Turkey, Laila (KOC) | Hafez, Karam Mohamed (KOC) | Vigier, Louise (Beicip) | Chimmalgi, Vishvanath Shivappa (Kuwait Oil Company) | Dashti, Hameeda Hussain (Kuwait Oil Company) | Datta, Kalyanbrata (KOC) | Knight, Roger (KOC) | Lefebvre, Christian (Beicip-Franlab) | Bond, Deryck John (Kuwait Oil Company) | Al-qattan, Abrar (KOC) | Al-Jadi, Manayer (Kuwait Oil Company) | De Medeiros, Maitre (Beicip) | Al-Kandari, Ibrahim (Kuwait Oil Company)
A pilot water flood was carried out in the Marrat reservoir in the Magwa Field. The main aim of this pilot was to allow an assessment of the ability to sustain injection, better understand reservoir characteristics. A sector model was built to help with this task.
An evaluation of the injectivity in Magwa Marrat reservoir was performed with particular attention to studying how injectivity varied as injected water quality was changed. This was done using modified Hall Plots, injection logs, flow logs and time lapse temperature logs.
Data acquisition during the course of the pilot was used to better understand reservoir heterogeneity. This included the acquisition of pressure transient and interference data, multiple production and injection logs, temperature logging, monitoring production water chemistry, the use of tracers and a re-evaluation of the log and core data to better understand to role of fractures.
A geological model using detailed reservoir characterization and a 3D discrete fracture network model was constructed. Fracture corridors were derived from fractured lineaments interpreted from different seismic attribute maps:
A sector model of the pilot flood area was then derived and used to integrate the results of the surveillance data. The main output is to develop an understanding of the natural fracture system occurring in the different units of the Marrat reservoir and to characterize their organization and distribution. The lessons learned from this sector modeling work will then be integrated in the Marrat full field study.
The work described here shows how pilot water flood results can be used to reduce risk related to both injectivity and to reservoir heterogeneity in the secondary development of a major reservoir.
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 obtaininformation in the areas of:
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 astable 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.
The Greater Burgan field is located in the South-Eastern part of Kuwait as shown below and is producing most of the oil for the state of Kuwait. The Burgan reservoir mainly consists of three reservoir units namely Wara, Third, and Fourth sand. The Third and Fourth sand members have excellent reservoir characteristics and are prolific producers. At this time the Third sand is the major producer and contributing around 60-70% of the total present production of the Greater Burgan field.