MODELING MULTIPHASE FLOW IN DOWNHOLE VALVES
Doctoral thesis
Permanent lenke
http://hdl.handle.net/11250/298986Utgivelsesdato
2015Metadata
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Sammendrag
Oil and gas have been produced from onshore and offshore fields for more than
100 years, and production rates are falling for the most easily accessible fields.
New oil fields are found at deeper and more remote areas, and exploration costs
are increasing. A new tool that can enhance the well testing process is a wireline
operated downhole shut-in valve. In order to get as precise as possible results
from the well testing, the two-phase pressure drop across the shut-in valve must be
known.
The flow path through this shut-in valve is however complex and cannot easily be
compared to standard tubing parts and singularities. Frictional pressure losses in
pipes are well understood now and have been studied by a number of authors since
the late forties. Minor pressure losses arise from singularities like bends, contractions,
expansions etc. Two-phase flow minor losses have also been studied by
many authors, but only for well-defined and common shapes like bends, nozzles,
sharp edged contractions etc. In a typical industrial application like the shut-in
valve, the flow path is complex. More research is therefore needed in order to be
able to predict the two-phase pressure drop in a complex flow path. The modeling
methods developed here should hopefully be applicable to other two-phase flow
systems as well.
The main objective for this work is therefore to find methods for modeling twophase
flow in complex geometries with several singularities and changes of cross
section. The work has included design, construction and instrumentation of a full
scale shut-in valve mock-up. A series of experiments have been performed with
two-phase flow of air, water and two different oil types. This provides a valuable
experimental data base for two-phase flow in a typical downhole valve. Furthermore
an in-house simulation tool for 1-D models was implement, verified and validated.
The first achievement in this thesis is the validation of 3-dimensional computational
fluid dynamics (CFD) simulations of single-phase flow in the valve. Provided
that the mesh is properly designed etc. the deviation in pressure drop is only 3-6%
compared to experimental data.
The next achievement is the 1-D modeling of the flow in the valve. This 1-D model
serves as a necessary basis for the two-phase simulations.
The main achievement is the implementation of two-phase flow in the 1-D model.
Two approaches are used. First classical flow pattern independent correlations are
applied, and then the state-of-the-art Unified Comprehensive Model formulation is
introduced. The latter provides the best results with only some 10% deviation in
pressure drop.
Består av
Paper 1: Edvardsen, Svein; Nydal, Ole Jørgen; Dorao, Carlos Alberto. Two-phase Flow in a Down-hole Shut-in Valve. I: 9th North American Conference on Multiphase Technology 2014. BHR Group 2014Paper 2: Edvardsen, Svein; Dorao, Carlos Alberto; Nydal, Ole Jørgen. Experimental and numerical study of single-phase pressure drop in downhole shut-in valve. Journal of Natural Gas Science and Engineering 2015 ;Volum 22. s. 214-226 http://dx.doi.org/10.1016/j.jngse.2014.11.034 The article is reprinted with kind permission from Elsevier, sciencedirect.com
Paper 3: Edvardsen, Svein; Dorao, Carlos Alberto; Nydal, Ole Jørgen. Multiphase flow in complex valve geometry. Energy Procedia 2015 s. 91-100 http://dx.doi.org/10.1016/j.egypro.2015.01.012 The article is reprinted with kind permission from Elsevier, sciencedirect.com
Paper 4: Edvardsen, Svein; Dorao, Carlos Alberto; Sundsbø, Per Arne. Sudden expansion and two-phase flow pattern transition in pressure recovery zone
Paper 5: Edvardsen, Svein; Dorao, Carlos Alberto; Nydal, Ole Jørgen. Experimental and numerical study of two-phase pressure drop in downhole shut-in valve with Unified Comprehensive Model formulation. Journal of Natural Gas Science and Engineering 2015 ;Volum 23. s. 440-449 http://dx.doi.org/10.1016/j.jngse.2015.02.024 The article is reprinted with kind permission from Elsevier, sciencedirect.com
Utgiver
NTNUSerie
Doctoral thesis at NTNU;;2015:91