| PDF: | |
| Time: | 2022 |
| Journal: | world geology |
| Pages: | |
| Type: | Other |
| Author: | HAN Xu,HUANG Yulong,LIU Xingzhou,GUO Qiang |
Abstract: | Based on coring and conventional logging data of 16 wells，lava flow units of Paleogene basalts in Liaohe depression are divided into four layers including massive layer ( Φv ＜ 1%，Φe ＜ 5%) ，minor vesicular layer ( 1% ＜ Φv ＜ 5%，5% ＜ Φe ＜ 10%) ，medium vesicular layer ( 5% ＜ Φv ＜ 10%，10% ＜ Φe ＜ 15%) and highly vesicular layer ( Φv ＞ 10%，Φe ＞ 15%) through core description，thin section identification，scanning electron microscope，porosity ( Φe) measurement and vesicle proportion ( Φv) statistics． It is proposed that the lower limit of AC in minor vesicular layer ( 59. 7 μs·ft － 1 ) ，lower limit of AC in medium vesicular layer ( 61. 5 μs·ft － 1 ) and the upper limit of AC in medium vesicular layer ( 84. 3 μs·ft － 1 ) as the logging division of massive，minor vesicular， medium vesicular and highly vesicular layer，respectively． Three types of reservoir distribution patterns and their logging responses are summarized including tabular lava flow unit，vesicular-massive and minor-highly vesicular interbedding compound lava flow unit． The effective porosities of basaltic reservoir are composed of residual infilling vesicles，amygdaloid dissolved porosities and micropores inside amygdaloid of clay minerals． On the whole，high-quality reservoirs are primarily developed in the minor-highly vesicular interbedding lava flow unit due to larger vesicle proportion． |