HD-technology for Steeply Inclined and Vertical Flow: Production Optimization for Wells, Risers and Pipelines

The HD technology in the OLGA multiphase flow simulator has been extended to annular and churn flows, which are important flow regimes in wells and risers. The new models and associated flow regime transition criteria have enabled "HD" accuracy for steeply inclined and vertical flows. The reduced uncertainty gives higher precision and more confidence in the design and operation of multiphase pipelines. This reduces cost, improves safety and is better for the environment. In 2012, the expert jury in Aftenposten's competition to find Norway's best invention since 1980 awarded the prize to "multiphase technology". Multiphase technology allows oil, gas and production water to be transported safely from offshore oil and gas reservoirs to a platform or an onshore processing plant. This makes oil and gas production much less expensive and more energy efficient. It also allows for field developments that would otherwise be uneconomical. Other advantages are better safety for people and the environment, with less pollution and lower greenhouse gas emissions. OLGA is a computer program that simulates multiphase flow through pipelines. OLGA is applied for design decisions, such as e.g., determining the optimal pipeline trajectory or pipe diameter and for production decisions, e.g., determining ramp up rates to prevent flooding of the receiving facilities. Multiphase flow in pipelines is complex in nature and involves many different flow regimes, and simulation results come with an appreciable uncertainty. The HD technology is a novel approach based on an advanced physics description of the flow over a pipe cross section that significantly improves the accuracy of the simulations. Previously, it was applied only for stratified flows, typically found in pipelines close to the horizonal. Now, the HD technology has been extended to annular and churn flows, which are important flow regimes in steeply inclined or vertical wells and risers. Annular flow is associated with high gas rates and consist of a relatively thin liquid film on the pipe wall surrounding a gas core with a significant number of liquid droplets. Churn flow may be perceived as an unstable and highly chaotic annular flow that emerges at lower gas rates, when gravity forces become important. We have also developed the corresponding flow regime transition criteria to allow the models to work together with the other flow models in OLGA. Verification results show that the new models outperform the current OLGA models for pressure drop predictions. The models also have better scaling properties with respect to water cut, gas density, and pipe diameter. A beta version of OLGA with the new HD models has been shared with the national and international project partners, who will test it on their multiphase flow pipelines located worldwide. Commercialization of the new HD-technology will proceed upon completion of industry validation.

Outcomes for Schlumberger Extending the HD technology in OLGA to new flow regimes may help grow the market of Schlumberger's principal multiphase flow simulator. Outcomes for project partners The unparalleled combination of functionality and accuracy offered by the extended HD-technology will help keep the project partners at the forefront of multiphase flow simulation. Impacts More accurate multiphase flow models will help the technology users (oil and gas operators) to improve the safety, profitability, reliability, and environmental performance of their development projects and operations. This will in turn lead to enhanced global scale ability to meet the ever-growing energy demands, create economic opportunities for society through resilient industry, and reduce carbon emissions from oil and gas activities. This effort aligns with UN sustainable development goals: affordable and clean energy, decent work and economic growth, and climate actions.