Study Of Permeability Of Shaly Sandstones From Well Logs

Permeability is one of the key reservoir parameters in oil fields, which has been given most attention and effort by petroleum engineers and well logging experts as the important question for discussion both in board and overseas. And the shaly sandstone is the primary type of hydrocarbon reservoirs now. So it is the completely necessary and very significative task to study permeability of shaly sandstone reservoirs.The thesis includes two parts basically, and one model was established in each part for studying permeability of shaly sandstones.In the first part, it was discussed that the effect of different distribution of shale in shaly sandstones on their permeability based on capillary buddle model. And the rudiments of hydrodynamics theory were applied to discuss the problem.The quantitative permeability equations were established for dispersed shale and laminar shale fraction respectively. Beginning with the two equations, a new equation was advanced considering dispersed shale as well as laminar shale. The parameters needed in the model can be acquired from core analysis and well logging data directly or indirectly. Then the model was applied in the Daqing oil field. The good results show that it is viable to apply the model to estimate permeability in oil fields.In the second part, permeability of reservoir sandstones was investigated by using fractal theory, which is one of powerful tools for dealing with complicated, anomalous phenomena and processes. Using this theory fractal pore space geometry of rocks was discussed. At the same time the methods were given to determine the fractal dimension of pore space. It was proven to be feasible that pore fractal dimension can be used to quantitatively study the complexity of pore space geometry of sandstone reservoir. Then the Kozeny-Carmon equation was developed. The new developed fractal model adjusts the measure of the effective pore radius and of the grain radius to the resolution length appropriate for the hydraulic process. The fractal model was applied in the Daqing oil field. Permeability calculated with the model compares very well with permeability measured on core samples. The precision for estimating permeability is high, so the fractal model developed for permeability is valid and feasible.