The objectives of this project were to develop new computational techniques for the accurate modeling and optimization of advanced wells.

Program
This project was selected in response to DOE's Oil Exploration and Production Mega PRDA Breakout solicitation, DE-RA26-98BC15200-3.

Stanford University
Stanford, CA

Reservoir simulation represents an essential tool for the management of oil and gas reservoirs. A key aspect of reservoir simulation is the representation of the well in the simulator and the linkage of the well to the reservoir. These issues are particularly important in the modeling of advanced or non-conventional wells. Accurate tools for modeling and optimizing advanced wells are needed, as the costs associated with these wells are very high. However, previous modeling techniques were often inadequate.

Project Results
A key aspect of petroleum reservoir simulation is the representation of the well in the simulator and the linkage of the well to the reservoir. This is particularly challenging in the case of advanced wells, which include horizontal, highly deviated, multilateral and "smart" wells. In this project we developed a wide variety of new techniques for the modeling of advanced wells and for optimizing their performance. A new general purpose research simulator was also developed.

Benefits
Our research targeted the development of an improved overall reservoir simulation capability. This can be used to optimize the production of oil and gas from subsurface reservoirs. In the course of this work we developed a general purpose object-oriented research simulator (GPRS) as well as a new software tool (AdWell) for the efficient semi analytical modeling of advanced wells. 

Our work also addressed several other aspects of the modeling of advanced wells. These include the development of techniques for unstructured reservoir simulation, permeability upscaling in the near-well region, and wellbore flow models for multiphase wellbore flow. We also developed procedures for optimizing advanced well deployment and operation. These techniques can be used to maximize the recovery of oil and gas.

Project Summary

• Developed a general purpose research simulator (GPRS) and an efficient semi analytical tool for modeling advanced wells (AdWell)
• Introduced new techniques for efficiently capturing the effects of near-well permeability heterogeneity in flow simulations
• Implemented an optimized drift-flux model for multiphase flow in wellbores
• Developed and applied techniques for optimizing advanced well placement and type and for optimizing smart well performance

This project addressed three key areas: (1) the development of reservoir simulation techniques for modeling advanced wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and for coupling the well to the simulator (which includes the accurate calculation of well index and the modeling of multiphase flow in the wellbore); and (3) accurate approaches to account for the effects of reservoir heterogeneity and for the optimization of advanced well deployment. We achieved substantial progress in each of these areas over the course of this project.

(June 2005)
We continue our activities in many of the areas addressed in this project. Specifically, we are actively developing our general purpose simulation and well modeling capabilities. We are also devising and implementing efficient approaches for smart well optimization. In addition, we are addressing the optimization of advanced well placement under geological uncertainty.

Publications
About 30 papers (journal articles and conference proceedings) were written on this (and closely related) work. The work is summarized in five DOE reports:

Durlofsky, L.J., Aziz, K.: "Advanced techniques for reservoir simulation and modeling of nonconventional wells," Final Report to U.S. Department of Energy, contract no. DE-AC26-99BC15213 (2004) 213 pp.

Durlofsky, L.J., Aziz, K.: "Advanced techniques for reservoir simulation and modeling of nonconventional wells," Annual Report to U.S. Department of Energy (Year 4), contract no. DE-AC26-99BC15213 (2003) 200 pp.

Durlofsky, L.J., Aziz, K.: "Advanced techniques for reservoir simulation and modeling of nonconventional wells," Annual Report to U.S. Department of Energy (Year 3), contract no. DE-AC26-99BC15213 (2002) 139 pp.

Durlofsky, L.J., Aziz, K.: "Advanced techniques for reservoir simulation and modeling of nonconventional wells," Annual Report to U.S. Department of Energy (Year 2), contract no. DE-AC26-99BC15213 (2001) 141 pp.

Durlofsky, L.J., Aziz, K.: "Advanced techniques for reservoir simulation and modeling of nonconventional wells," Annual Report to U.S. Department of Energy (Year 1), contract no. DE-AC26-99BC15213 (2000) 140 pp.

$1,612,484

$626,606 (28% of total)

NETL - Jerry Casteel 
NETL - Deann Rhea (drhea@netl.doe.gov or 918-699-2003) 
Stanford U. - Louis Durlofsky (lou@stanford.edu or 650-723-4142)