Charge Evaluation of South East Abu Dhabi (Part I, Petroleum System Analysis)

Abstract

The Abu Dhabi Company for Onshore Oil Operations (ADCO) is exploring for oil in a contract area in South East Abu Dhabi (SEAD). In order to understand the regional charge variations and to identify the best oil prospects, a large-scale petroleum system analysis was carried out. Results of this study supported portfolio ranking and optimization of the drilling sequence. The petroleum system analysis was carried out following Shell’s workflows for Integrated Charge Evaluation which comprises of three main elements: (1) a source rock evaluation, (2) a regional oil typing exercise and (3) a 3-D basin modelling study. The study was based on ADCO’s and Shell’s regional knowledge, experience and database. The results obtained revealed that the petroleum systems in SEAD are different from the main Tuwaiq Mountain / Hanifa (TM/H) petroleum system in Central Arabia. For instance: the oils recovered from the Hanifa reservoirs in SEAD are different from those in Central Arabia. The absence of the ‘typical’ TM/H hydrocarbon family in SEAD was supported by the source rock screening, which revealed that the Tuwaiq Mountain / Hanifa has little to no source potential in the immediate area. However, several source rock intervals were identified in the Cretaceous Thamama Group, in agreement with an earlier study by Taher (1997). The regional oil typing suggests that the oils present in the SEAD were generated by a separate kitchen area to the North and migrated up-dip in a southerly direction. The source rock maturation and hydrocarbon migration history was modelled in a 3 -D and results are the subject of a separate presentation.