Underground compressed air energy storage (CAES) in naturally fractured depleted oil reservoir: Influence of fracture
在过去十年中，为满足人类需求的清洁能源供应来源受到了全球研究人员的极大关注。地下压缩空气储存是平衡能源生产和消费的绝佳方式。在非高峰时段，利用过剩的电能，将空气暂时以高压储存在所需环境中。储存的压缩空气在需要的小时和高峰能源消费期间产生恢复的电能。由于具有适合空气储存的容量，并且其地质特征已经被很好地识别，包括枯竭的油气储层在内的地下构造中的压缩空气储能是储存方法之一。为了在含水层和盐穴中储存压缩空气，已经进行了研究，但迄今为止，尚未进行有关在天然裂缝枯竭油藏中储存压缩空气的研究。
本研究模拟了在天然裂缝枯竭油藏中储存压缩空气，裂缝对氧化反应速率、空气溶解和空气在油水相中扩散的影响。此外，首次通过数值模拟检查了裂缝属性，包括孔隙度、渗透率和裂缝间距对CAES期间空气回采量的影响。显著提高裂缝孔隙度和渗透率可以改善空气回采，并分别导致空气采收率增加19%和16%。在裂缝储层中，增加裂缝孔隙度对降低空气采收率影响最大，减少裂缝间距对空气回采的影响最小。最后，这项研究的结果表明，由于在裂缝储层中与常规储层相比空气的消耗和损失，裂缝储层中的空气回采率小于常规储层。
CMG软件应用情况
在本研究中，使用CMG软件的STARS模块对天然裂缝枯竭油藏中的压缩空气储能进行了数值模拟。模拟包括地下压缩空气储存的两个阶段：第一阶段是注入垫气气体形成初始气泡；第二阶段包括空气生产和注入的操作周期。通过模拟，研究了裂缝的存在及其属性（孔隙度、渗透率、裂缝间距）对空气采出因子的影响。模拟结果显示，在裂缝储层中，由于裂缝的高渗透性，空气更远离注入区域，并且更倾向于不进入基质。因此，与常规储层相比，裂缝储层中空气与储层的接触更多，导致空气在油水相中的溶解和扩散增加，氧化反应也增加，从而增加了空气的消耗和损失。
Highlights
- Compressed air storage in a naturally fractured depleted oil reservoir was numerically simulated.
- Increasing the fracture porosity has the most significant effect on increasing air recovery.
- The air recovery factor in the fractured reservoirs is less than the conventional reservoirs.
Abstract
In the last decade, the sources of clean energy supply to meet human needs have been given much attention by researchers worldwide. Compressed air storage in underground formations is an excellent way to balance energy production and consumption. During off-peak hours, with the consumption of excess electrical energy, the air is temporarily stored at high pressure in the desired environment. The stored compressed air produces recovered electrical power during the needed hours and peak energy consumption. Compressed air energy storage in underground structures, including depleted hydrocarbon reservoirs, due to having a suitable storage capacity for air and because their geological characteristics have already been well identified, is one of the storage methods. In order to underground storage of compressed air in aquifers and salt caverns, research have been carried out, but so far, studies have yet to be carried out regarding the storage of compressed air in depleted natural fractured oil reservoirs.
This study simulated the storage of compressed air in a naturally fractured depleted oil reservoir, the effect of fracture on the rate of oxidation reactions, air dissolution and air diffusion in the oil and water phases. Also, for the first time, an examination of the fracture properties, including porosity, permeability, and fracture spacing on the amount of air recovery during CAES, was numerically simulated. Significantly Increasing the fracture porosity and permeability improves the air recovery and leads to a 19% and 16% respectively increase in the air recovery factor. In the fractured reservoir, increasing the fracture porosity has the most significant effect on reducing the air recovery factor and reducing the fracture spacing has the most negligible effect on the air recovery. Finally, the results of this study showed that due to the consumption and loss of air in the fractured reservoir compared to the conventional reservoir, the air recovery factor in the fractured reservoirs is less than the conventional reservoirs.
作者单位
伊朗德黑兰大学
