Lessons Learned From the First Water Flood Pilot Project in a Clastic Reservoir in the Greater Burgan Field in Kuwait

摘要

Greater Burgan in Kuwait is the second largest field and the largest clastic reservoir in the world. Discovered in 1938, the production initially came from Wara sandstone and soon followed by other underlying Burgan clastic reservoirs. Burgan reservoir mainly consists of three reservoir units namely Wara, Third, and Fourth sand. The Wara Water Flood Pilot Project is the first clastic waterflood pilot in Kuwait. Reservoir pressure in Wara has been falling below the bubble-point in many parts of the reservoir. This would ultimately result in free gas evolving from the oil and significant loss in reserve recovery. This pilot was designed with the objective to obtain information in the areas of: 1. Long-Term Injectivity 2. Reservoir Connectivity 3. Water Breakthrough Time and Direction 4. Water-Cut Development 5. Productivity 6. Operational Experience The Wara pilot pattern is of inverted seven spot with one injector, six producers, and one water source and was designed to inject 5,000 to 10,000 bwpd into a single injector and to produce from six producers drilled around the injector. Each well is 250 meters apart and the producers are equipped with ESPs to produce even after water breakthrough. The project has been in the operational phase for the last two years and the main objectives of evaluating long-term injectivity and the reservoir response to water injection in the Wara reservoir were achieved. Results from this pilot were needed to reduce subsurface uncertainty and to support the design of future Wara waterflood projects. This will ultimately help in the decision of whether to build a permanent water flood project to maintain a stable reservoir pressure in the Wara reservoir. This paper highlights the challenges and accomplishments in designing, completing, and operating of this successful water flood pilot project which could benefit other similar projects around the world.