The emergence of large language models（LLM） with characteristics of general artificial intelligence has ushered in a milestone technological revolution across industries，offering new opportunities for the intelligent transformation of petroleum engineering. This paper explores the application prospect，challenges，and development recommendations for LLM，represented by DeepSeek，in petroleum engineering. First，the fundamental concepts and technical features of LLM are introduced. Subsequently，potential application scenarios in petroleum engineering are examined，including user interaction and Q&A systems，data governance and information integration，data analysis and decision support，information parsing and intelligent assistance，and environmental monitoring and safety management. Concurrently，limitations and challenges in applying LLM to petroleum engineering are identified，such as insufficient knowledge updating capabilities，difficulties in comprehending domain-specific expertise，limited innovation in scientific research，and high training costs. Finally，recommendations and future directions for leveraging LLM in petroleum engineering are proposed，including developing specialized LLMs tailored for petroleum engineering，constructing petroleum-domain databases and information extraction frameworks，integrating internet-enabled search and real-time updating functionalities，and advancing image processing and video generation technologies. This study systematically outlines an implementation framework for LLM in petroleum engineering，providing theoretical guidance and practical references for the industry’s intelligent evolution.

Previously，the carbonate reservoir of Majiagou Formation in Yan'an Gas Field adopted traditional acid fracturing treatments，which ended up with a limited acid-affected range and low post-frac well production. This necessitates the optimization of the acid fracturing practice. The reservoir outcrop samples of the Fifth Member of Majiagou Formation were collected for experiments，and the etched-fracture conductivity meter and 3D laser scanning technology were used for acid etching experiments and fracture conductivity measurement in the cases of supercritical CO₂ （SC-CO₂） prepad acid fracturing and conventional acid fracturing. The effects of  prepad SC-CO₂ and SC-CO₂ soaking time on etched fracture morphology and conductivity were investigated. The results demonstrate that acid fracturing with prepad SC-CO₂，compared with the conventional method，opens natural fractures，enhances the penetration and diffusion of acid solutions into micro-fractures，and thereby improves acidizing effectiveness. After 12 h and 24 h of SC-CO₂ Soaking，the dominant acid etching pattern resembles grooves，with no significant changes in overall etching severity or types.The 48 h soaking ething is associated with the predominant bridge-pier-like etching marks，while the uniform etching is found dominant after 72 h soaking. The difference of fracture conductivity between conventional acid fracturing and SC-CO₂ prepad acid fracturing is minor under the closure pressure below 30 MPa，and yet，a substantial disparity emerges beyond this threshold. The fracture conductivity of SC-CO₂ prepad acid fracturing consistently exceeds that of conventional acid fracturing across the closure pressure range of the experiments. In cases of low closure pressure，the soaking duration is positively correlated with the etched fracture conductivity，whereas excessively prolonged soaking periods under high closure pressure can suppress fracture conductivity. Therefore，48 h well shut-in is recommended. The findings of this research provide theoretical support for the scheme development of compound acid fracturing in carbonate reservoirs.

Multi-cluster perforation staged fracturing of horizontal well has become one of the key technologies for completion and stimulation in unconventional oil and gas reservoirs. However，the fractures of the central perforation clusters in each fracturing stage are significant affected by stress interference from the fractures of heel and toe clusters，leading to substantial propagation resistance of the central cluster fractures. This is a major cause of the unbalanced propagation of multi-cluster fractures. This study optimized the design of non-uniform perforation distribution pattern between clusters to regulate the perforation parameters，balance the fluid distribution among clusters，mitigate the stress interference between fractures，and promote the balanced propagation of fractures. Therefore，a multi-stage，multi-cluster fracture propagation model that accounts for stress superposition between stages/clusters was established. The model was used to compare and analyze the fracture propagation patterns and mechanisms of spindle-shaped，sloped and uniform perforating patterns. The difference in fracture length and height propagation morphology was utilized to assess the equilibrium of fracture propagation. The perforation distribution pattern was optimized，and an orthogonal test was designed to refine the parameters of non-uniform perforation distribution pattern. The findings indicate that under typical shale oil reservoir conditions，the spindle-shaped perforation pattern achieves the best fracture propagation equilibrium，followed by uniform pattern and then the sloped pattern. The mechanism is that，with the spindle-shaped perforation pattern，the clusters at both ends have a perforation friction 1.4~16.7 times greater than that of the central clusters，reducing the stress interference from the heel and toe fractures on the central-cluster fractures. This results in an increased fluid inflow distribution in the central clusters，enhancing the fracture propagation equilibrium by 17.2 % compared to the uniform pattern. Conversely，the sloped perforation pattern，with over 35% of the holes concentrated at the toe cluster and accounting for 49.3 % of the fluid inflow，exerts a significant squeezing effect on the central cluster fractures，which is counterproductive to achieving a balanced fracture propagation. The optimization of the spindle-shaped perforation parameters reveals that an fracture propagation equilibrium is achieved with a total of 49 holes，a perforation diameter of 10 mm，and an end-cluster perforation proportion of 24.5%. The research results are expected to offer an effective approach for the design of non-uniform perforation in multi-cluster fracturing for unconventional oil and gas reservoirs. 

The MH gas reservoir in Xinjiang has been through many years of depletion recovery. In order to meet the seasonal peak demand，the depleted gas reservoir is being reconstructed into an underground gas storage （UGS）. Due to alternating gas injection-production，the reservoir is prone to sand production during the injection-production process，which impacts on the operation and stability of the UGS. In order to clarify the mechanism of sand production under the alternating injection-production mode of the UGS，this paper used the reservoir cores to carry out the physical property，rock mechanics and alternating flooding experiments. The main composition，cementation and mechanical properties of the cores were analyzed，and the effects of drawdown pressure，confining pressure and alternating injection-production process on sand production were investigated. The experiment results show that the reservoir skeleton presents dissolution sericitization，high kaolinite content in clay minerals，weak mechanical strength properties，and has the risks of sand production under the UGS operating conditions. During cyclic injection and production，an increase in drawdown pressure promotes sand production. When the drawdown pressure exceeds 6 MPa，the rock reaches a critical state of sand production. Increasing confining pressure leads to premature sand production. Moreover，as the confining pressure rises，sand production first increases and then decreases. The extrusion of pore channels is the main driver for the decrease in sand production. In comparison to conventional gas production，the amount of produced sand during the alternating injection-production exhibits a wave-like pattern. The dynamic erosion process and fatigue failure of cementation，induced by multiple rounds of alternating injection-production，are the main contributors to exaggerate sand production from the UGS.

Enhancing the rate of penetration （ROP） is crucial for optimizing the efficiency of oil and gas development and deep exploration in China and ensuring national energy security. The percussion rock-breaking drilling technology has been applied in oil fields at home and abroad，resulting in significant improvements in ROP. Further research efforts are expected to address the technical challenges of low drilling footage and limited ROP enhancements encountered during deep exploration of hard rock formations with high temperature and pressure. This paper presents and analyzes the practice and development trends of the drill bit percussion rock-breaking drilling technology assisted by axial percussion，torsional percussion，and axial-torsional coupled percussion. It illustrates that the percussion-assisted drill bit rock-breaking mechanism is the core of percussion rock-breaking ROP improvement technology. This paper also reviews the scientific advancements made by domestic and overseas research scholars in physical experiments，theoretical modeling，and numerical simulation of percussion-assisted drill bit rock-breaking. In addition，it offers relevant proposals for the development of percussion rock-breaking ROP improvement technology，i.e. advancing research on material structure optimization design，intelligent control，integration of multiple technologies，and optimization of well applications. This is expected to provide valuable insights for enhancing the drilling efficiency in energy development of our country.