Abstract: For a well producing from reservoir with bottom water and gas cap, the water and gas avoidances must be taken into consideration for its position of optimum perforation. The critical flow rate of well decreases with the increase of perforated degree, while the flow rate of well increase with the increase of perforated degree. Base on theoretical analysis, the method for determination of optimum perforated degree of reservoir with bottom water and gas cap is presented. Technically, the optimum perforated degree of well is defined as its critical flow rate is equal to its flow rate. However, the case study shows that under barrier-free condition the perforated degree is used to being lower and resulting in lower flow rate of well. Therefore, the barrier distribution should be taken into consideration for the perforation of reservoir with bottom water and gas cap.

Key words: gas cap, bottom water, well, perforation interval