Assessing Method for the Rocks Wettability by Comparing X-ray Tomograms of a Dry and Contrast Solution Saturate Salvage of Core
S. Galkin, Yu. Kolychev and S. Cherepanov
Event name: GeoBaikal 2018
Session: Poster Session
Publication date: 11 August 2018
Info: Extended abstract, PDF ( 398.8Kb )
Price: € 20
The possibility of direct evaluation of the rocks wettability by X-ray tomography method. The method is based on the comparison of the tomograms in the dry and saturated state, which allows you to visually assess the degree of impregnation of the core. As the saturating agent, an aqueous solution of NaI was used, the addition of which in water does not change the filtration properties of the fluid, increasing its X-ray density. For hydrophilic samples, complete impregnation of the samples is established, for hydrophobic samples there is no impregnation in the central part. As a result, the types of rocks are distinguished by the degree of wettability: hydrophilic, with average signs of hydrophobicity, with strong hydrophobicity characteristics, absolutely hydrophobic. For the samples studied, the reliability of the wettability determinations by the Tulbovich method is established, which overestimates the hydrophobicity of the rocks. To monitor the results of tomography, a microscopic analysis of the sections was performed, showing an increased content of organic matter for hydrophobic samples. In the studied core collection, the results of the wettability evaluation by tomography are in good agreement with the well electrometry data. Samples with an absolutely hydrophobic cut type are characterized by lateral logging resistances of more than 1000 Ohm ∙ m. Samples with signs of hydrophobicity are encountered in intervals with resistances in the range from 120 to 800 Ohm ∙ m. For hydrophilic samples, much lower resistances of less than 100 Ohm∙ m are characteristic. The relationship between wettability and the conductivity of rocks is of great practical importance, since, when confirmed on a larger volume, the core in the long term allows, by the method of lateral logging, to establish the zonality of the types of rock wetability.