Calculation of saturation in carbonate reservoirs based on electrical efficiency
Li Xiong-Yan1, Qin Rui-Bao1, Liu Chun-Cheng1, and Mao Zhi-Qiang2
1. CNOOC Research Institute, Beijing 100027, China.
2. College of Geophysics and Information Engineering, China University of Petroleum, Beijing 102249, China.
Abstract：
We derived an equation for saturation in carbonate reservoirs based on the electrical efficiency model in the case of lacking core data. Owing to the complex pore structure and strong heterogeneity in carbonate reservoirs, the relation between electrical efficiency and water porosity is either complex or linear. We proposed an electrical efficiency equation that accounts for the relation between electrical efficiency and water porosity. We also proposed a power-law relation between electrical efficiency and deep-formation resistivity and analyzed the factors controlling the error in the water saturation computations. We concluded that the calculation accuracy of the electrical efficiency is critical to the application of the saturation equation. The saturation equation was applied to the carbonate reservoirs of three wells in Iraq and Indonesia. For relative rock electrical efficiency error below 0.1, the water saturation absolute error is also below 0.1. Therefore, we infer that the proposed saturation equation generally satisfies the evaluation criteria for carbonate reservoirs.
LI Xiong-Yan,QIN Rui-Bao,LIU Chun-Cheng et al. Calculation of saturation in carbonate reservoirs based on electrical efficiency[J]. APPLIED GEOPHYSICS, 2014, 11(2): 215-222.
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2014, Vol. 11 
