非常规油气作为我国油气资源中的重要接替能源,其高效开发对于保障国家能源安全具有重要意义.采用水平井分段多簇压裂技术,并优化压裂段内多簇压裂参数,对最大化非常规储层产能至关重要.明确裂缝扩展规律,量化裂缝形态与产能之间的关系,是水平井段内多簇压裂方案优化的关键.本文基于相场方法仿真段内多簇裂缝竞争扩展形态,通过集成的裂缝形态识别技术,进而构建二维等效裂缝模型,用以表征压裂渗流通道,并提取改造后等效物性参数,分别作为几何与物性输入参数传递至裂隙流模型,实现两种方法的自动耦合与传递,进而对不同压裂工况下的产能进行定量评估,最终实现裂缝扩展—渗流一体化模拟.通过室内物理模拟实验与现场压裂施工数据对比分析,验证了双重模型耦合的准确性与可行性.在此基础上,本文进一步研究了基于该方法的段内簇数和簇间距对裂缝形态及产能响应的影响规律.研究结果表明:当簇间距由 15 m增加至25 m时,裂缝发生偏转的位置后移,裂缝尖端的偏转角度由 30°降低至 24°,裂缝周围压力梯度降低,流体驱动力减弱,裂缝之间的流体干扰效应显著减小,这一变化导致日产峰值与稳产水平有所下降,日产油、累计产油量降幅分别为 35.88%和 35.89%;当段内簇数由 3 簇增加至 5 簇时,外侧裂缝尖端偏转角度由 30°增加至 34°,诱导应力场控制面积由 36.74%增加至 42.46%,裂缝周围压力梯度增强,流体驱动力增大,原油的动用程度得到显著提升,致使日产峰值与稳产水平相应提高,日产量、累计产油量增幅分别为 40.49%和 45.467%.因此,优化簇间距与簇数,可以兼顾控制裂缝干扰程度和提高单井产能,从而提高水平井段内多簇压裂改造效果.

Unconventional oil and gas resources serve as vital replacement energy in China's hydrocarbon portfolio,and their efficient development is of great significance for safeguarding national energy security.The implementation of staged multi-clus-ter hydraulic fracturing in horizontal wells,along with the optimization of intra-stage cluster design parameters,is critical to maximizing the production potential of unconventional reservoirs.Clarifying fracture propagation mechanisms and quantifying the relationship between fracture geometry and well productivity is key to optimize intra-stage multi-cluster fracturing strategies.In this study,a phase-field method is employed to simulate the competitive propagation morphology of multiple fractures within a fracturing stage.A fracture morphology identification technique is integrated to construct a two-dimensional equivalent fracture model,which can characterize the stimulated flow pathways.Equivalent physical parameters after stimulation are extracted and transferred-together with geometric descriptors-as input for a discrete fracture flow model.This enables automatic coupling and data transfer between the geometric and flow models,thereby facilitating quantitative evaluation of production performance under different fracturing scenarios and ultimately achieving fully coupled fracture propagation-fluid flow simulation.The accuracy and feasibility of the dual-model coupling method are verified through comparison with laboratory-scale physical simulation experiments and field fracturing data.On this basis,the effects of intra-stage cluster number and cluster spacing on fracture morphology and production response are further investigated.The results show that,as the cluster spacing increases from 15 m to 25 m,the fracture deflection point shifts farther from the wellbore,and the tip deflection angle decreases from 30° to 24°.Meanwhile,the pressure gradient around the fracture tip is reduced,weakening the fluid driving force and significantly diminishing inter-fracture fluid interference.This change leads to a decline in peak daily oil production and stabilized production rate,with daily and cumulative oil output decreasing by 35.88%and 35.89%,respectively.In contrast,when the number of clusters per stage increases from 3 to 5,the deflection angle at the tip of the outer fractures increases from 30° to 34°,while the coverage of the induced stress field expands from 36.74%to 42.46%.This results in a higher pressure gradient surrounding the fractures,enhancing the fluid driving force and significantly improving oil mobilization.Consequently,peak daily and cumulative oil production increased by 40.49%and 45.467%,respectively.Therefore,optimizing the intra-stage cluster spacing and cluster number can effectively balance the degree of fracture interference and enhance single-well productivity,thereby improving the overall effectiveness of staged multi-cluster hydraulic fracturing in horizontal wells.