Publications

The Senoro Field located in onshore East Sulawesi Arm has proven the presence of prolific petroleum system and the challenges of drilling in active-collision margin. The analysis results from well-centric and field-scale geomechanical analyses in the Senoro Field have revealed several distinctive mechanical stratigraphy characteristics in the Banggai foreland basin. The effect of compressional tectonic regime manifested and coalesce within the basin-fill stratigraphy and anomalous subsurface stresses perturbation. The challenge of drilling in such setting requires integrated geomechanics analysis to identify drilling hazards improve well design and optimize drilling cost. The assessment of geomechanical risk and operational guidance for future drilling campaign is crucial to identify and prevent aggravated drilling issues experienced by the previous high-angle development wells. 1D Wellbore Stability Analysis (WBS) workflow conducted to resolve the vertical stress and pore pressure elastic rock properties horizontal stresses around the wellbore. Fault stability analysis (FSA) conducted to understand the possibility of fault reactivation due to drilling activity. Image log data was also utilized in order to observe the influence of horizontal stresses orientation and magnitude. The assessment shows critical section of the well design lies in the 5000 ft long 12-1/4” intermediate hole across the Kintom Formation overburden zone as the upper part shows low strength due to predominated by shaly-sand lithology with loose grain nature. Furthermore well-centric geomechanical analysis from several wells shows gradual severity of drilling issues correlates with increasing well inclination and high collapse pressure in the shallow overburden section is caused by anomalous stress perturbation. Based on regional 2D seismic dataset thin-skinned thrust-fault zone and major strike-slip zone can be observed in vicinity of the South Senoro Field may explain such higher stress perturbation in the shallow overburden section. Interestingly within the lower part of Kintom Formation overburden and the Carbonate reservoir section normal stress regime prevails and normal fault features predominates. Such change in the stress regime also anticipated as potentially limits the critical mudweight window due to fault reactivation risk. Geomechanical analysis in oil & gas deep wells located in Banggai Basin brings new insight toward subsurface stress condition in active tectonic margin and exemplifies the importance of vertical variation of rock mechanical stratigraphy and subsurface stress perturbation to mitigate drilling hazard. Anomalous stress perturbation in the shallow overburden section highlights the present-day far-field stresses influenced by thin-skinned thrusting detached from the normal-stress deeper reservoir zone.