10,370
edits
Changes
Jump to navigation
Jump to search
Line 17:
Line 17: − Discrepancies often exist between laboratory determined porosity values and porosities derived from downhole logs. Some of these discrepancies result from differences inherent in comparing direct measurements of physical properties made on small samples with indirect assessments of averaged properties. Many of these discrepancies, however, can be explained by noting differences in the definition and assessment of porosity (Figure 1).+ − [[file:porosity_fig1.png|thumb|{{figure number|1}}Schematic of a pore system relating mineralogy, water content, and porosity assessment. (Notes: *lf sample is completely disaggregated during measurement. “Varies as a function of height above the free water level.) (After <ref name=pt05r33>Chatzis, I., Morrow, N. R., Lim, H. T., 1983, Magnitude and detailed structure of residual oil saturation: Society Petroleum Engineers Journal, v. 23, p. 311–326., 10., 2118/10681-PA</ref>; modified from Hill et al., 1969.)]]+
→Definition of porosity terms
==Definition of porosity terms==
==Definition of porosity terms==
[[file:porosity_fig1.png|left|thumb|{{figure number|1}}Schematic of a pore system relating mineralogy, water content, and porosity assessment. (Notes: *lf sample is completely disaggregated during measurement. “Varies as a function of height above the free water level.) (After <ref name=pt05r33>Chatzis, I., Morrow, N. R., Lim, H. T., 1983, Magnitude and detailed structure of residual oil saturation: Society Petroleum Engineers Journal, v. 23, p. 311–326., 10., 2118/10681-PA</ref>; modified from Hill et al., 1969.)]]
Discrepancies often exist between laboratory determined porosity values and porosities derived from downhole logs. Some of these discrepancies result from differences inherent in comparing direct measurements of physical properties made on small samples with indirect assessments of averaged properties. Many of these discrepancies, however, can be explained by noting differences in the definition and assessment of porosity ([[:file:porosity_fig1.png|Figure 1]]).
===Total porosity===
===Total porosity===