基于双重介质嵌入式离散裂缝模型的致密油藏产能影响因素

致密油藏具有显著的超低孔超低渗特征,天然微裂缝和水力压裂缝对油藏有效动用至关重要,相关数值模拟研究工作备受关注。研究者们广泛采用嵌入式离散裂缝模型研究致密油藏流动规律,通过修改基质网格渗透率表征天然微裂缝,无法精细刻画微裂缝与基质间流体交换对流动产生的影响。为克服以上不足,考虑基质、复杂天然微裂缝和人工压裂缝间传质机理,建立了致密油藏双重介质嵌入式离散裂缝模型；进一步,对模型进行数值离散处理,编制了相应的模拟器；最后,基于所建立模型研究了天然微裂缝、水平段长度、裂缝间距等多因素对致密油藏产能影响规律。研究结果表明,本文所建立模型产能高于传统EDFM模型；水平段长度越长,产能越大；裂缝间距越小,产能越大；应力敏感对致密油藏生产动态有一定影响,并且随着时间推迟,影响逐渐增强；本文所建模型实现了对基质、复杂天然微裂缝和人工压裂缝间复杂传质机理的精细刻画,相关研究结论可为致密油藏经济高效开发提供借鉴。

Study on capacity of compact reservoir based on dual medium embedded discrete crack model

The tight reservoir has a significant ultra-low hole and ultra-low permeability characteristics, and the natural microcracks and hydraulic fracture are crucial to the effective use of the reservoir, and the relevant numerical simulation research work has attracted much attention. The researchers widely used the embedded discrete fracture model (EDFM) to study the flow law of the dense reservoir. By modifying the matrix grid permeability and characterization of the natural microfracture, it was unable to finely depict the impact of the fluid exchange between the microfracture and the matrix on the flow. In order to overcome the above deficiencies, build a dense oil reservoir dual porosity embeded discrete fracture model (DPEDFM), which considered the mass transfer mechanism between matrix, complex natural microcracks and artificial fracture; Further, the model is numerically discretized and the corresponding simulator is prepared. Finally, based on the model, study the influence of the natural microcracks, horizontal segment length and fracture spacing on the dense reservoir. The results show that the established model capacity is higher than the conventional EDFM model; The longer the horizontal segment length, the greater the production capacity; The smaller the crack spacing, the greater the production capacity; Stress sensitivity has an impact on the production dynamics of tight reservoirs, and it gradually increases over time; The proposed model realizes the fine characterization of the complex mass transfer mechanism between matrix, complex natural microcracks and artificial pressure cracks, and the relevant research conclusions can provide reference for the economic and efficient development of dense reservoir.