大裂缝致密油藏渗吸置换数学模型及浸泡时间优化,ACS Omega

当前位置： X-MOL 学术 › ACS Omega › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

大裂缝致密油藏渗吸置换数学模型及浸泡时间优化
ACS Omega ( IF 3.7 ) Pub Date : 2023-09-13 , DOI: 10.1021/acsomega.3c04576
Yunfeng Liu ₁ , Yangwen Zhu ₁ , Haiying Liao ₁ , Hongmin Yu ₁ , Xin Fang ₁ , Yao Zhang ₁

Affiliation

由于致密油储层孔喉小、毛细管压力强等特点，渗吸置换成为一种有效的开发方法。现场数据表明，只有少量压裂液可以回流，并且体积压裂后关井期的石油采收率有所提高。大量学者针对渗吸特性开展了岩心尺度的实验，但对逆流渗吸过程中的压差和渗吸置换的定量表征研究还很有限。同时，对于最佳浸泡时间的计算方法也存在争议。本文首先建立了油水两相流的数学模型。然后，利用导流函数导出了表示致密储层压差和渗吸置换的数学模型。基于饱和度方程、Corey相对渗透率曲线和J函数，将模型简化为体积压裂关井后自渗数学模型。其次，基于有限差分法，建立了考虑动态毛细管力的流场动态求解方法，揭示了浸泡过程中压力场和含水饱和度场的变化规律。模拟结果表明，渗吸特性是流场重构的核心，压差作用可以保证压裂液的推进距离；两者对于致密油开发并不是线性叠加，而是相辅相成、相互促进的。第三，根据浸泡时间内裂缝与基质之间渗吸置换的增长速率，建立了最佳浸泡时间的计算方法。结合鄂尔多斯盆地体积压裂开发实例的开发参数，优化合理的浸泡时间。最后，我们分析了不同条件下的最佳浸泡时间，并绘制了不同初始化的最佳浸泡时间图表。这样的图表对于工程师来说具有深远的参考意义，可以快速准确地做出开发和调整决策。

"点击查看英文标题和摘要"

Mathematical Model of Imbibition Replacement and Optimization of Soaking Time for Massively Fractured Tight Oil Reservoirs

Due to the small pore throat characteristics of tight oil reservoirs, their strong capillary pressure makes imbibition replacement an effective development method. Field data has indicated that only a little fracture fluid can flow back and that there is an enhancement in oil recovery with shut-in periods after volume fracturing. A large number of scholars have carried out core-scale experiments on imbibition characteristics, but there has been limited research on the quantitative characterization of the differential pressure and imbibition replacement during counter-current imbibition. At the same time, there was also controversy on the calculation method of the optimal soaking time. In this paper, a mathematical model of oil–water two-phase flow is first established. Then, a mathematical model representing differential pressure and imbibition replacement in tight reservoirs is derived with a diversion function. Based on the saturation equation, Corey relative–permeability curve, and J function, the model is simplified to a mathematical model of spontaneous imbibition in the shut-in periods after volume fracturing. Second, based on the finite difference method, a dynamic solution method for the flow field considering the dynamic capillary force was established, and the variation law of the pressure field and the water saturation field during the soaking time was revealed. The simulation results show that imbibition characteristics are the core of flow field reconstruction, and the differential pressure action can ensure the advancing distance of the fracturing fluid; both of them are not a linear superposition on tight oil development but complement each other and promote each other. Third, according to the growth rate of the imbibition replacement between fractures and the matrix during the soaking time, the calculation method of optimal soaking time was established. Taking the development parameters of the volume fracturing development case in the Ordos Basin into account, a reasonable soaking time was optimized. Finally, we analyzed the optimal soaking time under different conditions, and a chart of optimal soaking time for different initializations was plotted. Such a chart has profound reference significance for engineers, and they can make quick and accurate decisions regarding development and adjustment.

更新日期：2023-09-13

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南