In the oil field production, carbon dioxide flooding technology has become increasingly common for high water-cut oilfields. It not only reduces carbon emissions, but also greatly improves the efficiency of oil production. In the process of oil field gathering and transportation, most high water-cut crude oil pipelines have achieved in non-heating transportation technique, which means even the temperature drops below the gel point of crude oil, pipelines can still run safely. Especially for carbon dioxide flooding gathering and transportation pipeline, the presence of carbon dioxide can effectively improve the flow characteristics of crude oil and make it easier to achieve non-heating transportation. In the study of non-heating transportation, wall sticking occurrence temperature (WSOT) and quality of the wall-filled congealed oil are the most important research objectives. When the temperature is between the gel point of crude oil and WSOT, the crude oil gel only forms a thin oil layer on the pipe wall, which does not affect the safe operation of the pipeline. Once the temperature drops below WSOT, a large amount of congealed oil will stick to the pipe wall, reducing the inner diameter of the pipe and increasing the risk of plugging.

In this paper, two self-developed devices were used to study the changes of viscosity and wax appearance temperature of dissolved carbon dioxide crude oil and the influence of carbon dioxide on WSOT and quality of the wall-filled congealed oil in oil-gas-water system, respectively. It is found that the viscosity and wax appearance temperature of crude oil are reduced after dissolving carbon dioxide, which lead to the less amount of the wall-filled congealed oil in the gathering and transportation process. In addition, the WSOT of dissolved gas-oil-water system is about 10 °C lower than the gel point of the crude oil, which is the same as the oil-water system. What’s more, due to the shear action of water current and airflow in actual pipeline, the experimental results are more conservative compared to the operating results of oilfield pipeline. In a word, the research methods mentioned in this paper are suitable for the study of non-heating transportation of carbon dioxide flooding gathering and transportation pipeline, and the development of gathering and transportation scheme can enjoy some benefits from this work.


The Study on Non-Heating Transportation of Carbon Dioxide Flooding Gathering and Transportation Pipeline

Division / Sponsors: 
Pipeline Systems Division

Paper Proceedings: https://asmedigitalcollection.asme.org/IPC/IPC2020/volume/84447

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