A Fully Integrated Method for Dynamic Rock Type Characterization Development in One of Iranian Off-Shore Oil Reservoir

Document Type : Original Paper

Authors

Research Institute of Petroleum Industry, Tehran, Iran

Abstract

Rock selection in modeling and simulation studies is usually based on two techniques; routinely defined rock types and those defined by special core analysis (SCAL). The challenge in utilizing these two techniques is that they are frequently assumed to be the same, but in practice, static rock-types (routinely defined) are not always representative of dynamic rock-types (SCAL defined) in the real reservoir. There is also no significant link between these two techniques. To fill this gap, we integrate the well log data for identification of the optimal number of rock-types, and SCAL data with its high interpretive potential in a given reservoir zonation.
In this paper, we propose a method in one of Iranian offshore oil reservoir with a tight carbonate formation for dynamic rock type characterization. In this method, with the integration of well logs and core description data using multivariate statistical methods, different static rock-types can be identified, but these rock types cannot be assigned for fluid flow simulation. So, with our approach based on capillary pressure curves, different flow behavior can be classified. This technique can be done by using integration of similar capillary pressure curves due to the inlet pressure corresponding to the log parameters.
Finally, with integration of capillary pressure and well log data, two different dynamic rock-types with distinct flow behavior were identified. This method can be used for the development of rock-type characterization and deriving of saturation height functions for calculation of initial water saturation in any heterogonous reservoir and it is an applicable solution for inputs in Geomodel and also simulation models.

Keywords


[1] Shin-Ju, Ye and Rabiller, P. June (2000). “A new Tool for Electro-facies Analysis: Multi-Resolution Graph-based Clustering.” SPWLA 41nd Annual Logging Symposium, 4-7.
[2] Shin-Ju, Ye and Rabiller, P. June (2001). “The Iterative Use of clustering and modeling to improve permeability prediction.” SPWLA 42nd Annual Logging Symposium, 16-20.
[3] Hammon, G. Oct. (2003). “Two-Phase Flow Rock-Typing: Another Perspective.” SPE paper 84035 presented at the SPE Annual Technical Conference and Exhibition held in Denver, Colorado, U.S.A., 5-8.
[4] Granier, B. (2003). “A new approach in rock-typing, documented by a case study of layer cake reservoirs in field “A”, offshore Abu Dhabi (U.A.E).” Notebooks on geology, maintenon, Article 2003/0.
[5] Garcia Pereira, H. (1990). “Improving reservoir description by using geostatistical and multivariate data analysis techniques.” Mathematical Geology.
[6] Heon Lee, S., Kharghoria, A. and Datta-Gupta, A., June (2002).“Electrofacies Characterization and Permeability Predictions in Complex Reservoirs.” Paper SPE 78662,
SPE Reservoir Evaluation & Engineering.
[7] Silva, F.P.T., Ghani, A., Al Mansouri, A. and Bahar, A. Oct. (2002). “Rock Type Constrained 3D Reservoir Characterization and Modelling.” SPE 78504, 10th ADIPEC,
Abu Dhabi, 13-16.
[8] Martin, A. J., Solomon, S. T. and Hartmann, D. J. (1997). “Characterization of Petrophysical Flow Units in Carbonate Reservoirs.” Paper Published in The American Association of Petroleum Geologists.
[9] Ahmad, T. (2000). Data Reservoir Engineering, Handbook, ISBN 0-88415-770-9. 10- G. Anderson, W. (1990). “Improving Wettability Literature Survey_Part 5: The Effects of Wettability on Relative Permeability.” Mathematical Geology.
[11] Ghedan, Sh. G., Thibot, B. M. and Boyd, D. A. Oct. (2001). “Modeling and validation of Initial Water Saturation in the Transition Zone of Carbonate Oil Reservoirs.” SPE Paper 88756 presented at 11th Abu Dhabi international petroleum Exhibition and conference held in Adu Dhabi, U.A.E., 10-13.
[12] Worthington, P. F. and Gaffney Oct. (2000).“Scale Effects on the Application of Saturation-height functions to Reservoir Petrofacies Units.” SPE paper 73173 presented at the SPE Annual Technical Exhibition and conference, Dallas, 1-4.
[13] Masalmeh, S.K. Oct. (2002). “The Effect of Wettability on saturation Functions and Impact on carbonate reservoirs in the Middle East.” SPE paper 78515 presented at 10th Abu Dhabi international petroleum Exhibition and conference, 13-16.
[14] Archer, J.S. and Wall, C.G. (1986). “Petroleum Engineering: principles and practice.” Imperial College of Science and Technology, London, 92-115.
[15] Hammon, G.Oct. (2000). “Field-Wide Variations of Wettability.” SPE paper 63144 presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, U.S.A., 1-4.
[16] Aminian, K., Ameri, S., Oyerokun, A. and Thomas, B. May (2003). “Prediction of Flow Units and Permeability Using artificial Neural Networks.” SPE paper 83586 presented at the SPE Western Regional/AAPG Pacific Section Joint Meeting held in Long Beach, California, U.S.A., 19-24.
[17] Engtrom, F. and Toft, J.C. (2005). Experience Using EQR Modeling for saturation Predictions in a Middle East Carbonate Reservoir, IPTC 10878.
[18] Engtrom, F. (1955). “A new method to normalize capillary pressure curves.” SCA conference paper number 9535, 1955.