The objectives of the research were to develop a new set of ultra-fast reservoir simulation tools for the prediction of interactions of phase behavior of complex oil and gas mixtures with flow in heterogeneous reservoirs.

Program
This project was selected in response to DOE's Oil Exploration and Production solicitation DE-PS26-01NT41048 (focus area: Gas Flooding). The goal was to improve understanding of three-phase flow and demonstrate improved methods to predict the performance of gas injection processes in heterogeneous reservoirs.

Stanford University
Stanford, CA

High-pressure gas can displace oil and gas relatively efficiently in subsurface formations if displacement conditions are selected appropriately. The project's fundamental objective was to understand the physical mechanisms that control displacement performance in gas injection processes and to use that understanding to develop efficient and accurate computational tools for prediction of project performance at field scale.

Project Results
A three-dimensional (3-D), streamline-based compositional simulator was developed. It allows assessment of the performance of gas displacement processes using numerical or analytical solutions for multi-component displacement along a streamline in combination with high-resolution representation of heterogeneities in the calculation of streamline locations. The resulting predictions of process performance are more accurate than conventional finite-difference compositional simulations and can be obtained in a fraction of the computation time. There is still much work to be done to make compositional streamline methods a fully functional reservoir simulation tool.

Benefits
The computational technique developed allows accurate analysis of gas injection processes at field scale. Conventional compositional simulation is too slow to allow such analysis at field scale; hence the results of this project make possible detailed process performance predictions that could not be done before.

Project Summary
The project entailed four main lines of research: 1) efficient compositional streamline methods for 3-D flow, 2) analytical methods for one-dimensional displacements, 3) physics of multiphase flow, and 4) limitations of streamline methods.

In the first area, results were reported that show how the streamline simulation approach can be applied to simulation of gas injection processes that include significant effects of transfer of components between phases. In the second area, the one-dimensional theory of multicomponent gas injection processes was extended to include the effects of volume change as components change phase and an automatic solution algorithm was developed. 

In the third area an extensive experimental investigation of three-phase flow was performed. The experimental results demonstrate the impact on displacement performance of the low interfacial tensions between the gas and oil phases that can arise in multi-contact miscible or near-miscible displacement processes. In the fourth area, the limitations of the streamline approach were explored.

The results establish that it is possible to use the compositional streamline approach in many reservoir settings to predict performance of gas injection processes. When that approach can be used, it requires substantially less (often by orders of magnitude) computation time than does conventional finite-difference compositional simulation.

(October 2005)
The results of this project are being applied in current research to investigate storage of carbon dioxide emissions in aquifers and coal beds. Building on the expertise gained in this project, project performers now are designing a high-performance industrial compositional streamline simulator (CSLS). The development of a CSLS is being supported by a new DOE cooperative agreement (NT15530).

Publications
Final Report - ""High-Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs"" [PDF-9.08MB], Prepared for the U.S Department of Energy Under Grant No. DE-FC26-00BC15319. Principal Investigator: Franklin M. Orr Jr., Department of Petroleum Engineering, Stanford University.

Jessen, K., Kovscek, A, and Orr, F.M. Jr., "Increasing CO2 Storage in Oil Recovery," Energy Conversion and Management, 46, (2005), pp. 293-311.

Jessen, K., and Orr, F.M. Jr., "Gas Cycling and the Development of Miscibility in Condensate Reservoirs," SPE Reservoir Evaluation & Engineering, 7(5), pp. 334-341, (2004).

Jessen, K., Stenby, E.H. and Orr, F.M. Jr., "Interplay of Phase Behavior and Numerical Dispersion in Finite Difference Compositional Simulation," SPE Journal, 9(2), pp. 193-201, (2004). 

Jessen, K., and Orr, F.M. Jr., "Gravity Segregation and Compositional Streamline Simulation," SPE 89448, Presented at the 2004 SPE/DOE Fourteenth Symposium on Improved Oil Recovery, Tulsa, OK, April 17-21, 2004. (accepted for SPE Journal).

Cinar, Y, Jessen, K., Berenblyum, R., Juanes, R., and Orr, F.M Jr., "An Experimental and Numerical Investigation of Cross-Flow Effects in Two-Phase Displacements," SPE 90568, Presented at the Society of Petroleum Engineers' Annual Technical Conference & Exhibition (SPE ATCE), Houston, TX, October 2004. (Submitted for publication).

Cinar Y., Marquez S., and Orr, F.M. Jr., "Effect of IFT Variation and Wettability on Three-Phase Relative Permeability," SPE 90572, SPE ATCE, September 26-29, Houston, TX, 2004.

Cinar Y. And Orr, F.M. Jr., "Measurement of Three-Phase Relative Permeability with IFT Variation," SPE 89419, SPE REE, (February 2005, pp. 33-43.

Mallison, B., Gerritsen, M., Jessen, K. and Orr, F.M. Jr, "High Order Upwind Schemes for Two-Phase, Multicomponent Flow," SPE 79691, presented at the SPE Reservoir Simulation Symposium, Houston, TX, February 3-5, 2003 (accepted for SPE Journal).

Seto, C.J, Jessen, K., and Orr, F.M. Jr., "Compositional Streamline Simulation of Field-Scale Condensate Vaporization by Gas Injection," SPE 79690, SPE Reservoir Simulation Symposium, Houston, TX, February 3-5, 2003. 

Jessen, K., and Orr, F.M. Jr., "Compositional Streamline Simulation," SPE 77379, SPE ATCE, San Antonio, TX, September 29-October 2, 2002.

Jessen, K., Wang, Y., Ermakov, P., Zhu, J., and Orr, F.M., Jr., "Fast, Approximate Solutions for 1-D Multicomponent Gas Injection Problems," SPE Journal, 6(4), (2001).

Berenblyum, R.A., Shapiro, A.A., Jessen, K., Stenby, E.H., and Orr, F.M. Jr.:,"Black Oil Streamline Simulator with Capillary Effects", SPE 84037, SPE ATCE, October 5-8, 2003, Denver, CO.

$1,107,062

$276,765 (20% of total)

NETL - Sue Mehlhoff (sue.mehlhoff@netl.doe.gov or 918-699-2044)
Stanford U. - Franklin Orr (fmorr@stanford.edu or 650-725-6270)