Perpustakaan Digital ITB

Accurate prediction on formation fracture pressure gradient is one of the most important things to have on planning phase for a drilling program. Unless fracture pressure prediction is considered, troublesome problems will occur when fracture on the formation are developed as the drilling activity goes on. Problem like loss circulation could be extremely noxious for drilling activity that often led to well blowout. Such disasters could have been avoided if a good fracture pressure gradient prediction had been applied on the well planning phase. Several commonly used methods are available to predict fracture pressure. However, the effect of water depth on overburden stress variable, which is often neglected when land-based correlation for offshore areas is used was found to be quite significant [1]. Since the uppermost interval of the Offshore field is water, which considerably less dense than rock, the overburden stress is less then onshore environment [2]. Therefore, the overburden stress variable needs some modification to adjust water depth effect so it can be applied on Offshore environment. Poisson’s ratio also become important factor to make accurate prediction for fracture pressure gradient. Well log data analysis is used to estimate the value of Poisson’s ratio. Leak of Test (LOT) data is also used to validate fracture pressure gradient model. This study provides comparison result of fracture pressure gradient using Eaton Correlation when applicated on onshore and offshore field by using different overburden stress value. This study can be used as guidance for Offshore fracture pressure gradient prediction to provide a clear mud weight-window for specified field’s drilling program. such analysis could also provide an opportunity to deepen the hole segment to create a safer, more stable, and more economical drilling environment [3]. furthermore, this study provides a recommendation to use a specified variables value for different field that will be used in fracture pressure prediction equation.