Differences of fracture characteristics and the influence on productivity in the northeastern Sichuan continental basin

Reservoirs in the northeastern Sichuan continental basin are all tight reservoirs. However, fracture cha-racteristics and their influence on productivity are different among various areas and formations. Comparisons were made based on core, thin section, logging, gas testing and producing data collected from the eastern Yuanba, western Yuanba and Malubei blocks. The eastern and western Yuanba blocks mainly developed shearing fractures with low angle and low density. Fractures in the eastern Yuanba block are more effective than those in the western Yuanba block. The Malubei block developed both shearing and extensive fractures of mechanical geneses, with high angle, density and permeability. The angle, effectiveness and density of macro fractures controlled the productivity of gas wells. A dense micro fracture network or micro fracture dissolution improves the reservoir matrix and determined if a gas well had a stable production.