Choosing the Optimum Water Injection Pattern in Mishrif Formation Nasiriyah Oilfield

Abstract

A process of water injection into Mishrif reservoir in Nasiriyah oilfield south of Iraq was performed in this study depending on 3D reservoir simulation model. The main purpose of this research was to earn the maximum oil recovery and pressure maintenance through increasing reservoir energy by injecting water into Mishrif formation representing the main production reservoir in Nasiriyah oilfield. Depending on fourteen vertical oil wells data, 3D numerical reservoir simulation model has been performed to initiate water injection recovery strategy to increase field production for a long period. Basically the reservoir was modeled employing PETREL&ECLIPSE-100 softwares, where the model boundary was defined according to the geostatistical geological model boundary. Five water injection patterns have been used involving (peripheral, direct line drive, staggered line drive, inverted-5 spot and inverted-9 spot pattern). Subsequently, four of the suggested patterns were combined with peripheral injection wells for the pressure optimization support from reservoir flanks. The estimated initial oil in-place was about 7945 MSTB.The study results elucidate that the optimum injection pattern was inverted 9-spot, with the longest oil production rate (20 year) achieving maximum oil recovery factor (11.04%) and increasing reservoir pressure to be (175.5 bar) till the end of the prediction interval.