Investigation on microscopic invasion characteristics and retention mechanism of fracturing fluid in fractured porous media
Investigation on microscopic invasion characteristics and retention mechanism of fracturing fluid in fractured porous media
复制标题
裂缝性多孔介质中压裂液微观侵入特征及滞留机制研究
DOI：
10.1016/j.petsci.2022.03.009
复制
发表时间：
2022-08-01
影响因子：
5.6
通讯作者：
Lei, Guang-Lun
中科院分区：
文献类型：
--
作者：
Da, Qi-An;Yao, Chuan-Jin;Lei, Guang-Lun
瓜尔胶压裂液和浮水对储层的伤害严重影响后续的油气生产。然而，压裂液在裂缝基质层中的侵入特征和滞留机理尚不清楚。在这项工作中，设计了一个反映断裂基质区特征的微观模型。基于微流体实验方法，直观地研究了压裂液在裂缝基质层中的侵入、返排和滞留过程，并对其进行了定量表征。分析和阐明了影响压裂液在裂缝基质带滞留的因素和机理。结果表明，在侵入过程中，在相同的侵入压力下，油水的正面波及范围大于瓜尔胶压裂液，驱油效率和伤害程度低于瓜尔胶压裂液。随着侵入压力的增加，浮水的破损率从61.09%增加到82.77%，瓜尔胶压裂液的破损率从93.45%下降到83.36%。在后续采油之前，侵入的压裂液主要集中在裂缝基质带的中高渗透区。滑水的阻力主要是毛细管力，瓜尔胶压裂液的阻力主要是粘性阻力。压裂液滞留在低渗透区和裂缝末端附近最为严重。实验和数值模拟结果表明，增大生产压差可以改善裂缝基质层的速度场分布，增大返排波及范围，最终降低压裂液的滞留率。油水在裂缝基质层的滞留机理包括乳状液滞留和流场滞留，而瓜尔胶压裂液的滞留机理包括粘滞滞留和流场滞留。乳状液滞留是毛细管力和截流作用共同作用的结果。粘滞性是由聚合物的粘性阻力引起的，而流场滞留是由于排液速度分布不均匀造成的。(C)2022年提交人。爱思唯尔公司代表科爱通信有限公司发布服务。这是CC BY-NC-ND许可证(http://creativecommons.org/licenses/by-nc-nd/4.0中的一篇开放获取文章。
Reservoir damage caused by guar gum fracturing fluid and slick water seriously affects the subsequent oil and gas production. However, the invasion characteristics and retention mechanisms of fracturing fluids in the fracture-matrix zone are still unclear. In this work, a microscopic model reflecting the charac-teristics of the fracture-matrix zone was designed. Based on the microfluidic experimental method, the process of fracturing fluid invasion, flowback and retention in the fracture-matrix zone was investigated visually and characterized quantitatively. The factors and mechanisms affecting fracturing fluid retention in the fracture-matrix zone were analyzed and clarified. The results indicated that in the invasion pro-cess, the frontal swept range of slick water was larger than that of the guar gum fracturing fluid, and the oil displacement efficiency and damage rate were lower than those of the guar gum fracturing fluid under the same invasion pressure. With the increase in invasion pressure, the damage rate of slick water increased from 61.09% to 82.77%, and that of the guar gum fracturing fluid decreased from 93.45% to 83.36%. Before subsequent oil production, the invaded fracturing fluid was mainly concentrated in the medium-high permeability area of the fracture-matrix zone. The main resistance of slick water was capillary force, while that of the guar fracturing fluid was mainly viscous resistance. The fracturing fluid retention was most serious in the low permeability region and the region near the end of the fracture. The experimental and numerical simulation results showed that increasing the production pressure difference could improve the velocity field distribution of the fracture-matrix zone, increase the flowback swept range and finally reduce the retention rate of the fracture fluid. The retention mechanisms of slick water in the fracture-matrix zone include emulsion retention and flow field retention, while those of the guar gum fracturing fluid include viscous retention and flow field retention. Emulsion retention is caused by capillary force and flow interception effect. Viscous retention is caused by the viscous resistance of polymer, while flow-field retention is caused by uneven distribution of flowback velocity. (c) 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).