Integrated grounding system (IGS) in china high-speed railway is formed through two long horizontal copper lines named run-through ground wire buried on both sides along the railway, which is also the longest horizontal grounding system in the world through the interconnection of railways. The grounding impedance measurement of IGS of high-speed railway is a novel, important problem to ensure the human and equipment safety. The placement approach of test electrodes for the grounding impedance measurement of the IGS in the roadbed section of high-speed railway was discussed by the simulation calculation and field test results in this study. Numerical analysis and measurement arrangement of IGS grounding impedance based on short-current lead wire was evaluated by analysing the soil structure, the distance of test electrodes and the ratio of measured grounding impedance and true grounding impedance. The test route was suggested that the potential electrode be placed on the opposite side with respect to the current electrode for measuring the grounding impedance. The suitable and convenient test electrode arrangement and the corresponding correction coefficients were obtained. Compared with the computer-aided calculation, the field test maintained acceptable measurement error. Thus, a useful measurement method was proposed for grounding impedance measurement of IGS.

In the process of waterflooding development, high waterflooding PVs will make the fluid percolation in the reservoir more complicated, resulting in lower efficiency of waterflooding. High waterflooding PVs will affect the relative permeability and change the seepage law of oil–water two-phase flow in a high water-cut period. In this study, we performed high waterflooding PVs relative permeability experiments using nine natural cores. The unsteady measurement method is used to test the relative permeability curve. The results show that: (1) the relative permeability is affected by the waterflooding PVs, the recovery efficiency of 2000 waterflooding PVs is 10.72% higher than that of 50 waterflooding PVs on the core scale; (2) it makes water mobility increase sharply, while oil phase flow capacity remains low and decreases at high water cut stage. A new relative permeability characterization method considering high waterflooding PVs is established, which is applied to the numerical simulator. It shows that the remaining oil saturation of the high-permeability belt is higher than the calculation results of the traditional numerical simulator. It means that the injected water does not diffuse much into the low-permeability zone of the formation. The modified simulator is validated with the actual China offshore oilfield model. The numerical saturation of the key section of the passing well is in good agreement with the actual logging interpretation results, and the water cut curve fits better in the whole area. The modified simulator could predict oil production accurately after high waterflooding PVs treatment.

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In order to explore the strengthening effect of the electric field on biodegradable oily soil, through designing 5 gradient electric fields of 0V / m, 50V / m, 100V / m, 200V / m, and 250V / m, the growth and reproduction changes and behavioural dynamics of the electric field on organisms were studied the impact of learning. On this basis, the effects of electric field on the oil-lowering ability of organisms, the accompanying migration characteristics of populations, in situ active replenishment, and the distribution characteristics of nitrate ions and sulphate ions in oily soils were analysed. The results show that when the electric field strength is 100V / m, the biological growth and reproduction rate is the highest, the number of bacteria is the largest, and the loss of nitrogen nutrients is the smallest; the effect on the oil-reducing ability of the oily soil is accordingly coupled effect> single bacteria effect> single electricity effect It shows that the effect of electric field coupling bioremediation technology on oily soil is remarkable.

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