Abstract: The technology of sidetrack horizontal drilling is a new type of oilfield development technology. But the :key that can make a good beneft or not is dependent on preferred well locations. Based on its special properties and recent technological levels together within the geologic features, remaining oil distribution and present production status of conglomerate oilfelds, the authors proposed preferred principles for the pilot test area, target area or zone and base well locations of sidetrack horizontal drilling. Application of them to Baikouquan oilfeld showed that following implementation of preferred selected well locations, outstanding production effectiveness has been achieved, providing a set of practical and effective techniques of prefered selection of sidetrack horizontal well locations in aging oilfield.

Key words: Baikouquan oilfield, Conglomerate reservoir, Sidetracking, Horizontal well, Well location, Selection