Comparative Study on Enhanced Oil Recovery Effect of Amphiphilic Nanomaterials - Experiment and Mechanism Investigation

Abstract

ABSTRACT: Due to the transcendental property of nanoparticle, nanoparticle fluid flooding becomes one of the enhanced oil recovery (EOR) technique, which had played a significant role in tight oil exploitation in the worldwide scale recent years. In particular, the amphiphilic nanomaterials can greatly increase the oil recovery. To provide some guidance in selecting nanomaterials for flooding, 3 kinds of amphiphilic nanomaterials, including silicon dioxide (SiO2), graphene oxide (GO) and molybdenum disulfide (MoS2), are chosen to serve as object of the study. In lab, the physical properties were systematically characterized and flooding was conducted. Further, the morphology character of nanomaterials was placed extra emphasis and the mechanisms of EOR were also studied. The purpose was to find the link between the morphology of nanomaterials and EOR. Flooding experiment revealed that MoS2 were able to enhance the oil recovery by approximately 11%, which were better that of the others. From the above, it can be inferred that spherical materials have a "point-to-surface" contact at multiphase interfaces, while sheet materials can achieve a "surface-to-surface" contact with a higher interfacial activity. In addition, the film-climbing characteristics of amphiphilic nanomaterials were found in the experiment, which may be one of the potential reasons for enhanced oil recovery. 1. INTRODUCTION Most of the world’s oil fields have experienced primary and secondary oil recovery, with severe declines in well production and increases in water content. Combined with unfavourable conditions such as low reservoir permeability, about 50% or more of the crude oil cannot be successfully recovered (Alija et al, 2018). Chemical drive is a commonly used method to enhance recovery and is widely used in China, but with the gradual expansion of unconventional reservoir development, the main application of chemical drive has shifted to low-permeability and ultra-low-porosity reservoirs. Due to the small pore size and large specific surface area of low-permeability and ultra-low-permeability reservoirs, they have unfavourable factors such as high start-up pressure gradients and insufficient formation energy, and the development of these reservoirs is mainly based on water injection, resulting in problems such as "no injection, no recovery" in low-permeability and ultra-low-permeability reservoirs (LI Weicai et al, 2011; DOU Hong en et al, 2014; LI Xiangfang en et al, 2020). This has become one of the current issues of concern in terms of EOR.