E3S Web Conf.
Volume 146, 2020The 2019 International Symposium of the Society of Core Analysts (SCA 2019)
|Number of page(s)||11|
|Section||Improved SCAL Techniques and Interpretation|
|Published online||05 February 2020|
Improved method for complete gas-brine imbibition relative permeability curves
1 CSIRO Energy, Australian Resources Research Centre, Kensington, Western Australia 6076
2 Chevron Australia, QV1, 250 St George’s Terrace Perth, Western Australia, 6000
3 Chevron Energy Technology Centre, 3901 Briarpark Drive, Houston, Texas 77042 USA
* Corresponding author: Ben.Clennell@csiro.au
§ Present Address: BHP Petroleum, 125 St George’s Terrace, Perth W.A. 6000.
Standard test methods for measuring imbibition gas-brine relative permeability on reservoir core samples often lead to non-uniform brine saturation. During co-current flow, the brine tends to bank up at the sample inlet and redistributes slowly, even with fractional flow of gas to brine of 400:1 or more. The first reliable Rel Perm point is often only attained after a brine saturation of around Sw=40% is achieved, leaving a data gap between Swirr and this point. The consequent poor definition of the shape of the Rel Perm function can lead to uncertainty in the performance of gas reservoirs undergoing depletion drive with an encroaching aquifer or subjected to a water flood. We have developed new procedures to pre-condition brine saturation outside of the test rig and progress it in small increments to fill in the data gap at low Sw, before continuing with a co-current flood to the gas permeability end-point. The method was applied to series of sandstone samples from gas reservoirs from the NW Shelf of Australia, and a Berea standard. We found that the complete imbibition relative permeability curve is typically ‘S’ shaped or has a rolling over, convex-up shape that is markedly different from the concave-up, Corey Rel Perm curve usually fitted to SCAL test data. This finding may have an economic upside if the reservoir produces gas at a high rate for longer than was originally predicted based on the old Rel Perm curves.
© The Authors, published by EDP Sciences, 2020
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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