Complementary hydro-mechanical coupled finite/discrete element and microseismic modelling to predict hydraulic fracture propagation in tight shale reservoirs
Complementary hydro-mechanical coupled finite/discrete element and microseismic modelling to predict hydraulic fracture propagation in tight shale reservoirs
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DOI：
10.1007/s40571-015-0081-4
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发表时间：
2016-04
影响因子：
3.3
通讯作者：
M. Profit;M. Dutko;Jianguo Yu;S. Cole;D. Angus;A. Baird
中科院分区：
文献类型：
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作者：
M. Profit;M. Dutko;Jianguo Yu;S. Cole;D. Angus;A. Baird
本文提出了一种预测致密页岩储层水力裂缝扩展的新方法。许多水力裂缝建模方案都假定裂缝方向在问题域离散化中是预先播种的。这是一个严重的限制，因为储层通常含有大量预先存在的裂缝，这些裂缝会严重影响裂缝的扩展方向。为了克服这些缺点，提出了一种新的裂缝建模处理方法，其中引入离散裂缝面是基于新的和动态更新的几何实体，而不是基于底层空间离散化的拓扑结构。水力压裂是一个固有的耦合工程问题，当储层岩石的应力状态达到某一破坏准则时，流体流动与压裂之间存在相互作用。这项工作采用了交错的流体-机械耦合有限/离散单元方法，以捕捉流体压力与裂缝生长之间的关键相互作用。在现场实践中，裂缝的生长对设计工程师来说是隐藏的，微震活动经常被用来推断水力裂缝的长度和方向。微震输出也可以通过地质力学模型中有效应力的变化来计算，并与现场微震活动进行比较。通过水力压裂数值算例对该新技术进行了说明。
This paper presents a novel approach to predict the propagation of hydraulic fractures in tight shale reservoirs. Many hydraulic fracture modelling schemes assume that the fracture direction is pre-seeded in the problem domain discretisation. This is a severe limitation as the reservoir often contains large numbers of pre-existing fractures that strongly influence the direction of the propagating fracture. To circumvent these shortcomings, a new fracture modelling treatment is proposed where the introduction of discrete fracture surfaces is based on new and dynamically updated geometrical entities rather than the topology of the underlying spatial discretisation. Hydraulic fracturing is an inherently coupled engineering problem with interactions between fluid flow and fracturing when the stress state of the reservoir rock attains a failure criterion. This work follows a staggered hydro-mechanical coupled finite/discrete element approach to capture the key interplay between fluid pressure and fracture growth. In field practice, the fracture growth is hidden from the design engineer and microseismicity is often used to infer hydraulic fracture lengths and directions. Microseismic output can also be computed from changes of the effective stress in the geomechanical model and compared against field microseismicity. A number of hydraulic fracture numerical examples are presented to illustrate the new technology.