Numerical Simulation of Immiscible CO2-Assisted Gravity Drainage Process to Enhance Oil Recovery
Numerical Simulation of Immiscible CO2-Assisted Gravity Drainage Process to Enhance Oil Recovery
复制标题
非混相CO2辅助重力泄油提高采收率数值模拟
DOI：
10.24996/ijs.2020.61.8.17
复制
发表时间：
2020
影响因子：
--
通讯作者：
M. Al
中科院分区：
文献类型：
--
作者：
Dahlia A. Al;M. Al
气体辅助重力泄油（GAGD）工艺已经成为在二次和三次采油阶段以及通过非混相和混相模式提高石油采收率的最重要的工艺之一。与常规注气方法如连续注气（CGI）和水-气交替（WAG）相比，其优势在于能够提供重力稳定驱油以提高石油采收率。CO2气体的垂直注入器被放置在储层的顶部以形成气顶，气顶将油驱向位于油水接触面上方的水平产油威尔斯井。GAGD工艺在垂直威尔斯井中进行了开发和试验，以提高具有底水驱动和强水锥趋势的油藏的采收率。在环境和储层条件下研究了GAGD性能的许多物理和模拟模型，以研究该方法提高石油采收率的效果，并检查控制GAGD过程的最有效参数。基于缩比物理模型建立了不同情景下CO2辅助重力泄油的二维原型模拟模型。研究了注气速度、注气压力和采油速度对非混相CO2辅助重力泄油提高采收率的影响。结果表明，随着采油速度的增加，最终采收率显著增加。增加气体注入速率改善了工艺的性能，而高压气体注入导致较低效的重力介导的采收。
The Gas Assisted Gravity Drainage (GAGD) process has become one of the most important processes to enhance oil recovery in both secondary and tertiary recovery stages and through immiscible and miscible modes. Its advantages came from the ability to provide gravity-stable oil displacement for improving oil recovery, when compared with conventional gas injection methods such as Continuous Gas Injection (CGI) and Water – Alternative Gas (WAG). Vertical injectors for CO2 gas were placed at the top of the reservoir to form a gas cap which drives the oil towards the horizontal oil producing wells which are located above the oil-water-contact. The GAGD process was developed and tested in vertical wells to increase oil recovery in reservoirs with bottom water drive and strong water coning tendencies. Many physical and simulation models of GAGD performance were studied at ambient and reservoir conditions to investigate the effects of this method to enhance the recovery of oil and to examine the most effective parameters that control the GAGD process. A prototype 2D simulation model based on the scaled physical model was built for CO2-assisted gravity drainage in different statement scenarios. The effects of gas injection rate, gas injection pressure and oil production rate on the performance of immiscible CO2-assisted gravity drainage-enhanced oil recovery were investigated. The results revealed that the ultimate oil recovery increases considerably with increasing oil production rates. Increasing gas injection rate improves the performance of the process while high pressure gas injection leads to less effective gravity mediated recovery.