A manufacturing method of rock samples with specific porosity and permeability for large-scale 3-D physical simulations

Abstract

Making an artificial rock sample with specific porosity and permeability at a low cost to restore heterogeneous characteristics of target formation is significant to improving quality in large-scale 3-D physical simulations. To achieve this goal, the effects of effective stress of compaction (ESC), mass fraction of cements (MFC) and average diameter of grain (ADG) on porosity and permeability of rock samples are primarily analyzed by making 80 artificial core plugs using pressing synthesis technique. The results show that both ESC and MFC are negatively correlated with porosity and permeability. Meanwhile, if rock grains are enough homogeneous in size, only permeability is affected by ADG dramatically and the impact of ADG on porosity is not obvious. Based on the above achievements, two empirical models on the relationships between manufacturing parameters and porosity, manufacturing parameters and permeability are developed respectively, and then they are used to design a sub-meter scale rock sample and calculate its manufacturing parameters. Lastly, this rock sample is used to demonstrate the reliability of method by testing actual porosity and permeability. The validation indicates that absolute error between designing and actual porosity is 2.50% and absolute error of permeability is 20.30%. Manufacturing errors are lower than that of previous works. Additionally, production cost of rock samples is also very low and the total cost of the above sample is about 6000 CN Yuan (900 US Dollars). Thus, this method is reliable and it has great developing potential in large-scale 3-D physical simulations on fluid flow in porous media.