AN INTEGRATED HYDRODYNAMIC / PVT VERTICAL WELLBORE MODEL FOR TWO-PHASE NATURAL GAS / LIQUID SYSTEMS

Open Access
Author:
Sadegh, Abdallah Ahmed
Graduate Program:
Petroleum and Natural Gas Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
May 15, 2006
Committee Members:
  • Michael Adebola Adewumi, Committee Chair
  • Turgay Ertekin, Committee Member
  • Robert W Watson, Committee Member
  • Mku Thaddeus Ityokumbul, Committee Member
  • Mark Stephen Klima, Committee Member
Keywords:
  • Natural gas
  • Condensate
  • wells
  • Multiphase flow
  • Wellbore model
Abstract:
Multiphase flow in the wellbore poses a challenge for production engineers since characterization of prevailing flow regime determines the appropriate pressure drop calculation method. The problem is further complicated when the flowing fluid undergoes phase changes. The key objective was to develop a wellbore flow model based on sound physical principles, incorporating state of the art hydrodynamic and thermodynamic tools. The model developed comprises a flow pattern detection routine, hydrodynamic model, and an equation-of-state-based phase behavior package. The model was extensively tested with 30 field cases, proving to accurately predict pressure drop for single and two-phase (gas/condensate) flow giving an average absolute error of 6.3%. The inherent challenges were handling phase changes as pressure, temperature and/or composition vary. Accurate prediction of fluid properties was also crucial. The model provides a convenient tool for the production engineer for well design and can be readily incorporated in NODAL analysis.