Diagnosis of fracturing interference and effect evaluation in horizontal well groups

To address the current challenges of diagnosing fracturing interference types and the lack of an evaluation system for interference effectiveness in horizontal well groups in unconventional reservoirs, this study proposes a method for diagnosing and evaluating fracturing interference. Based on the principles of unconventional complex fracture modeling, the fracture propagation model is established. By simulating four typical fracture interference patterns—non-propagating fracture pattern, main fracture propagation pattern, branch fracture propagation pattern, and natural fracture connectivity pattern—the spatial distribution patterns of inter-well fractures are forward-modeled, and diagnostic criteria for typical fracturing interference patterns in horizontal well groups were developed. Based on the principles of pressure falloff well-test interpretation and considering the characteristics of inter-well fracturing interference, the interference well-test evaluation model was constructed. Inverse calculation of fracture parameters was carried out to analyze fracture propped effectiveness under different interference patterns and to clarify the impact of fracturing interference on the effectiveness of horizontal well groups. The proposed method was applied to a typical fracturing interference horizontal well groups in the Daniudi Gas Field, Ordos Basin, China. And its validity was confirmed by comparison with microseismic monitoring results. The study demonstrates that: The impact of fracturing interference on the stimulation effectiveness of horizontal well groups follows the order: main fracture propagation pattern > branch fracture propagation pattern > natural fracture connectivity pattern. Specifically, the main and branch fracture propagation patterns exert negative effects, reducing propped fracture volume by 7.2% and 4.6%, respectively. The natural fracture connectivity pattern has a positive effect, increasing propped fracture volume by 3.5%.