New explicit solver for pipeline networks

The development of LedaFlow is linked to the needs of the oil and gas industry and it is validated against field data. A central aspect of the project is to gather industrial users of LedaFlow to identify relevant areas of further development, to collect relevant field data for benchmarking and use industry experts as advisors. Future oil and gas production assets will look more complex with larger networks as existing facilities will be connected to new deeper and farther fields using longer tiebacks. New approach using tiebacks can help reduce CO2 emissions via fewer new topside e.g. steel structures. Tiebacks and riser design challenges is where we would like to deploy predictive capabilities of Ledaflow. During production LedaFlow is used to keep the fields outside slugging conditions, or to handle slugging. Slug Capturing is a step change in the simulation of transient multiphase flows, and allows predicting the transient development of the flow, in particular slugs. In Slug Capturing, the slugs are resolved on the grid, hence slugs are an alternation of stratified and bubbly flow sections. This requires a much more accurate numerical solver than with the averaged correlations. An explicit solver has been chosen for its greatly reduced numerical diffusion, as well as its ability for parallelization to utilize cloud servers. We have already released this technology for single pipelines, and we will now extend and demonstrate the technology for pipeline networks. To consider the full range of possible fluid chemistry, the energy balance and composition tracking functionality need to be reimplemented in the new solver. Finally, all the devices that can be present on or in a pipe need to be made compatible. When the required functionalities are supported, simulation data will be verified against the field data collected from the project's industrial partners and used to identify gaps where the model is not performing well enough, and to guide further enhancements.

LedaFlow has already proven and demonstrated a new explicit solver for single pipe Slug Capturing 2 that improved speed and accuracy for multiphase flow simulations. However, for complex fields the new Slug Capturing 2 technology still falls short since we fail to match new field data received via an ongoing LedaFlow Demonstration JIP (LIFT III). One such failed application is calculation of fatigue contribution in deep-water risers due to slugging initiated in connected tiebacks. This has far-reaching consequences from oil leaks if not estimated properly and hence under-designed. We also see that the current limitation to single pipe falls short on comparison vs. field data since we are missing capability of addressing the entire system e.g. network of pipelines and wells. LedaFlow Technologies DA has financed a research activity to develop this functionality through Explicit Solver Project and we would like to combine the results of this project with the ongoing Demonstration JIP by expanding the scope to demonstrate new explicit solver for network of pipelines. This requires new type of numerical integration for our explicit solver that needs to be demonstrated by matching the new field data more accurately. This new explicit network solver for pipe-networks is unique amongst multiphase flow simulators in the market and can be used in several future applications as well. For example, it can be used in CCUS applications that may require the increased accuracy that is offered by explicit solvers compared to more common implicit solvers. We also intend to use the new capability as infrastructure to deploy results from another ongoing innovation project Chemflow IPN (Project Number 329658). Early indications are that results from Chemflow IPN together with explicit network solver could potentially help cover the gaps we mention above vs. field data. Investigation and demonstration of such improvement is an urgent need but is not in scope of any ongoing projects.