Utilizing LET Function to Investigate the Capillary Pressure Curves for an Iranian Carbonate Reservoir Rock

Document Type : Research Paper

Authors

1 Enhanced Oil Recovery Research Center, NIOC, Tehran

2 Enhanced Oil Recovery Research Center, NIOC, Tehran, Iran

Abstract

There are several methods to study the capillary behavior of multi-phase flow performance within reservoir rock. One is the actual determination of multiphase flow properties from measured data, and the other is the representation of the proposed functions for capillary pressure. It is essential that these functions have sufficient degrees of freedom to model the measured data. In this study, the new analytical correlation (LET function, proposed by Lomeland and Ebeltoft) is first defined and used to investigate the results of experimental capillary pressure by centrifuge for numerous samples from an Iran carbonate reservoir rock of southern oil fields. Then, by tuning the existing parameters in the function, a model was developed and completed to predict the capillary pressure curves. The results show that without any time and cost used for the experimental measurements of capillary pressure and only by applying the routine core parameters, the developed model can estimate the capillary pressure curves. This developed model is very simple to use and more accurate than other models. In order to demonstrate the validity of this correlation, the predicted results are compared with those obtained from several experimental measurements conducting a centrifuge method on several core samples from one of the Iran carbonated rocks . Regarding the amount of the calculated error (R2<0.18), this method has acceptable accuracy and is easy to use.
 

Keywords


[1]. Bentsen R. G. and Anlie J., “Using parameter estimation techniques to convert centrifuge data into a capillary pressure curve”, Trans., AIME, 56, 1977.
[2]. Brooks R. H. and Corey A. T., “Hydraulic properties of porous media”, Hydraulic, pp. No. 3, Colorado State U., 1964.
[3]. Burdine N. T., “Relative permeability calculations from pore size distribution”, Trans., AIME, 198, pp. 71-78, 1953.
[4]. Jing X. D., and Wunnik J. N. M. van, A capillary pressure function for interpretation of core-scale displacement experiments, SCA 9807.
[5]. Skjæveland S. M., Siqveland L. M., Kjosavik A., Hammervold Thomas W. L. and Virnovsky G. A., “Capillary pressure correlation for mixed-wet reservoirs”, SPE 60900 / SPE 39497 India oil and Gas Conference and Exhibition, New Dehli, India, 17-19 Feb, 1998 / SPE 60900 SPE Reservoir Eval. & Eng. 3 (1), Feb 2000.
[6]. Masalmeh S. K., Abu Shiekah I. and Jing X. D., “Improved characterization and modeling of capillary transition zones in carbonate reservoirs”, SPE Reservoir Evaluation & Engineering, Vol. 10 (2): 191-204 April, SPE paper 109094, 2007.
[7]. Masalmeh S. K., and Jing X. D., Capillary pressure characteristics of carbonate reservoirs: relationship between drainage and imbibition curves, SCA 2006-16.
[8]. Lomeland F., Ebeltoft E. and Hammervold Thomas W., A new versatile capillary pressure correlation, SCA 2008-08.
[9] Aziz K., and Settari A., Petroleum Reservoir Simulation, Applied Science Publishers, 1983, p30.
[10]. Hassler G. L. and Brunner, E., Measurement of capillary pressure in small core samples, Trans, AIME , Vol. 160, 114, 1945.