oa Reservoir geology of Upper Burgan and prediction of water encroachments: Raudhatain field, northern Kuwait

The presented study involved the integration of logging, coring, sedimentological and dynamic data to build a geological model of the Upper Burgan Reservoir and to predict future water encroachment in it. The Upper Burgan reservoir is the upper part of clastic Burgan Formation, which is the most prolific producer in northern Kuwait. The producing sands were deposited in a deltaic to shoreface environments. Open-hole logs and core data were used to identify and calibrate the quality and type of sands and shales. Correlation of the layers was carried across the field with 20 key wells. A structural map was prepared using a seismic depth of the top Upper Burgan, which was tied to these wells. Isopach maps were prepared using correlation picks. Using cut-offs in gamma-ray logs, the sand reservoirs were picked and mapped for each layer. Conventional electrical logs were used to pick the oil-water contact. Timelapse pulsed neutron logs were used to map the water encroachment. The major sand bodies were deposited as<br>NE-trending channel sands, as consistent with the direction of sediment transport. The quality of the reservoir of the sand bodies improves towards the southwest. The direction of water encroachment is predominantly along the channels. Due to better reservoir quality and proximity to the source, the southwestern part shows a more rapid advancement of the water than the northeastern part. The shoreface sands are relatively poorer quality reservoir and are predominant in the lower part of the Upper Burgan. Due to the low production from these sands, no significant water encroachment was predicted. Deposition in channels in the Upper Burgan controls the flow behavior and is demonstrated to be an important aspect for predicting the future water encroachment in the reservoir.