New Drilling Insights from Well-Centric Geomechanical Analyses in Active-Collision Margin, Banggai Basin, Indonesia

Abstract

Abstract The challenge of drilling in relatively frontier area with active collision margin typical of Eastern Indonesian foreland basins requires an integrated geomechanics analysis to identify drilling hazards, improve well design, and optimize drilling cost. Earlier batch drilling located in the northern part of the Senoro Field targeting on pinnacle carbonates did not encounter significant drilling issue, except for minor tight spots and losses in the carbonate reservoir section. However, later drilling batch in the southern part of the field which associated with large strike-slip faulted platform carbonates encountered significant drilling issues related with pack-off, tight hole, and stuck pipes while tripping in 5000 ft long 12-¼” hole section within the Kintom Formation overburden, despite of initial high penetration rate. In order to identify and prevent similar drilling issues, 1D Wellbore Stability Analysis (WBS) workflow conducted to solve 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. In addition, lessons-learned from drilling experience and best-practice improvement in offset well is also evaluated to validate with the geomechanics analysis results. Introduction The uniqueness and importance of K-shaped Sulawesi island is long recognized as one of the most tectonically active area in the world where plate collision occurred and has been major interest for research in fields of academic and E&P industry. Recent oil and gas discoveries and multiple potential exploration play in the East Sulawesi area has resulted several prominent mid- to large-sized gas condensate fields, which prompted exploration and development drilling activities since the early 2000’s (Barmi, 2003; Hasanusi, 2004). This trend shows the development of oil and gas field will be increasingly important operation in the area (Fig.1 location map)