Abstract: In Tarim oilfield, there exist a great number of sand bottom-water reservoirs, where the output accounts for a large proportion of the total amount. At present most bottom-water reservoirs are experiencing significant bottom water coning, rapid increase of water-cut, serious production decline and great difficulty in maintaining the stablilized prodction. Therefore it is of vital to know accurately the water coning behavior. This paper made an in-depth study on some problems of reservoir performances which are researchers concerned most, such as: calculation of water coning scale,calculation of water-flooded volume of bottom- water reservoirs and calculation of volumetric sweep efficiency of the bottom-water reservoir etc. We also provided a practical calculation method for field application. Calculation made for a certain Tarim oilfield demonstrated that the results calculated in this way are reasonable and reliable,the method used is correct, and can accurately represent the practical performances of the oilfield.

Key words: bottom-water reservoir, water coning, performance, sweep efficiency, high water cut stage