Characteristic of Permeability and Porosity of a 2D High-Permeable Model with Etched Network Channels

Abstract

Waterflooding is the most common development method for oil field. However, long-term water injection could result in the formation of high-permeable zone in reservoir. The high-permeable zone would reduce water sweeping efficiency, making water injection ineffective. The accurate understanding of the high-permeable may contribute to the selection of effective and efficient governing methods, which could enhance oil recovery further. The characteristic of permeability and porosity is the crucial parameter to describe high-permeable zone. A customized macroscopic two-dimensional etched network channel model (Khezrnejad et al. Nanofluid enhanced oil recovery–mobility ratio, surface chemistry, or both?, In: International symposium of the Society of Core Analysts, St. John’s Newfoundland and Labrador, Canada, 2015, pp 16–21, [1]) was used to simulate the high-permeable zone by long-term water flooding in the research (Han et al. in Multiscale pore structure characterization by combining image analysis and mercury porosimetry, In: SPE Europec/EAGE annual conference and exhibition, Society of Petroleum Engineers, 2006 [2]). Because of the small pressure difference in the model, the constant head method was conducted to measure the permeability. Meanwhile, the capacity of permeation water was measured by falling head method, with the coefficient of permeability obtained. Tiab and Donaldson (Petrophysics: theory and practice of measuring reservoir rock and fluid transport properties, Gulf professional publishing, Houston, Texas, 2015, [3]) To simulate the primitive formation condition, the kerosene was saturated with the model and the porosity was calculated after the pore fulfilled. The experimental results showed that the macroscopic model could represent the condition of high-permeable zone after waterflooding. The measurement of permeability and coefficient of permeability was feasible. Comparing the two different methods derived from Darcy`s equation which characterized the permeable and discussing the experimental results in details, the constant head method to characterize the permeability was more accurate. The result of porosity measurement indicated that the use of kerosene was more representative with precise porosity of two-dimensional etched network channel model.