Enhancing total fracture surface area in naturally fractured unconventional reservoirs via model predictive control
Enhancing total fracture surface area in naturally fractured unconventional reservoirs via model predictive control
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DOI：
10.1016/j.petrol.2019.106525
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发表时间：
2020
影响因子：
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通讯作者：
Prashanth Siddhamshetty;Parth Bhandakkar;J. Kwon
中科院分区：
文献类型：
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作者：
Prashanth Siddhamshetty;Parth Bhandakkar;J. Kwon
在天然裂缝性非常规油气藏中，天然存在的裂缝将与水力裂缝相互作用，并使裂缝扩展转向。由于复杂的裂缝生长，在天然裂缝性非常规储层中的水力压裂操作的最终目标应该从实现期望的裂缝几何形状改变为对于给定的压裂资源最大化总裂缝表面积（TFSA），因为它将允许更多的泄油面积可用于石油回收。不幸的是，对于天然裂缝性非常规储层中的给定压裂资源，没有这样的技术可用于制定泵送计划以最大化TFSA。基于此，在这项工作中，我们将开发一个新的基于模型的抽水时间表，利用最近开发的非常规的复杂裂缝扩展模型称为红树林作为我们的虚拟实验描述复杂的裂缝网络，通过考虑水力裂缝和天然裂缝之间的相互作用。首先，使用从红树林的仿真数据，一个降阶模型（ROM），然后使用它来开发一个卡尔曼滤波器，利用现有的测量来估计不可测量的ROM状态。然后，我们提出了一个基于模型的反馈控制系统，以确定压裂液泵送时间表，最大限度地提高TFSA，这将导致从天然裂缝非常规油藏提高石油生产率。我们证明，通过使用所提出的控制方案，TFSA可以大大提高，这将导致石油生产率大于现有的泵抽时间表，而不考虑天然裂缝。
In naturally fractured unconventional reservoirs, naturally present fractures will interact with hydraulic fractures, and divert fracture propagation. Because of complex fracture growth, the ultimate goal of hydraulic fracturing operation in naturally fractured unconventional reservoirs should be changed from achieving the desired fracture geometry to maximizing the total fracture surface area (TFSA) for given fracturing resources, as it will allow more drainage area available for oil recovery. Unfortunately, there are no such techniques available to develop pumping schedules to maximize TFSA for given fracturing resources in naturally fractured unconventional reservoirs. Motivated by this, in this work, we will develop a new model-based pumping schedule by utilizing a recently developed unconventional complex fracture propagation model called Mangrove as our virtual experiment describing complex fracture networks by accounting for the interaction between hydraulic fractures and natural fractures. Initially, using the simulation data from Mangrove, a reduced-order model (ROM) is constructed, which is then used to develop a Kalman filter utilizing the available measurement to estimate the unmeasurable ROM states. Then, we propose a model-based feedback control system to determine the fracturing fluid pumping schedule that maximizes TFSA, which will lead to an enhanced oil production rate from naturally fractured unconventional reservoirs. We demonstrate that by using the proposed control scheme, TFSA can be greatly enhanced which will lead to an oil production rate greater than those of existing pumping schedules which were developed without considering natural fractures.