Due to the development characteristics of low‐permeability reservoirs such as weak water absorption, slow development of water injection, and strong pressure sensitivity, the effect of water injection in low‐permeability reservoirs is quite different from that in medium and high‐permeability reservoirs. Therefore, in oilfield development, it is important to study the movement law of the waterflooding front in low‐permeability reservoirs. In this paper, taking the Jilin oilfield as an example, a geological model of Xinmin 23 Block was established for the numerical simulation analysis considering the heterogeneity of low‐permeability reservoirs. In addition, artificial cores were manufactured to conduct the physical experiment of the waterflood front advance of cores with different physical properties under the influence of various factors such as the fracture and the range by the constant‐velocity flooding. Based on the numerical simulation and the physical experiment, the movement law of the waterflood front was analyzed and a basic method for evaluating the waterflooding development in low‐permeability reservoirs was established to provide feasible insights for the waterflooding development in low‐permeability reservoirs. In this paper, numerical simulation and experimental studies were performed on the effect of the waterflooding development of Xinmin 23 Block in the Jilin oilfield. The evaluation results obtained were consistent with the actual oil production providing a theoretical basis for judging the accurate advance time from the waterflood front to the production well in actual oil production.

The displacement of two-phase fluids within porous media is a critical process in various engineering and industrial fields. However, the inherent instability of the fluid interface often leads to an irregular morphology of the displacement front, which can impact the efficiency of displacement and limit its application in engineering activities. In this study, the color gradient model based on the lattice Boltzmann method was employed to simulate displacement, with the aim of investigating the dynamic evolution of the displacement front under the combined effects of wettability and injection velocity, specifically during the capillary to viscous fingering transition. The results demonstrate that the impact of wettability on the displacement front morphology increases as the injection velocity decreases. The displacement process with the maximum fingering distribution range and compact morphology is found at the midpoint of the capillary-viscous fingering crossover zone. Furthermore, an in-depth analysis of the phase field evolution and pressure difference changes between the inlet and outlet unveiled the pore-filling mechanisms associated with the unique variation characteristics of the displacement front and the fluid topological structure. These comprehensive pore-scale findings offer theoretical insight supporting the engineering application of the two-phase flow in porous media from multiple perspectives.

Fractal characteristics and the fractal dimension are widely used in the description and characterization of rock fracture networks. They are important tools for coal mining, oil and gas transportation, and other engineering problems. However, due to the complexity of rock fracture networks and the difficulty in directly applying the limit definition of the fractal dimension, the definition and application of the fractal dimension have become hot topics in related projects. In this paper, the traditional fractal calculation methods were reviewed. Using the traditional fractal theory and the head/tail breaks method, a new fractal dimension quantization model was established as a simple method of fractal calculation. This simple method of fractal calculation was used to calculate the fractal dimensions of three rock fracture networks. Through comparison with the box-counting dimension calculation results, it was verified that the model could calculate the fractal dimension of the fracture length of rock fracture networks, as well as quantify it accurately and effectively. In addition, we found a number of similarities between rock fracture networks and urban road traffic networks in GIS. The application of the space syntax metric to rock fracture networks prevents controversy with respect to the definition of the axis and it showed a good effect. Using the space syntax metric as a parameter can better reflect the space relationship of rock fractures than length. Through the calculation of the fractal dimension of the connection value and control value, it was found that the trend of the length fractal dimension was the same as that of the control value, whereas the fractal dimension of the connection value was the opposite. This further verifies the applicability of the space syntax metric in rock fracture networks.

Pipeline-induced vibration phenomena caused by waves and currents during the transportation of oil and natural gas pipelines.Multiphysics coupling calculation considering the influence of fluid flow characteristics in ocean tidal flow environment and mechanical properties of pipeline solid structure on vibration characteristics of S-type pipeline. The analysis of the velocity of the fluid domain and the distribution of the stress distribution of the pipeline, combined with the time history and amplitude of the monitoring point and axis of the pipeline, analyzes the flow-induced vibration response characteristics of the S-transport pipeline. The results show that under the cyclic flow of the two-way tidal basin, the velocity field on the deformation side of the pipeline is lower, the stress at the solid support end is higher than that in the riser region, and the time-displacement of the pipeline fluctuates periodically, and the displacement of the pipeline axis increases sharply in the riser pipe section. It exhibits a normal distribution with extreme values at the center of the pipe segment. The maximum single-pass amplitude in the Verticality basin is twice that of the Parallel basin and the maximum amplitude is about 1D.

Study on Characteristics of Flow-induced Vibration (FIV) Induced by Gas-liquid Two-phase Flow in the Conveying Pipe