Optimal pumping schedule with high-viscosity gel for uniform distribution of proppant in unconventional reservoirs
Optimal pumping schedule with high-viscosity gel for uniform distribution of proppant in unconventional reservoirs
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DOI：
10.1016/j.energy.2020.119231
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发表时间：
2021-02-01
期刊：
影响因子：
9
通讯作者：
Sang-Il Kwon, Joseph
中科院分区：
文献类型：
--
作者：
Pahari, Silabrata;Bhandakkar, Parth;Sang-Il Kwon, Joseph
采用非牛顿高粘度凝胶代替滑溜水作为压裂液，可以提高非常规水力压裂油藏的油气采收率。然而，在文献中，凝胶流变学对裂缝性油藏油气生产的作用还不是很清楚。这种认识的缺乏使得行业很难选择合适的压裂胶粘度参数。考虑到这些局限性，首先，我们开发了一个高保真的非牛顿流体流动模型来模拟裂缝扩展、流体泄漏和凝胶返排过程，以预测水力压裂油藏的产油量。高保真模型的模拟结果显示了裂缝几何形状、地层损伤和凝胶清理过程如何随压裂液流变性而变化。因此，开发的模型可以通过敏感性分析来了解凝胶流变性对油气产量的影响，从而提供一组流变性参数，从而最大限度地提高累积产油量。最后，利用这种最佳的高粘度凝胶，设计一个模型预测控制器，以获得产生目标裂缝几何形状和支撑剂浓度所需的最佳泵送计划。闭环模拟结果表明，所获得的泵送计划成功地实现了所需的裂缝几何形状和泵送结束时的支撑剂浓度，从而实现了非常规油藏的最大产油量。Elsevier Ltd.出版。
Hydrocarbon recovery from a hydraulic-fractured unconventional reservoir can be enhanced by replacing slickwater with non-Newtonian high-viscosity gel as a fracturing fluid. However, in the literature, the role of gel rheology on hydrocarbon production from a fractured reservoir is not very well understood. This lack of understanding makes it difficult for the industry to choose appropriate viscosity parameters of fracturing gels. Motivated by these limitations, first, we have developed a high-fidelity model of non-Newtonian fluid flow to simulate fracture propagation, fluid leak-off, and gel flowback processes to predict the oil production from a hydraulic fractured reservoir. Simulation results of the high-fidelity model show how fracture geometry, formation damage, and gel cleanup process varies with the fracturing fluid rheology. Hence, the developed model is used to understand the effect of gel rheology on hydrocarbon production via a sensitivity analysis, which provides a set of rheological parameters that maximize the cumulative amount of oil production. Finally, utilizing this optimal high-viscosity gel, a model predictive controller is designed to obtain an optimal pumping schedule necessary for producing a target fracture geometry and proppant concentration. The closed-loop simulation results demonstrate that the obtained pumping schedule successfully achieved the desired fracture geometry and proppant concentration at the end of pumping, leading to the maximum oil production from an unconventional reservoir. Published by Elsevier Ltd.