Many offshore drilling sites are plagued by infrastructure break-downs and other issues due to the complexity of the systems required for the subsea extraction of oil and gas (O&G). For the most part, the O&G industry uses multi-phase and multi-component pipeline flows to move their product from one site to another or to different areas of the same site. In extreme environments, such as offshore or Arctic sites, the development of Sand particles along the pipelines can bring additional challenges to the project. The present work examines the practicality of applying a system of four-phase four-fluid flows for transporting a multi-phase flow (sand, water, oil and CO2) along subsea pipelines. As a means for precisely measuring and predicting the characteristics of thermo- and hydro-dynamic multi-component mixtures, models representing phase behavior and hydrate equilibrium are built and tested. Additionally, the study looks at heat transfer, mass and momentum in both the flow and pipe walls and develops equations to describe their interrelationships. Another focus of this work it to investigate four-phase multi-component flow systems in order to obtain a deeper understanding of transient flow in various types of pipes, including conditions around the system of four-phase four-fluid flows, and hydro-dynamic variable effects on flow.