A Successful Story: Improving Success Ratio up to 80% of Well Reactivation Job. Pamusian Field Case Study, Tarakan, North Kalimantan, Indonesia

Abstract

Pamusian Field is located in the northern part of North Kalimantan, Zona 10, Pertamina Hulu Indonesia area, approximately 1 km Southeast from center of Tarakan City. Pamusian field is one of the top ten Fields (Kalimantan Area under Pertamina EP operation Area) based on its OOIP, 553 MMSTB with more than 1200 wells drilled since 1905 (brown field). However, this role doesn’t mean Pamusian production stands at a tremendous number of productions. Moreover, only 50 active wells contribute to Pamusian oil production. More than 1000 wells are idle even though there are bunch of oil opportunities on the idle wells. As an overall, Pamusian oil production remained constant for around 500 BOPD at 3 years back before massive reactivation delivered in 2021.

At the end of 2020, aligned with the company’s goal to maximize existing Assets, the idea of production optimization was commissioned by improving the success ratio of well reactivation job in Pamusian Field. In the last 3 years, the success ratio of well reactivation jobs was not encouraging. The team focused on all aspects of optimization and reactivation practices. Field Review and Reactivation Lookback are aggressively conducted to figure out Pamusian Field problems. Lack of workover and well intervention jobs, inadequate surveillance data, and a misperception of well reactivation methods are raised as the root causes for underdeveloped fields. Another surprising fact is more than a hundred attic wells located up dip in the main closure are not active (idle), which has lower surrounding well in a good oil production performance (10-30 BOPD) BOPD with various of water cut 90%. Again, this is real opportunity! low hanging fruit to become more oil by producing those wells.

An integrated and comprehensive assessment was successfully delivered. The most important outcome of this assessment is reactivation method recommendation, it’s called Locomotive (Low Cost, Massive Impact, & Innovative).

Three innovations were created and delivered to conduct well reactivation jobs in the Pamusian field, there are Subsurface Data Hierarchy Development (to set subsurface confident level), Fill up Annulus Activity (to check fluid sample), and Locomotive Risk Mapping Assessment (to set priority by comparing confident & impact level) as a decision tool. These reactivation methods deliver a high confidence level of success. Resulting a dramatic rise of success ratio up to 80% (previously 30% at 3 years back) and oil gain average 150 – 200 BOPD which remained stable for several months until early 2022.