کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4691903 1636762 2014 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Pore fabric geometry inferred from magnetic and acoustic anisotropies in rocks with various mineralogy, permeability and porosity
ترجمه فارسی عنوان
هندسه پارچه پوسته از انجماد از مغناطیسی و صوتی در سنگ های با کانی شناسی مختلف، نفوذ پذیری و تخلخل
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی


• We present a combined approach to infer the pore orientation in sandstones and carbonates rocks.
• Two methods were used based on ferrofluid impregnation and the measurement of anisotropy of acoustic velocities.
• With the ferrofluid only one part of the porosity is investigated, i.e. the connected porosity, with a size > 10 nm.
• Acoustic velocity deals with a larger range of porosity but is more complicated to interpret.
• Successful of ferrofluid impregnation is driven by methodological considerations.

The ferrofluid impregnation technique combined with anisotropy of magnetic susceptibility measurements (AMSff) is one of the ways to analyze the 3-D geometry of the pore space in a rock and indirectly to infer the anisotropy of permeability. We applied this method on different types of rocks (sandstones and carbonates) with a range of different porosity values (10–30%) and permeability (1 mD to 1 D). To get additional information on both the pore aspect ratio and the directional anisotropy we used another technique, measuring the anisotropy of P-waves velocity (APV) in dry and water saturated conditions. Comparing between both methods shows that despite the good agreement in directional data, inferring the true shape of the porosity is not straightforward. Modeling the presence of an elastic anisotropy in the solid matrix for sandstones allows one to get more consistent values for the pore aspect ratio obtained from both APV and AMSff. However for the carbonate rocks, due to an intricate distribution of microstructures, the aspect ratios obtained show significant discrepancies between the two methods. The ferrofluid method is very sensitive to the quality of the impregnation and suffers from a major drawback which is the threshold size of investigation, limited by the size of the magnetite nanoparticles (10 nm) and probably this method doesn't see all the porosity. On the other hand with acoustic methods, the range of porosity investigated is probably larger but several microstructural attributes can contribute to the elastic anisotropy which makes the pore shape effect more difficult to decipher. Therefore, we promote the combined use of both methods in order to get more reliable information on the pore shape in porous media.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volume 629, 26 August 2014, Pages 109–122
نویسندگان
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