Carboniferous volcanic rock reservoirs classification and development practices of Jiu-5 block in Karamay oilfield

Carboniferous reservoirs of Jiu-5 block are part of upper wall of Ke-Bai fractured zone in Junggar basin and belong to fractured volcanic massive reservoirs,with a double low porosity and low permeability.In combination with reservoir microscopic research,the production regularity of single well in carboniferous reservoirs has been analyzed.The results show the carboniferous reservoirs can be mainly classified as the 3 classes and 5 types,class-I fracture type(IF)and crack- matrix type(IFM),class II,crack- matrix type(IIFM)and matrix type(IIM),and class-III,class matrix(IIIM).Each type has an obvious static and dynamic reservoir characteristic.On the plane,from the craterto outward,class-I,class-II and class-III reservoirs are developed.On the section,class-I is mainly distributed on the upper carboniferous,class-II is universally distributed and class-III is on lower carboniferous.According to different reservoir characteristics and distribution regularities of different types,corresponding simulation measures have been made.Through development practice,good development effects and high levels of volcanic reservoirs have been achieved,with the natural decline rate of 20%~50%and ultimate recovery of 16.7%.