US EPA

4961246 

Journal Article 

Oil-Charging Pore-Throat Radius Threshold of Tight Reservoirs: A Comparison on Multi-Method Calculation Results 

Feng, X; Zeng, J; Tao, S; Yang, J; Feng, Sen; Pang, Z 

2017 

Yes 

Journal of Nanoscience and Nanotechnology
ISSN: 1533-4880
EISSN: 1533-4899 

17 

9 

6067-6076 

10.1166/jnn.2017.14414 

WOS:000408354100010 

Accurate calculation on oil- charging pore-throat radius threshold (R-oc) is very fundamental to tight oil exploration and development. Previous studies overlook the pervasive low-velocity non-Darcy flow in the tight reservoirs, which leads to a high pore-entry pressure for oil to charge. This work calculates Roc of the Jurassic tight reservoirs in Sichuan basin, China, by using the following methods: mercury injection capillary pressure (MICP), nuclear magnetic resonance centrifugation (NMRC), and oilcharging (oil displacing water) simulation experiments (OCSE). The results show that R-oc calculated by MICP, NMRC and OCSE are in the range of 0.005-0.04 mu m, 0.093-1.172 mu m and 0.035-0.627 mu m, respectively. Based on our analyses, MICP measurement results in a smaller value of R-oc than the real value because it neglects the water film thickness and the much larger hydrocarbon molecule diameters. The NMRC result is larger since the water film volume in the effective pores is added to the total bound water volume. The OCSE result is reasonable since it takes low-velocity non-Darcy flow into account, which better fits the real situation in the tight reservoirs. 

Tight Reservoir; Oil Charging; Pore-Throat Radius Threshold; Low-Velocity Non-Darcy Flow; Micro-Nano Scale