Abstract: The unique feature of complex small fault block oil reservoir is complex geological structure,complex fluid property and complex oilwater system and so on.By analyzing and researching the relationship between the angles of horizontal well and vertical well,permeability,net thickness,the length of horizontal hole section,oil/water viscosity ratio,vertical well completion section and injector and producer distance,development methods of two kind of horizontal well pattern are researched and reasonable pattern is determined.The result indicates that,with the increase of permeability and the length of horizontal hole section,the decrease of oil/water viscosity ratio,the degree of reserve recovery continuously raises.The influence of effective thickness on the degree of reserve recovery is not severe.And horizontal well and vertical well pattern can exert the double advantage of horizontal wells and vertical wells more fully and enhance oil recovery greatly.

Key words: complex small fault block reservoir, horizontal well pattern, horizontal well and vertical well, injector and producer distance, development effectiveness