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Experiment Investigation of Electrical Resistivity Response Characteristics for Gas-bearing Shale
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
Electrical logs is a key method for oil and gas evaluation. Electrical transport property of the rock reflects the pore structure. Electrical resistivity response of gas-bearing shale is complicated because of the complex pore structure. We measured resistivity for gas-bearing shale samples at the relatively low frequency range under condition of dry, full water saturated and desaturated. Simultaneously experimental measurements of TOC, pore structure and mineral composition were made to helpfully analyze the resistivity response. The results show that the resistivity of shale is high and changes largely. The resistivity is mainly from the clay bond water under the dry condition, but resistivity is weak correlated with clay content. Low pyrite content has less contribution to the resistivity response. Although nanoscale pore in the organic matter is dominated, the resistivity decreases rapidly after full water saturated, which shows that pore structure has obvious impact on resistivity response. The resistivity increases after desaturated. The porosity difference between the full water saturated porosity and the desaturated porosity demonstrates ratio of the movable water. Resistivity difference between dry and desaturated reflects the contributions of the clay bond water and the capillary bond water. The resistivity of shale also has clear dispersion.