Clastic strata porosity evolution model analysis in sedimentary basins
Shi Hui1, Liu Zhen1, Pan Gaofeng1, Hu Xiaodan2
1. National Key Laboratory for Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249;
2. Geophysical Technique Research Centre, Bureau of Geophysical Prospecting, China National Petroleum Corporation, Zhuozhou, Hebei 072751
It is direction from qualitative analysis to quantitative research for studying clastic strata porosity evolution,kowning well which during geologic process could help to deepen knowledge about hydrocarbon accumulation mechanism.This paper has researched Member 8 sandstones,yanchang Formation in Zhenting area and Member 7 mudstones,Yanchang Formation in Jiyuan area,and has established mathematical models respectively for sandstone and mudstone porosity evolution,with current porosity characteristics as entry point and geologic time as principal line,combining with research of burial and diagenetic history.Sandstone porosity evolution can be divided to total porosity-decreasing in that mainly mechanical compaction and cementation result and regional porosity-increasing in that mainly dissolution result.So having separately established porosity evolution models of decreasing effect and increasing effect,sandstone porosity evolution model is their addition.Exactly mudstone porosity evolution is the composition of porosity-decreasing mathematical model during normal compaction and porosity-increasing mathematical model during undercompaction.