Objectives and problems to be solved: The objective of the proposed work is to generate experimental data on three-phase slug flow in complex terrain requested for a better understanding multiphase slug flow and for further development and validation of commercial computer codes used in the development of offshore production process. It should then help to prevent slug formation and have a positive impact on safety and pipeline management. A decrease of OPEX and CAPEX and, consequently, a better competitiveness in the oil and gas exploitation is expected. To access at the cost effective and suitable technologies a strong collaboration between engineering companies, oil operating companies and research institutes is requested. It will encourage the sharing of the scientific and technical experience for a competitive Europe.So the benefits of this project are high as improved multiphase flow codes may allow Oil companies to produce tomorrow fields currently not profitable (production costs too expensive, marginal satellite fields, deep offshore technology, etc.).Description of the work: In this project four of the leading multiphase flow R&D-groups in Europe are co-ordinating their efforts to expand the current knowledge of three-phase slug flow to include a more comprehensive understanding of slug development and three-phase terrain induced slugging. This will be achieved through an extensive set of three-phase flow experiments to be performed by each of the four participating research groups, all with complementary experimental facilities. The most important sub-models required are the propagation velocity of slug bubbles, the amount of dispersed bubbles in the slug, the pressure profile in the slug unit and the oil-water slip for separated oil-water flow. The project will perform detailed observations under what conditions the oil and water phases are mixed and how oil/water mixtures behave with respect to phase distribution and pressure losses. Slug length and slug growth data will be needed to determine slug initiation models to verify computations of the following possible growth of slugs induced by pipe topology (terrain) and flow-rates. The acquired data will be checked for consistency before entered into a data bank. Another significant work task will evaluate existing models in relation with the new data. Better prediction of the water behaviour in the hydrocarbon production will allow to improve corrosion predictions and hydrate formation, both being important issues for safety and pipeline operating management. Expected results and exploitation plans: The main milestones are definition of data bank format, qualification and technical description of the flow loops, and final report with a CDROM data bank. The data bank with detailed and integral three-phase slug flow data will be the main deliverable from the project. Furthermore, the identification of weaknesses in the existing software will be an extremely important information for the code developers. Through more accurate simulation tools on three-phase flows, more efficient flow regime characterisations for hydrocarbons in pipelines are expected. The data bank will be used, and is in fact a prerequisite, for further studies including commercial code validations and model development.
All the partners have provided experimental data that have been included in a Databank. It has been shown that downward conditions have a direct influence on the terrain slugging effect. On the single elongated bubble study, the results shed: new light on the process of bubble turning in downwards directed flow as well as on bubble front velocity in upward inclined pipes. On the slug-stratified flow transition, the action of the inlet water fraction on the slug characteristics has been detected. The dependence of this transition regarding the pressure (gas density) has also been enlightened.
Funding SchemeCSC - Cost-sharing contracts
SW7 2AZ London