Optimal Field Development of Immature Clastic Heterogeneous Brownfield with Waterdrive: Subba Field, South Iraq Case Study

Abstract

This paper presents an optimization analysis of different development options of Nahr Umr reservoir in Subba oilfield. Nahr Umr reservoir is a highly heterogeneous clastic reservoir with moderate edge a bottom waterdrive and it has a short production history for six months. Many different development scenarios have been conducted in this study to test possible predictive scenarios to determine the most significant development option. The black oil commercial software simulator, Eclipse-100 was used to study fluid flow in the reservoir and to predict the future behavior of reservoir. The prediction scenarios considered in this study include, natural depletion through the existing wells, determine the optimal number of infill producers, and waterflooding option through conducting peripheral and five-spot patterns. The development plan assumed to commence at January 2017, then couple of runs using simulator flow model were conducted for ten years. The waterflood sceneries startedup on January 2023 and January 2027 for inverted five-spot and peripheral patterns respectively with 58 producers and 66 injectors for peripheral pattern and 102 producers and 77 injectors for inverted five-spot pattern. The results are analyzed based on economic criteria to optimize the number of infill drilling. The optimization of development options was achieved based on net present values analysis.

Geological Modeling for Nahr Umr Formation in Subba Oil Field, Southern Iraq

“…Nahr Umr Formation deposited during Early Cretaceous period and it is considered as one of the main reservoirs in the southern of Iraq and neighboring regions (Al-Khazraji and Shuker 2015). The stratigraphic column of the Nahr Umr Formation of an Albian clastic unit characterized by the massive clean basal sands which are overlain by a mixture of silt, shale and massive clean sand interbeds.…”