The Gulf of Thailand is characterized by pull-apart rift basins containing extensive en-echelon grabens and half-graben intra-basin fault systems. Both act as the pathway for hydrocarbon upward movement and as the trapping mechanism. The main reservoirs are compartmentalized sands and show rapid lateral stratigraphic changes because of their fluvial nature further segmented by faults. In this geological setting, the highest hydrocarbon pays often lie behind (upthrown side) the fault. To maximize the possibility of encountering trapped hydrocarbons, wells are drilled along and as close as possible to the fault plane. This paper reviews the impact of this complex geological setting on well trajectory characteristics and their planning aspects.
The Gulf of Thailand is also known for its fast drilling rate, which motivated operators to implement a factory drilling approach in their field development programs. The fast track nature of the drilling program requires an unconventional methodology to complete complex well plans in very limited time. The study revealed that strong collaboration between geoscientists and engineers are instrumental to significantly improve the well planning workflow. It further seeks to establish a preferred methodology through the implementation of integrated technology combined with a multidisciplinary collaborative culture. Using this methodology resulted in a significant improvement in terms of planning time and a better choice of trajectories.