This study aimed to solve the problems of sealing and tearing failure of packer’s rubber cylinders during CO2 downhole injection. Using the simulation software, Comsol, a rubber cylinder model in a supercritical CO2 (SC-CO2) environment was established. The thermal analogy method was used to simulate the CO2 diffusion and rubber cylinder swelling process, thus we analyzed the deformation and stress of the rubber cylinder caused by temperature, pressure and CO2 as swelling agent. Results showed that, in the SC-CO2 environment, under the influence of CO2 diffusion and the consequent swelling, the rubber cylinder body is prone to large deformation, and the maximum shear stress is significantly increased, leading to shear failure of the rubber cylinder. The reduction of the initial seating pressure can alleviate the impact of deformation, whereas the reduction of the maximum contact pressure could cause the rubber cylinder to lose its seal. We also analyzed the change rules between various factors and the maximum contact pressure of the rubber cylinder, which provides a theoretical basis and technical support for improving the sealing performance of the packer’s rubber cylinder in the SC-CO2 environment.

Non-natural mineralization of CaCO3 with special structures or morphology is generated during the crude oil migration, which is the main scale of alkaline/surfactant/polymer (ASP) flooding in oilfields, adversely affecting the oil recovery and causing environmental pollution. Up to now, the mineralization of superstructural symbiotic aragonites and the role of heavy alkyl-benzene sulfonate (HABS) in directing mineralization are still unclear. In this work, rosette-like, bouquet-like and dumbbell-like aragonite-based superstructure of symbiotic CaCO3 crystals were obtained in a simulated O/W emulsion with HABS, which can help understanding the diversified growth of CaCO3 scaling in oilfield. As a result, HABS stabilized micelles acted as a framework for mineralization, and promoted the accumulation of Ca2+ and CO32-, generating pre-nucleation clusters and partial ion pairs by electrostatic attraction. Following, the sequential nucleation of amorphous CaCO3 interconnected with HABS molecules. Finally, these nanoparticles transformed into micro-meter crystals via dissolution-reprecipitation, forming the superstructures that controlled by a synergistic effect between HABS and kerosene phase. This work may enrich the understanding of CaCO3 mineralization in oilfield, provide theoretical support for the prevention of hard carbonate scaling, and also provide a novel strategy for organic-inorganic composites manufacturing.