Publications

The Bunyu structure in the Bunyu field is a marginal field that was discovered by BPM (Bataafsche Petroleum Maatschappij) in 1901 and produced since 1922. Since 1995 the structure of Bunyu has been managed by Pertamina until now. The cumulative Bunyu field production has reached 109.99 MMSTB oil and 330.81 BSCF gas. In 2010 the Y-18 well, which was one of the wells in the Bunyu structure, produced up to 6,100 bopd. This triggered the Bunyu structure to become a backbone for Pertamina EP production in Asset 5 region with reservoir characteristics deposited in a deltaic environment. The rate of natural decline of seventy percent production per layer becomes a major challenge in maintaining and increasing production in this field. Several factors that cause the failure to achieve production include: reservoir pressure down on existing production wells, drilling results in the Bunyu structure that have not yet reached the target, and the high low and off production due to the increase in water content, sand problem, and conditions of the production facilities that need refurbishment. The depleted pressure is the nature of the reservoir in Bunyu where the dimensions of the reservoir are small and lack connectivity. On the other hand, the achievement of the success of the Bunyu wells drilled from 2014 to 2015 was only 17.4%. To address these challenges, one of the Bunyu field production improvement strategies was carried out with a revolution in the selection of drilling well candidates that was originally done in a structural concept. Through the Sectorization-Gridbase-Stepout (SGS) method, candidates have gone through a comprehensive evaluation process from play concept into stratigraphic concept in the stepout area. The comprehensive evaluation includes building static model then dynamic data approach, generating sectorization map with gridbase plan. In August 2017, Pertamina drilled two wells (X-174 and Y-50) in the new fault block based on SGS method. This well proved to be a success and confirmed the new play in outstep concept. It shows hydrocarbon potential in deep zones. It produced 1200 bopd and 0.6 mmscfd of gas. The rest of the zones are still to be tested. The SGS Method had proven the stratigraphic play in Bunyu even in an anticline flank. It has contributed significantly to Asset 5 production and Pertamina EP target achievement.