To improve pipeline performance, oil scheduling accuracy, and predictive maintenance, Flownex can be used as a powerful tool in pipeline simulation technology. Building on our previous exploration of how ambient temperature affects pipeline flow rates [1], this post will focus on investigating how the oil temperature extracted from sea-bound oil tankers influences land-based pipeline operational parameters using transient analysis in Flownex.
Critical Factors Impacting the Flow of Crude Oil in Pipelines
The flow of crude oil in pipelines is influenced by various factors, including the oil's properties like density and viscosity, temperature variations, pipeline design, and components like pumps. Flownex allows users to construct a detailed virtual model of a pipeline, taking into account variables such as viscosity, temperature, elevation, and operational conditions. This aids the maintenance engineer in conducting a thorough analysis and making predictions about pipeline performance.
Crude Oil Pipeline Simulation Using Flownex
To model the crude oil pipeline in Flownex, we lay out a flow network for the pipeline route and use pipes, nodes, reservoirs, pumps, and other components to construct the pipeline. After that, we define component details, such as pipe dimensions and roughness, and geographical specifications, such as elevation. Then, we input the physical properties of the crude oil, like density and viscosity, along with operational parameters like pressure and temperature using boundary conditions.
A flow network is created in Flownex for the crude oil pipeline, from oil tankers and offshore terminals to onshore facilities like booster pump stations and scheduling facilities, as shown below. Further details about constructing this flow network in Flownex can be found in a separate blog post; the link to access it is provided at the end of this article [1].
Pipeline Performance Evaluation for Oil Temperature Variations
The pipeline model was initially simulated at an oil temperature of 60 °C to represent hot crude oil conditions, and then rerun at 20 °C to simulate cold crude oil. The pipeline delivers 5% less to the reservoir on land when the temperature changes from 60°C to 20°C, attributed to the higher viscosity of cold oil flowing through the pipeline. Users can also analyze pressure drops, temperature gradients, and flow velocities across different sections of the pipeline.
The above results are obtained for steady-state simulation in Flownex for two different oil temperatures for the above flow network. If the oil temperature changes abruptly from 20°C to 60°C, we can use Flownex's transient simulation feature to assess the operational conditions and pipeline performance. This will allow us to evaluate the transient effects of the temperature change on the pipeline's operational parameters.
The steps for running transient simulations in Flownex are as follows:
- Set a Scheduler for a transient simulation.
- Create a Scenario and configure the necessary Actions to change properties during the simulation.
- Set up Graphs to view results changing over time.
- Create a Snap (snapshot) to save simulation results at specified times, which can be reloaded at any time
We conducted a transient simulation of the flow network to examine the impact of a sudden change in oil temperature from 20°C to 60°C on pipeline delivery to reservoirs and temperature distribution along the pipeline. The graph depicts the temperature variation at three points along the pipeline. It shows that the temperature at the Single Point Mooring (SMP) quickly tracks the crude oil temperature from the tankers (blue line), while the temperature at the inlet to the Marine Terminal follows the temperature change with a delay (red line). However, the thermal inertia of the network dissipates before reaching the reservoir inlet (green line).
A video has been created to demonstrate the process of conducting transient simulations on the flow network mentioned above. The simulation focuses on modeling the sudden change in temperature boundary conditions from the tanker (Single Point Mooring) and its effects on temperature variations in the crude oil pipeline.
You can click this link to view the video on YouTube: https://youtu.be/FLmIlk2yABQ
[1] Modeling Thermal Environment Effects on Crude Oil Transportation using Flownex: https://blog.ozeninc.com/resources/simulating-crude-oil-pipeline-flow-with-flownex