- 责任者：Zhou Feng (School of Earth Sciences and Engineering ; Nanjing University ; Nanjing 210023 ; China) ; Xu Mingjie
- 刊名：Geological Journal of China Universities
- 出版年：2013
- 卷期：19(4)
- 关键词：孔隙结构 ; pore structure ; 致密砂层 ; tight sands ; 鄂尔多斯盆地 ; Ordos Basin
- 页码：p.588-593
- 图表：4 illus., 3 tables, 16 refs.
- 分类号：1003
- issnNo：ISSN1006-7493
- isbnNo：CN32-1440/P
Core samples from a well in Ordos basin are used to study the elastic properties of tight gas sands in lower Shihezi Formation. Elastic parameters are measured at in-situ physical conditions. The total pore space is divided into three space types based on the microscopic analyses. Soft porosity model （SPM） is modified to construct a new model which could represent the tight gas sands reservoir. A modeling example using the well-log data from Daniudi gas field is completed using seff-consistent theory. Model predicted results include Vp, Vs, Poisson＇ s ratio, acoustic impedance of P wave and acoustic impedance of S wave. Comparison of those elastic properties derived from the model, well-log, and core sample measurement is conducted to evaluate the new model. Predicted Vp, Vs are overall in agreement with well-log data. The same agreement also appears in Poisson＇ s ratio curve. But the model predicts a slightly different behavior of rocks from the core samples in the impedance of P wave （AIp） and acoustic impedance of S wave （AIs）. Predicted AIp and AIs are slightly higher than those of core samples. Pressure may be the main factor responsible for the difference between the model and core samples. The AIp and AIs are calculated from velocity and density, which are derived from the well-log data. The density in-situ condition is higher than what is measured in laboratory because of the pressure produced by upper strata. So the predicted AIp and AIs show a slight rise in comparison to the core samples. This article provides a good example of applying SPM to tight gas sands of Ordos＇ and show that the model will be very helpful to predict elastic properties of tight gas reservoirs.