IDLE WELLS PRIORITIZATION USING MULTICRITERIA DECISION-MAKING ANALYSIS

• Main Author: Sudira Wardana, Ragil
• Format: Theses
• Language: Indonesia
• Subjects: Manajemen umum
• Online Access: https://digilib.itb.ac.id/gdl/view/50470
• Institution: Institut Teknologi Bandung

the last five years, the oil industry has been experiencing an oil price downturn. This low oil price condition creates many oil wells to lose its economy to produce oil. Companies can choose to leave those wells in an inactive state and designated them as idle wells. The pitfall is idle well carries the risk of well integrity problems. This problem might cause hydrocarbon leakage to the environment, which can result in adverse economic and environmental impacts. In the last five years, the idle wells in PT SPI have been increasing, with a total of 2467 idle wells in 2019. With the increase of idle wells, the risk of well integrity problems increases subsequently. Driven by the growing environmental concern and its upcoming production sharing contract (PSC) expiration, PT SPI currently focuses on reducing its environmental liability significantly. Supporting that objective, Well Integrity and Abandonment team (WIPA) team, the team who manages well integrity in PT SPI conducts effort to reduce the risk of well integrity incidents on idle wells. Using focus group discussion (FGD) and problem tree analysis, it is concluded that many high-risk idle wells are not yet plugged and abandoned (P&A) increases the risk of well integrity incidents. This condition is caused by the lack of understanding of the risk level on idle wells and the fact that current P&A candidate selection only focuses on wells with severe wellbore problems. Based on this issue, this research combines the analytic hierarchy process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to develop a hybrid multi-criteria decision making (MCDM) model. This model serves as a risk assessment framework to prioritize high-risk idle wells for P&A activity. In the assessment framework, the risk level is evaluated based on the surface condition, subsurface condition, and public exposure factors on each idle well. These factors are expanded further into 13 sub-criteria: wellhead leak, casing/tubing barrier, wellhead condition, tubing hanger, duration idle, well age, top of cement, leak at soil/cellar, HIS on well pad, fence, building distance, building within 150 m and distance to surface water. The result from this research is the risk of well integrity incident on idle wells is expected to be reduced after the mitigation plan is completely executed. The unacceptable risk level will be eliminated by conducting P&A jobs on 247 high risk idle. The As Low As Reasonably Practicable (ALARP) level frequency is expected to be reduced as well. A decision support system (DSS) based on the model is developed to ensure the accessibility and repeatability of the decision-making process. The empirical result from this research can serve as a reference for oil companies in assessing risk levels on idle wells to develop idle wells management plan and mitigate its liabilities.