Erosion is one of the most common forms of material failure and equipment damage in gas transmission pipelines. Shale gas fields use hydraulic fracturing whereby solid particles are often carried in the gas flow, and the pipeline is in a high-pressure state, which is more likely to cause erosion. The prediction of particle erosion regulation in gas-solid two-phase flow is an effective means to ensure the safe operation of shale gas fields. In this paper, an integrated CFD-DPM model is established to investigate the erosion of 90° elbow in a shale gas field under gas-solid two-phase flow, employing the realizable k-ε turbulence model, discrete phase model, and erosion rate prediction model. The reliability of the proposed numerical models is verified by comparing the predicted data with the experimental data. Moreover, the effects of six important factors on maximum erosion rate are analyzed, including gas velocity, mass flow rate of sand particles, particle diameter, shape coefficient of sand particles, pipeline diameter, elbow radius of curvature. Specifically, the results indicate that the gas velocity, mass flow rate and shape coefficient of sand particles are positively correlated with the maximum erosion rate, while the pipe diameter and the elbow radius of curvature are negatively correlated with the maximum erosion rate. A new correlation was developed, which included four dimensionless groups, namely Reynolds number, diameter ratio, density ratio and particle number. The correlation can be used to predict maximum corrosion rate of elbows. This work can provide data reference and theoretical basis for mitigating the erosion rate of pipelines and managing the integrity of gas pipelines.

The adsorption of coalbed methane alters the pore structure of reservoirs, subsequently affecting the coal seam’s gas adsorption capacity. However, traditional gas adsorption models often neglect this crucial aspect. In this article, we introduce a fractal capillary bundle model that accounts for the expansion of coal seam adsorption. We utilize curvature fractal dimension and capillary fractal dimension to characterize the complexity of the coal seam’s pore structure. By incorporating the concept of fictitious stress, we have described the relationship between gas adsorption, matrix porosity, and permeability changes. We have developed a model that describes the changes in matrix porosity and permeability during the gas adsorption process. After fitting this model to experimental data, it demonstrated high accuracy in predictions. Furthermore, our investigation into how factors such as curvature fractal dimension, capillary fractal dimension, and fictitious stress influence gas adsorption capacity reveals several key findings. Firstly, the specific surface area within the pore structure of coal seams is the primary factor controlling gas adsorption capacity. Secondly, the virtual stress generated during the gas adsorption process alters the coal seam’s maximum gas adsorption capacity, a factor that cannot be overlooked. Lastly, we found that gas adsorption primarily affects the gas migration process, while under high-pressure conditions, gas desorption does not cause significant changes in the matrix porosity and permeability.

Erosion caused by solid particles in a pipeline is one of the main problems endangering the safety production of the oil and gas industry, which may lead the equipment to malfunction or even fail. However, most of the previous studies focused on the standard elbow, and the erosion law of right-angle elbow and blind tee is rarely reported in the literature. This work aims to investigate the erosion law of different pipeline structures including 90° elbow, right-angle pipe, and tee pipe based on the production characteristics and engineering parameters of the gas field. An integrated CFD-DPM method is established including a realizable k-ε turbulence model, discrete phase model, and erosion rate prediction model. The accuracy of the model is evaluated by a series of experimental data of flow conditions of our previous work. Further, the erosion rate, pressure distributions, and particle trajectories in 90° elbow, right-angle pipe, and tee pipe under different flow velocities, particle mass flow rate, pipe diameter are investigated by applying the presented model. The results show that the blind tee has the most obvious growth rate, and the most serious erosion is located in the blind end of the pipe wall. The maximum erosion rate of the 1.5D is greater than that of the 3D elbow as a whole, and the 1.5D elbow is more concentrated in the serious erosion area. Furthermore, the erosion rate of the bend weld is much greater than that of the straight pipe weld. This study can provide a basis for the selection of different structural pipe fittings, thereby reducing the pipeline erosion rate and improving the integrity of the management of gas pipelines.

The potential technical and economic advantages and flexible operability of modular equipment make it increasing widely used in gas field production and development. In addition to considering the manufacturing process, the selection and serialization of modular equipment should be made according to the productivity prediction of a gas well, so as to meet the field demand to the greatest extent and enhance the flexibility of gathering and transportation system. This article proposes a method to determine the use planning of modular equipment in shale gas field. Considering the processing capacity, processing cost, floor area, construction cost of modular equipment, and the changes of market supply and demand, an optimization model is established. On the basis of the abovementioned model, the method of serialization of modular equipment is proposed. The effectiveness of the model is verified by an actual case study. It is proved that the model can optimize the layout of modular equipment, make the modular equipment run efficiently and economically, reduce costs, and increase efficiency. This study provides a reference for optimizing the equipment management strategy and promoting green production practice of shale gas production.

Performing stress‐sensitivity evaluation on a high‐temperature and high‐pressure gas reservoir is essential for correctly understanding the characteristics of physical property changes and reasonably designing the development scheme of a reservoir under stratum conditions. By focusing on six core samples with different physical properties in a gas field in the Yingqiong Basin, stress‐sensitivity experiments have been conducted along with mercury intrusion porosimetry and X‐ray diffraction measurements to study the relationship among porosity, permeability, and effective stress at a temperature of 140°C and effective stress ranging from 2 MPa to 70 MPa. Our results showed that the stress‐sensitivity curve characterized by three‐stage segmentation is primarily affected by average pore radius and mineral composition but has no direct relation with porosity and permeability. Meanwhile, the stress sensitivity of permeability is mainly related to the average pore throat radius and mineral composition of core specimen. The smaller the pore throat radius and the higher the clay content, the stronger the stress sensitivity of permeability. Under high‐temperature and high‐pressure conditions, the stress sensitivities of permeability and porosity can be characterized by power functions although the stress sensitivity of permeability is about 2–11 times higher than that of porosity.