An Integrated Workflow of IOR/EOR Assessment in Oil Reservoirs

摘要

This paper presents a comprehensive workflow to screen, rank and evaluate improved and enhanced oil recovery (IOR/EOR) opportunities for given reservoirs. This multidisciplinary workflow was applied to multiple oil reservoirs, aiming to improve volumetric sweep and recover bypassed oil. This comprehensive screening workflow integrates the static and dynamic reservoir conditions, and fully couples with geological and geophysical characterization. Firstly, a parametric screening and ranking for various IOR/EOR techniques for the target reservoirs are performed. Secondly, an advanced EOR screening process incorporating the evaluation of geological framework, facies distribution, flow barrier, reservoir production performance and other key reservoir rock and fluid characteristics is applied. The impacts of critical parameters to production performance are rigorously investigated, including various diagnostic plots of waterflood. The oil reservoirs were pre-screened by oil initially in place (STOIIP) and current production rate to screen out the less attractive reservoirs for EOR. Five top-ranked reservoirs were evaluated by integrating geological characteristics (static) and dynamic reservoir indicators. Diagnostic plots such as water oil ratio (WOR), oil rate, number of active oil producers, GOR, reservoir pressure, water injection and production profdes were analyzed to investigate the reservoir performance. Through this workflow, additional opportunities were identified to increase production and/or extend the reservoir life. The reservoir screening for IOR/EOR assessment revealed a high side opportunity of adding over 5.2 MMBOE of recovery through effective reservoir management. A portfolio of most attractive EOR targets was generated for decision making by higher management. The integrated IOR/EOR screening workflow, evolved from practical field experience, is beneficial for revitalizing mature waterfloods, effective reservoir management, recovering bypassed oil, and more importantly the design and implementation of suitable EOR pilots.