Geostress effect on resistivity and its relevant correction method

Abstract

For reservoirs with abnormally high pressure and high geostress, formation resistivity can be greatly affected. This increase of resistivity resulting from high stress causes errors in the identification of reservoir fluids. In order to investigate the effect of stress on resistivity, resistivity measurement was conducted simultaneously with triaxial testing to obtain rock resistivity under high temperature and high pressure. The changes of resistivity and resistivity increasing coefficient with horizontal differential stress and minimum horizontal stress were revealed from experiments. Besides, field data were analyzed to show the main influencing factors of formation resistivity under reservoir conditions. In addition, a new resistivity correction model for high geostress formation was derived in this work. The interpretation results are in good agreement with well testing data in the Keshen area of the Tarim oilfield, China.

Keywords

Resistivity correction / Reservoir fluid identification / Effect of geostress

Acknowledgements

The authors would like to acknowledge China Petroleum logging Co. for providing the logging data used in the study. We also appreciate Qian Wang and Long Yuan for their help in conducting the experiments.

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