The oil reservoirs in Block-T of Yanchang Oilfield have the characteristics of low temperature and low permeability. Most of injection wells and oil wells have been fractured repeatedly

and the effect of water injection development is poor because of the water breakthrough along fracture or dominant channels. In order to solve the problems existing in the water flooding development of Block-T

combined with the advantages of air foam flooding

its field test was carried out in 2007 to explore its feasibility in low temperature and low permeability reservoirs and certain effects had been obtained. Based on the effects of the preliminary tests

its site application scale expanded after 2011. After years of field tests

the air foam flooding shows good effects in the low temperature and low permeability reservoirs now

and the complete supporting technology and safety guarantee measures have been formed. The field test shows that the measures applied in about 70 % of the single wells are effective

the average oil production per month of single well increases by 2.2 t

the comprehensive water cut reduces by 25 %

and the oil recovery improves by 1.21 %. The air foam flooding has a good effect in low temperature and low permeability reservoirs of Yanchang Oilfield.