Abstract: It is difficult to determine the parameters such as net pay thickness and permeability of fractured-vuggy carbonate reservoirs using conventional methods. This paper presents a combination method for determination of them: Based on the production and performance data, the formation factor is firstly calculated by the methods of production index and well-testing interpretation. Then the relationship between the water breakthrough time and the open/perforating thickness, net pay thickness and other related parameters is established. Following determination of the net pay thickness by trial and error method, the reservoir permeability is finally determined, which is equal to formation factor divided by net pay thickness. This combination method has been applied to the fractured-vuggy carbonate reservoirs in Tahe oil field, showing that the calculate results are reasonable and reliable, and this method is more practicable.

Key words: fractured-vuggy reservoir, net pay thickness, permeability, method