An Analysis of Development Effects of Pilot in Oil Rim Zone in Gas Cap Reservoir with Low Permeability and Low Porosity in Baozhong Oilfield

Baozhong block in Baolang oilfield with reserves of 5.35m tons is an anticline gas cap reservoir where con-densate gas accumulated in the structural high of the anticline and an oil rim with an area of 5.9km2 developed in the middle. Three pilot test well groups were allocated in the oil rim zone in the center of the structure. Pilot test results showed that daily oil output and water injection were 6.5 tons and 9m3 respectively before stimulation, while incremental daily oil output was 3.0 tons and daily water injection tripled and oil recovery rate was up to 1.24% after acidization. Reponse time of oil wells was 6 monthes when production-injection well spacing was 250m.