- 责任者：Cao Qing (School of Earth Sciences and Engineering ; Xi’an Petroleum University ; Xi’an 710065 ; China) ; Zhao Jingzhou
- 刊名：Acta Petrolei Sinica
- 出版年：2013
- 卷期：34(6)
- 关键词：致密砂层 ; tight sands ; 砂岩储集层 ; sandstone reservoirs ; 鄂尔多斯盆地 ; Ordos Basin
- 页码：p.1040-1048
- 图表：7 illus., 6 tables, 42 refs.
- 分类号：1003
- issnNo：ISSN0253-2697
- isbnNo：CN11-2128/TE
To determinate physical properly limits of natural gas accumulation in Upper Paleozoic tight sand reservoirs in the eastern Ordos Basin, natural gas stress condition was analyzed in micro pore throat, and irreducible water film, buoyancy, capillary resist- ance and abnormal high pressure and hydropower were considered for the effect of natural gas accumulation. Taking the thickness of irreducible water film as the minimum pore throat radius of tight reservoirs, it could be calculated irreducible water film and deter- mined the lower limit of pore throat radius is equal to 10 nm based on the irreducible water saturation which measured by NMR. The maximum pore throat radius was calculated by critical pore throat radius according to equilibrium state of buoyancy and capillary re- sistance. To determine gas column height of main gas reservoirs at different geologic epoch, the upper limit of pore throat radius was calculated by critical pore throat radius. According to the results of mercury injection experiment, a matching tendency of the median pore throat radius and physical parameters could be established, and petrophysical limit parameters could be calculated based on gen erating the upper and lower limits into the tendency. The calculation results of petrophysical limits were： For the Member 8 of Low er Shihezi Formation, lower petrophysical limits of reservoir are 4% and 0. 1 mD （porosity and permeability）, upper petrophysical limits are 13% and 1.8mD at the end of Early Cretaceous, and 14% and 2.0mD at present; For 3rd sub Member of the Member 2 of Shanxi Formation, the corresponding values are, in order, 2% and 0.01 mD, 8% and 1.0mD, 9% and 1.4reD,For Taiyuan For mation, these are, in order, 3.5% and 0.02mD, 11% and 1.1 mD, 12% and 2.0mD.