摘要
The hydraulic fracturing technology has been widely utilized to extract tight resources.Hydraulic frac-turing involves rock failures,complex fracture generation,proppant transport and fracture closure.All these behaviors affect the productivity of fractured wells.In this work,the advances and challenges in hydraulic fracturing development of tight reservoirs are summarized from following aspects:the hy-draulic fracture propagation,the proppant transport and distribution in hydraulic fractures,the calcu-lation of hydraulic fracture conductivity,and productivity and/or pressure analysis model of multi-stages fractured horizontal wells.Current fracture propagation simulation methods generate only limited propagation paths and cannot truly reflect the complexity of the propagation.The current proppant migration and distribution research is mainly focused on indoor experimental studies of proppant migration in a single fracture or branched fracture,and simulation studies on proppant migration and distribution in a small-scale single slab fracture.Whereas fractures formed after hydraulic fracturing in tight reservoirs are generally complicated.There is a lack of models for calculating complex fracture conductivity that take into consideration the effect of proppant placement and proppant distribution in fractures,fracture surface roughness and dissolution,diffusion,deposition,elastic embedding,and creep caused by stress.The productivity models of fractured horizontal wells are mostly conducted based on the original reservoir fluid saturation and pressure distribution.Most of the studies are focused only on one aspect of the fracturing process.Predications of well performance after fracturing based on these studies are often inconsistent with actual field data.The paper also discusses the future research di-rections of fracturing in tight reservoirs and the results may be used to promote the development of tight reservoirs.
基金
This work was supported by the National Natural Science Foun-dation of China(No.51974343)
the Independent Innovation Scien-tific Research Project(science and engineering)of China University of Petroleum(East China)(No.20CX06089A)
Qingdao Post-doctoral Applied Research Project(No.qdyy20200084).
