Maximising Oil Recovery in Mature Water Floods Using Automated Pattern Flood Management

Abstract

One of the most significant challenges for extending production life in mature waterflood fields is high water production. Couple with high reservoir heterogeneity, extensive layering and faulting, these fields often developed irregular flood patterns after decades of production which compounded the challenge to optimizing recovery from these fields. The severity of this problem can be seen in the Niger Delta oil fields where there are several matured fields that are producing at high water cut after many years of water flooding. The main objective of this study is to maximize oil recovery from a matured waterflood oil field while reducing the water cut. To achieve this objective, simulation studies were conducted on two cases scenarios. The first case was modelling and running waterflood simulation studied without applying pattern flood management (No PFM) while the second case scenario was done by exploring an automated pattern flood management (PFM). This was done with the aid of Petrel E&P software platform and ECLIPSE FrontSim to efficiently optimize the rate of water allocated to individual injectors. Using data from one of the oil fields operating in the Niger Delta, their performances were compared. The PFM gave the best result with a cumulative oil production of 30,727,470 STB when compared with the case of No PFM which gave a cumulative oil production of 26,968,224 STB (about 12% increase in oil recovery). The PFM water cut was 16% when compared with the case of No PFM which gave a water cut of 47% (about 63% reduction in water production). Hence, The PFM approach has made it possible to reduce water injection in more than 30% of the injectors while more than 62% of the producers experienced increase production and reduced water cut. The productivity increased upon automation of the workflow will enable engineers to identify the optimal injection allocation factors. It will also help engineers to understand and produce from the reservoir at an optimized decline rate and ensure the increase in ultimate recovery.