Abstract:

This article researches the reservoir's horizontal stress field uniform trends in the later half period of water flood on theory, based on the problems facing in developing the extremely low permeability reservoirs with fractures. The authors come  to  the conclusion that the regional minimum apparent horizontal principal stress at the stage of later half period will be close to the horizontal maximum principal stress as the cycle extending of water flooding.The injecting water flow laws of the extremely low permeability reservoirs with and without fractures are described in the paper. Water injection adjustment of the extremely low permeability reservoir is put forward according to the theory of uniform on horizontal stress field. The adjustment has been tested in Mao 11 well  district in Toutai Oilfield in Daqing, which has a good benefit and will have guidance to the same kind of oil field.

Key words: extremely low permeability reservoir with fracture, change of ground stress field, development policy in later half period, Toutai Oilfield in Daqing