APPLICATION OF A LOCAL GRID REFINEMENT PROTOCOL TO ANALYZE THE PERFORMANCE OF RESERVOIR SYSTEMS WITH COMPLEX WELL ARCHITECTURES

Open Access
Author:
Hu, Li-Wei
Graduate Program:
Petroleum and Natural Gas Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
December 05, 2011
Committee Members:
  • Turgay Ertekin, Thesis Advisor
Keywords:
  • reservoir simulation
  • complex well structure
  • local grid refinement
Abstract:
Complex architecture multi-lateral wells are relatively new applications in oil and gas field developments because they increase the productivity, reduce the cost of the development, and decrease the footprint and ultimately leading to increased profitability of unconventional oil/gas field projects. In addition to conventional multi-lateral wells, multi-lateral wells with a complex structure can be constructed with not only horizontal branches but also slanted and/or undulating branches, allowing a single well to maximize the productivity by reaching the reservoir layers that conventional multi-lateral wells are unable to reach. In this thesis, a three dimensional, single-phase compressible fluid simulator is presented to model performance of a vertical well, a horizontal well, and multi-lateral wells with complex structures with the flow regimes of these hydrocarbon reservoirs. As an alternative approach to Peaceman’s well equation, wells in the reservoir are approximated by a collection of fine rectangular cells in the locally refined areas, and the residual equation is utilized to calculate the flow from reservoir blocks into well cells. The approach is significantly different from conventional applications using Peaceman’s well equations which are limited by the structure or the path of wells. Combining our reservoir approximation using fine rectangular cells with the local grid refinement technique, we obtain precise production forecasts and capture accurate pressure distributions around the wells. To validate this approach, the developed simulator is used for modeling the productivity of a vertical well and a horizontal well in a single-phase compressible fluid reservoir. These results are compared with predictions from a commercial simulator . A slanted well simulation is also performed and compared with predictions from the commercial simulator. The validation tests show that the approach presented is capable of providing accurate production predictions without the well structure limitation and with shorter simulation times as demanded by the application of a full fine grid refinement method.