture design for each stage in order to take into consideration the relative location between each individual stage and nearby injection wells, with the objective of postponing water breakthrough and reducing water production. Completion, stimulation and cumulative production data from 24 horizontal wells were compiled and compared with 121 vertical wells under similar reservoir conditions. Oil production from horizontal wells was increased by four folds on average in comparison with vertical well completion.

Loads subjected by the boom system on the concrete pump are so complex, that fatigue cracks or fatigue fractures appear, which may lead to loss of property and casualty. However, when the concrete pump is functioning in safe condition, the damage of the boom system is reduced, thereby preventing the accidents. In order to select safe working conditions, a boom system of 37m concrete pump as research object should be adopted. The finite element analysis is carried out on the boom system based on MSC. Patran and Nastran, with regularly varying degrees, and changing trends of the maximum stresses subjected by booms with the change of degrees of booms, attained a safe condition of the boom system. Finally, taking the four kinds of typical foundation casting working conditions as example, the feasibility of using this condition to determine the safe working condition has been verified.

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Water flooding development of Chang 6 ultra-low-permeability reservoirs in Ansai lasted for more than 30 years; the front of the water drive has swept the reservoir high permeability zone. As a result, a large amount of residual oil stayed in the reservoir longitudinal low-permeability area. To recover the remaining oil in the low-permeability layers, the fixed-plane perforation fracturing technology is proposed, i.e., using fixed-plane perforation to form a sector stress concentration surface perpendicular to the axis of the wellbore, which makes hydraulic fracture expand radially along the wellbore and control the longitudinal direction of the fracture. Based on the study of residual oil distribution and variation of rock mechanics parameters under long-term injection and production conditions, we simulated and analyzed the effect of fracture initiation under different perforation phases. The optimum perforation phase angle was selected according to the size of the fracture fusion area. According to the fracture simulation under the condition of weak stress difference, the parameters of fracturing operation were optimized with controlling fracture height. A 2-fold increase in ultra-low-permeability reservoir production was achieved by fixed-plane perforation fracturing compared with traditional fracturing technology according to the production data of 78 wells. In this paper, we propose a fixed-plane injection fracturing technique to address the problem of tapping the remaining oil in the longitudinal low-permeability section of the reservoir, which can provide support for tapping the remaining oil in the low-permeability section of the extra-low-permeability reservoir.