Study and application of connecting relationship during water injection of well groups in carbonate reservoirs, Tahe oil field

In the initial attempt of water injection in carbonate fractured-vuggy reservoirs in the Tahe oil field, only a few wells were effective, and the relationship between water injection and production was unclear. Based on the systematic analyses of production dynamic variety during different stages of water injection wells and oil producing wells, three methods, including unit differential pressure curve, energy nodal analysis, and high-pressure water injection to balance well group energy, were summarized to establish well group link and make clear well relationship. Unit differential pressure curve deals with the well group which injecting in multiple wells and producing in a single well, and can determine the connective response among wells. Energy nodal analysis focuses on the changing points on energy indicating curves of oil wells, and shows the relationship between injection and production among wells. For those well groups with differential pressure and were not effective during water injection, we use high-pressure injection to balance energy and establish well group link. With these methods, we determined well relationship and dynamic response, established injection and production well group, guided the production of well group, promoted water injection development level, and enhanced Tahe oilfield reserves production.