At Rozet Field, the lack of abundant core analyses or modern logs necessitates the adoption of more assumptions than usual in order to estimate OOIP and remaining recoverable reserves. Two different methods for calculating the recovery efficiency of the waterflood were applied withinnine 5-spot patterns resulting in maximum rates of 40% and 30% respectively. Average recovery factors in the combined 5-spot patterns are 27.5% and 24.4% respectively. Both values indicate the waterflood is probably not as effective as it could have been when compared to similar fields producing from the Muddy Formation.
The USR laterals drilled by Viper Drill improved the performance of both wells in which the method was applied. A significant increase in production in the Signal Hill #14 well and a significant reduction of injection pressure while maintaining steady injection rates in the Signal Hill #16 well strongly indicate (1) that there was near-wellbore damage that was adversely affecting the ability to recovery oil or inject water in the two wells tested and (2) Viper Drill was successful in alleviating the problem.
The Lower Cretaceous Muddy Formation is a significant oil-bearing interval in the Powder River Basin. Most traps in the formation are stratigraphic in nature, with compartmentalized flow units comprising fine-grained to very finegrained sandstones deposited within up to six separate members. Primary production from typical Muddy reservoirs results from a robust solution gas drive with little produced formation water. Some fields, particularly those producing from the lower members deposited in fluvial or estuarine environments, are sensitive to the introduction of foreign water, making waterflooding problematic. Those fields producing from the upper members, deposited in marine environments, tend to react to water-flooding much more favorably.
Wyoming has world-class fields that have proven to be excellent targets for CO2 enhanced oil recovery (CO2 EOR) and have potential to recover significant future oil reserves from Wyoming reservoirs. CO2 EOR has been used in Wyoming since 1986 and there are nine commercial-scale floods that are currently active in the State.
Evaluating the effectiveness of products and/or methods that might improve oil and gas production in Wyoming is one of the functions of the Enhanced Oil Recovery Institute (EORI). As part of that effort, EORI sponsored an evaluation of a novel product that reportedly could help reduce the detrimental effects of paraffin precipitation and deposition in oil wells.
© Enhanced Oil Recovery Institute. All Rights Reserved.
Website Design: Waves Web Design