Analysis of Development Performance and Influencing Factors of Chang 7 Shale-Oil Horizontal Wells in the Longdong Area, Ordos Basin

This study investigated 49 hydraulically fractured horizontal wells in the Chang 7 Member of the Ordos Basin to establish a life-cycle development-performance evaluation framework for shale-oil reservoirs. To improve cross-well comparability, production histories were aligned at the end of flowback, and development performance was characterized using initial productivity, cumulative production, and stage-specific decline indicators. The integrated evaluation framework combined Criteria Importance Through Intercriteria Correlation (CRITIC) weighting, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and weighted K-means clustering. Geological and engineering parameters, pressure-transient interpretations, and production-profile data were further integrated to investigate the controlling factors of different production-performance types. The results show that the 49 wells were classified into three production-performance types: high-cumulative-production/stable wells, moderate-to-high-initial-rate/rapid-decline wells, and low-rate/slow-decline wells, comprising 18, 11, and 20 wells, respectively. The three types exhibited distinct production trajectories, with Type II wells characterized by rapid early decline despite relatively high initial productivity, whereas Type III wells showed persistent low productivity. Individual geological and engineering parameters did not show significant differences among well types, indicating that development performance results from the combined effects of reservoir penetration, fracturing effectiveness, pressure-maintenance capacity, and horizontal-section utilization. Pressure-transient analysis further revealed different constraints on productivity evolution among well types, while production-profile data demonstrated substantial heterogeneity in horizontal-section contribution. The proposed framework integrates standardized production-time alignment with multiscale production-performance indicators and dynamic reservoir characterization, providing a practical approach for differentiated management of shale-oil horizontal wells. The methodology may also provide a reference for evaluating similar lacustrine shale-oil reservoirs, subject to validation using independent datasets.