Improved Oil Recovery from Sub-Optimal Reservoirs

该计划旨在帮助加拿大石油工业目前正在努力从边际质量的油藏中经济地生产石油。这些包括对于露天开采来说太深但对于正常SAGD操作来说不够深的沥青矿床、天然裂缝碳酸盐地层中的重油矿床、薄重油地层、已经通过冷生产耗尽但仍然含有高油饱和度的重油矿床。 拟议的工作涉及实验和理论研究的机制，在改善石油回收过程和修改现有的技术，以克服其缺点，从次优质量的油藏回收石油。以下研究主题被提议为这个计划的延续。 I.天然裂缝性油藏中的溶剂辅助重力泄油：在天然裂缝性油藏中发现了大量的重油和超重油，但成功开采此类油藏仍然具有挑战性。像蒸汽辅助重力泄油和循环蒸汽刺激这样的热处理不能很好地工作，因为储层孔隙度通常很低，并且每单位体积的油必须加热的岩石体积变得太大。低孔隙率在基于溶剂的非热方法中不是问题，但是这种方法通常不能提供足够高的油生产率。该项目旨在寻找提高非热过程采油率的方法。 二.用于改进聚合物驱的纳米颗粒：该计划的这一部分旨在开发太薄而无法进行热采的稠油油藏。用水平威尔斯井进行的初次衰竭留下了大部分未回收的油，这是用目前可用的技术难以生产的。我们建议研究这种油藏的过程是用纳米颗粒增强聚合物溶液改进聚合物驱。我们认为，添加具有改性表面特性的纳米颗粒到聚合物溶液中可以克服目前使用聚合物进行稠油驱油的一些限制。这些限制是高粘度聚合物溶液的低注入性和注入期间聚合物的剪切降解。 三.从被CHOPS耗尽的油藏中回收重油：这项工作的重点将是开发一种可以在存在虫洞的情况下工作的稳健的循环溶剂注入工艺。将对添加油溶性发泡剂的新溶剂混合物进行评价，以找到能够重新点燃衰竭油藏中泡沫油驱动的组合。 该计划产生的知识不仅将有助于加拿大石油工业，还将提高对裂缝地层中流体流动，纳米颗粒与聚合物的相互作用以及循环溶剂过程中所涉及的机制的基本理解。

This program aims to help the Canadian oil industry currently struggling to economically produce oil from reservoirs of marginal quality. These include bitumen deposits that are too deep for surface mining but not deep enough for normal SAGD operation, heavy oil deposits in naturally fractured carbonate formations, thin heavy oil formations, heavy oil deposits that have been depleted by cold production but still contain high oil saturation. The proposed work involves experimental and theoretical examination of mechanisms involved in improved oil recovery processes and modifying the existing technologies to overcome their shortcomings in recovering oil from reservoirs of sub-optimal quality. The following research themes are proposed for the continuation of this program. i. Solvents Assisted Gravity Drainage in Naturally Fractured Reservoirs: Large volumes of heavy oil and extra heavy oil are found in naturally fractured reservoirs but successful exploitation of such reservoirs remains challenging. Thermal processes like steam assisted gravity drainage and cyclic steam stimulation do not work too well because very often the reservoir porosity is low and the volume of rock that must be heated per unit volume of oil becomes too large. The low porosity is not a problem in solvent based non thermal processes, but such processes generally fail to provide high enough oil production rates. This program aims to find ways of improving the oil recovery rate of non-thermal processes. ii. Nanoparticles for Improved Polymer Flooding: This segment of the program is aimed at exploitation of heavy oil reservoirs that are too thin for thermal recovery. Primary depletion with horizontal wells leaves a large fraction of oil unrecovered, which is difficult to produce with currently available technology. The process that we propose to examine for such reservoirs is improved polymer flooding with nanoparticle enhanced polymer solutions. We believe that addition of nanoparticles with modified surface characteristics to polymer solutions can overcome some of the current the limitations in using polymers for heavy oil displacements. These limitations are low injectivity of high viscosity polymer solutions and shear degradation of polymers during injection. iii. Recovery of Heavy Oil from Reservoirs Depleted with CHOPS: The focus of this work will be to develop a robust cyclic solvent injection process that can work in the presence of wormholes. New solvent mixtures with added oil soluble foaming agents will be evaluated to find combinations that can rekindle the foamy oil drive in the depleted reservoirs. The knowledge generated by this program will not only help the Canadian oil industry, it will also enhance the basic understanding of fluid flow in fractured formations, interactions of nanoparticles with polymers and mechanisms involved in the cyclic solvent process.