Casabe has been under waterflooding for more than 30 years. The heterogenities of the reservoir and the commigled injection implemented at the beginning of the waterflooding, resulted in early break through times. In 2007, selective injection was implemented allowing to inject separately in each layer and, therefore, to have injection distribution through Injection Logging Tools (ILT). However, producer wells are completed in commigled and with PCP or SRP systems, making difficult access the well to have any information about production distribution. At the current phase of the field development, the production distribution is key information for reservoir management to make decisions about short to medium plans to optimize production.
By pass systems has been used in 9 5/8” casings with enough room to set an ESP and a by pass system (Y-tool). In Casabe field, producer wells are completed with smaller casing diameter representing a real challenge due to the lack of space to accommodate an ESP with a bypass system.
This paper presents the sucessfull application of Slim ESP with by pass system installed in high water cut wells with 7” and 29 #/ft casing, to run conventional production logging tools to determine production distribution and to identify swept and damage zones, PI per layer, crossflow between layers and not producing zones. The challenge of production logging in this environment was not only related to the type of completion in Casabe field (completions with rods and smaller diameter), but also to the multilayer characteristics and high water cut which needed an especific set of tools and sensors to have the best accuracy in the oil and water distribution per layer. A Production Logging Tool of 1-11/16” and a set of 8 probes for bubble counting was a must to achieve the objectives, so the Slim ESP with bypass system was selected based on this condition. After reviewing several combinations, a Slim ESP 319 series and a bypass system with a drift of 2.087” was selected as unique solution. Producction logging has been perform for the first time in Casabe field with a conventional PLT, with no operational problems and with clear results related to oil and water production distribution allowing making short term decisions such as isolating swept zones, stimulating damaged zones or optimizing injection in delpeted zones, but also allowing to understand the real behavoir of the wells and reservoir with the current completion strategy which help to make medium term decisions about reservoir management and field development.