Fracture corridors are ubiquitous features formed by closely-spaced sub-parallel fractures, typically occurring in brittle mechanical units. They are important because they can form drains for fluids in hydrocarbon reservoirs and aquifers. Their development is sometimes associated with local structural or sedimentary heterogeneities but other situations exist where their mechanical origin remains obscure. In this paper, we investigate the combined role of contrasts in mechanical properties of consecutive layers and pre-existing fracturing in the formation of fracture corridors in sedimentary rocks, using 2D elastic finite element models.

Our models contain five bonded layers with contrasted elastic properties and two pre-existing open fractures in the central layer. Firstly, we compute stress fields in the models submitted to biaxial compression and compression-extension plane strain loading. We identify favorable stress conditions supporting further fracturing in both situations. Secondly, we investigate fracture clustering mechanisms by means of quasi-static fracture propagations in identified areas of tensile stress. We characterize three situations leading to the development of incipient fracture corridors and discuss their geological implications. Finally, we propose a new conceptual model for the formation of these features in the subsurface, with important consequences for the characterization and modeling of fractured reservoirs.

断裂廊道是普遍存在的特征，是由间距狭窄的次平行裂缝形成的，通常发生在脆性机械单元中。它们之所以重要，是因为它们会形成烃类储层和含水层中流体的排泄口。它们的发育有时与局部结构或沉积异质性有关，但在其他情况下，其机械起源仍然不清楚。在本文中，我们使用二维弹性有限元模型研究了对比在连续层的力学特性和预先存在的裂缝在沉积岩裂缝通道形成中的综合作用。

我们的模型包含五个具有相反弹性特性的粘结层和两个中央层中预先存在的开放裂缝。首先，我们在模型中计算承受双轴压缩和压缩-延伸平面应变载荷的应力场。我们确定了在两种情况下都支持进一步压裂的有利应力条件。其次，我们通过在确定的拉应力区域内准静态裂缝扩展研究裂缝的聚集机制。我们描述了导致初始裂缝通道发展的三种情况，并讨论了它们的地质意义。最后，我们为地下特征的形成提出了新的概念模型，对裂缝性储层的表征和建模具有重要意义。