Publications

Several predictions have previously been published in the IPA conventions using the 6 wells available in the giant Banyu Urip Isolated Carbonate Platform oil field in the East Java basin. After drilling 32 of the 42 development wells, we can now provide an update on the major uncertainties highlighted in those papers - structure, reservoir quality (environments of deposition and diagenesis of the various carbonate zones), lost circulation occurrence during drilling, prediction of cement quality and results and creation of permeability other than the matrix permeability. Two key uncertainties that will be the focus of this paper are reservoir quality and excess permeability features in relation with successful field development and production. In a broad sense, the new wells are mostly confirming the predictions made pre-drill but are refining them. For instance, the wells found transitional facies between tight rind and high quality Platform Interior suggesting a gradational diagenetic process. The new wells have refined the shape of the Drowning Cap and given it sharper edges that enhance the predicted wedding cake build of aerially restricting each successive younger sequence as the platform is drown. Another key challenge in the Banyu Urip development well program was achieving good cement behind pipe in the presence of loss zones so that perforation zones could be closed off from water influx and the well still produced updip. Predictions indicated that encountering total mud losses would be common in this program and sometimes the losses would not be controllable and cement would be poor. The new wells are indicating that losses are occurring dominantly in the sequences as predicted and those loss zones have been as severe as predicted. There has been a concerted effort by the Drilling Team to cure the losses with DOB2C which has been extremely successful in allowing good cement jobs and full log data acquisition.