Title: Prediction of three-phase saturation profiles from two-phase capillary pressure curves as a function of wettability

Authors: Mohammad Mirzaei; David A. DiCarlo

Addresses: The University of Texas at Austin, 1 University Station, Austin, TX 78712, USA. ' The University of Texas at Austin, 1 University Station, Austin, TX 78712, USA

Abstract: Gravity drainage of oil with gas is an efficient recovery method in strongly water-wet reservoirs and yields very low residual oil saturations. However, many of the oil-producing reservoirs are not strongly water-wet. Thus, predicting the profiles and ultimate recovery for mixed and oil-wet media is essential to design and optimisation of improved recovery methods based on three-phase gravity drainage. In this study, we perform two- and three-phase gravity drainage experiments in sand-packed columns with varying wettability. We propose a simple method for predicting the three-phase equilibrium saturation profiles as a function of wettability. In each case, the three-phase results were compared to the predictions from two-phase results of the same wettability. We find that the gas/oil and oil/water transition levels can be predicted from pressure continuity arguments and the two-phase data. The predictions of three-phase saturations work well for the water-wet media, but become progressively worse with increasing oil-wet fraction. [Received: April 12, 2011; Accepted: September 19, 2011]

Keywords: three-phase saturation profiles; gravity drainage; capillary pressure; wettability; oil-wet; fractional-wet; oil reservoirs; petroleum reservoirs; gas-oil; oil-water; recovery methods.

DOI: 10.1504/IJOGCT.2012.046317

International Journal of Oil, Gas and Coal Technology, 2012 Vol.5 No.2/3, pp.123 - 141

Available online: 03 Apr 2012 *

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