Experimental investigation of the effect of the chemical flooding on the effective zeta potential in rock samples - improved understanding of the EOR

本研究的目的是实验确定控制矿化度水驱（CSW）（低矿化度效应）对化学驱的影响。这将通过测量诸如受化学驱和CSW方案影响的ζ电位等参数来实现，并观察这些参数中由于协同作用而产生的任何额外变化是否与对增加的石油采收率的有意义的积极影响相关。这个博士的灵感来自最近的证据表明，在油-盐水和矿物-盐水界面的zeta电位的变化导致在CSW实验中的润湿状态的变化。在CSW实验中将润湿状态改变为混合润湿状态和在化学驱中将润湿状态改变为混合/水润湿状态之前已被确定为有利于增加增量采油。因此，这项研究应该提高我们对润湿性控制的理解，并可以提高这些洪水schemes.The工作计划为这个博士学位包括：文献综述和荟萃分析的化学驱和CSW在碳酸盐岩和砂岩，实验工作，包括单相和多相行为测试和岩心驱油实验。单相实验将侧重于测量描述储层（岩石样品）和流体（地层盐水、注入盐水或原油）如何相互作用的关键参数，例如矿物-盐水界面的渗透率和zeta电位。多相实验将与岩心驱替实验同时进行，岩心驱替实验将确定驱替的最终石油采收率，并允许确定石油、地层盐水和注入盐水如何相互作用的许多因素，例如：石油-盐水和矿物-盐水界面的相对渗透率和zeta电位测量。该设备将能够采取现场读数，使这些参数的变化可以在真实的时间监测。实验将在常规储层条件下进行，并将评估初始盐水、油和流出物的性质和组成。改变的变量以及如何操纵它们以在本实验中实现最佳结果将通过文献综述和荟萃分析以及单阶段和多阶段行为测试来确定。已被确定为潜在进一步研究的其他子目标包括：通过减少化学品的使用量来优化CSW化学驱，以实现与常规化学驱相似的性能，地层盐水中锶的影响、实验温度的改变、不同地层（碳酸盐岩和砂岩）以及硬、软含水层水替代海水作为CSW方案的组成部分对化学驱+ CSW性能的影响。该项目将作为一种潜在的新型提高石油采收率技术在石油工业中应用。该项目还旨在通过确定以前未考虑的因素（如油-盐水和矿物盐水界面的zeta电位）如何影响最终的石油采收率，提高我们对化学驱及其与CSW的协同效应的理解。考虑到这些因素可以解释为什么一些CSW和化学洪水失败或表现不佳。

The aim of this research is to determine experimentally the effects controlled salinity waterflooding (CSW) (low-salinity effect) has on chemical floods. This will be achieved by measuring parameters such as the zeta potential that are influenced by both chemical flood and CSW schemes and to observe if any additional changes in these parameters due to synergy correlate to a meaningful positive influence on incremental oil recovery. The inspiration for this PhD came from recent evidence that suggested that changes in the zeta potential of the oil-brine and mineral-brine interfaces lead to changes in the wetting state in CSW experiments. Changing of the wetting state to mixed-wet in CSW experiments and mixed/water-wet in chemical floods have been identified previously as favourable to increase incremental oil recovery. Hence this research should improve our understanding of wettability control and can improve the performance of these flood schemes.The work planned for this PhD includes: a literature review and meta-analysis of chemical floods and CSW in carbonates and sandstones, experimental work including single-phase & multi-phase behaviour tests and core flood experiments. The single-phase experiments will focus on measuring the key parameters that characterise how the reservoir (rock sample) and fluids (formation brine, injection brine or crude oil) interact with each other such as permeability and zeta potential of the mineral-brine interface. The multi-phase experiments will be conducted at the same time as the core flood experiments which will determine the ultimate oil recovery of the flood and will allow for the determination of many factors that characterise how the oil, formation brine and injected brine interact with each other such as: relative permeability and zeta-potential measurements of the oil-brine and mineral-brine interface. The equipment will be capable of taking live readings so changes in these parameters can be monitored in real time. The experiments will be performed at conventional reservoir conditions and the properties and compositions of the initial brines, oils and effluents will be evaluated. The altered variables and how they will be manipulated to achieve optimum results in this experiment will be determined by the literature review & meta-analysis and by the single-phase and multi-phase behaviour tests.Other sub-objectives that have been identified as potential further research include: optimising chemical floods with CSW by reducing the amount of chemical used to achieve similar performance to conventional chemical floods, the effects of strontium in the formation brine, alteration of the temperature the experiments are performed at, different formations (carbonates and sandstones) and what effects hard and soft aquifer water replacing seawater as a component of the CSW scheme has on the performance of chemical flooding + CSW.This project will have applications in the oil industry as a potential novel enhanced oil recovery technique. The project also aims to enhance our understanding of chemical floods and its synergistic effects with CSW by determining how factors that haven't previously been considered such as the zeta potential of the oil-brine and mineral brine interface influence ultimate oil recovery. Accounting for these factors could explain why some CSW and chemical floods either fail or underperform.