Bowland Shale well placement strategy - Part 2: Fracture simulations using a 3D geomechanical model and implications for stratigraphic and spatial horizontal well locations
Bowland Shale well placement strategy - Part 2: Fracture simulations using a 3D geomechanical model and implications for stratigraphic and spatial horizontal well locations
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Bowland 页岩井布井策略 - 第 2 部分：使用 3D 地质力学模型进行裂缝模拟以及对地层和空间水平井位置的影响
DOI：
10.1016/j.engeos.2022.03.004
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发表时间：
2022
影响因子：
--
通讯作者：
De Jonge-Anderson I
中科院分区：
文献类型：
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作者：
De Jonge-Anderson I
水力压裂建模是页岩储层布井策略的关键组成部分，因为它提供了受刺激裂缝的典型长度和高度以及这些裂缝传播的应力环境变化的指示。然而，页岩的应力和地质力学性质的空间和地层变化使得精确建模成为一项具有挑战性的任务。对于英国Bowland页岩，可以使用针对多个地层间隔的堆叠水平威尔斯井，以避免地质复杂区域中的大偏移断层。然而，目前尚不清楚这些间隔如何对水力压裂作出反应，并且预测水力压裂的高度和长度是必要的，以便评估垂直裂缝干扰跨着陆区或向主要断层传播的可能性。在前者的情况下，高有效应力的间隔可能是将裂缝包含在其期望目标内的关键。使用平面水力压裂模拟器和包含倾斜地层的三维地质力学模型，通过一系列使用Preese Hall-1井和水平伪井的建模练习，对Bowland页岩中水力压裂几何形状的预测问题进行了评估。当预定义的着陆区为目标时，模拟距离油井约1公里的窄而长的横向裂缝。当模拟设计模拟沿水平伪井沿着以12 m间隔布置的射孔簇时，应力阴影的影响是尖锐的，并导致不规则的裂缝几何形状。此外，高有效应力区间有效地起到了垂直水力压裂扩展的屏障的作用，增强了Bowland页岩使用叠层生产的可行性。然后，利用模拟结果讨论了在绘制的Preese Hall-1井周围100 km 2区域内可能的水平威尔斯井位置，在该区域内最多可设置13个位置，水平井长度约为1.5 km。最后，通过借鉴Bowland页岩的成熟类比，估计如果从一个地点生产三个地层间隔，则该地区13个地点可生产高达195 Bcf的天然气。
Hydraulic fracture modelling is a key component of a shale reservoir well placement strategy as it provides an indication of the typical lengths and heights of stimulated fractures and of the changes to the stress environment in which these are propagating. However, spatial and stratigraphic variations in the stress and geomechanical properties of shales make accurate modelling a challenging task. For the UK Bowland Shale, stacked horizontal wells targeting multiple stratigraphic intervals could be used to avoid large offset faults in a geologically complex area. However, it is not known how these intervals may respond to hydraulic fracturing and predicting the height and length of hydraulic fractures is necessary in order to assess the likelihood of vertical fracture interference across landing zones or propagation towards major faults. In the case of the former, intervals of high effective stress may be key to containing fractures within their desired target. Using a planar hydraulic fracture simulator, and a 3D geomechanical model incorporating dipping stratigraphy, the issue of predicting hydraulic fracture geometry in the Bowland Shale was assessed through a series of modelling exercises using well Preese Hall-1 and horizontal pseudo-wells. When pre-defined landing zones were targeted, narrow and long transverse fractures around 1 km from the well were simulated. When the simulation design mimicked perforation clusters placed at 12 m intervals along horizontal pseudo-wells, the effects of stress shadowing were acute and resulted in irregular fracture geometries. Furthermore, high effective stress intervals performed efficiently as barriers to vertical hydraulic fracture propagation, reinforcing the feasibility of using stacked production for the Bowland Shale. The modelling results were then used to discuss the possible placement of horizontal wells in a mapped, 100 km2region around well Preese Hall-1, where up to 13 sites could be positioned, with a horizontal well length of around 1.5 km. Finally, by drawing on a well-established analogue for the Bowland Shale, it was estimated that up to 195 Bcf of gas could be produced from the 13 locations in the area if three stratigraphic intervals are produced from one location.