Rejuvenation of Matured Oil Fields in South Sumatra, Indonesia

Abstract

Abstract Pertamina DOH SBS located in South Sumatra, Indonesia, operates the largest area of oil fields under Pertamina own operations. It has 55 fields mostly discovered and developed fifty years (even for some more than a hundred years) ago. The common problems encountered in the old oil fields are lack of data; old facilities; artificial lifts requirement, depleted in pressure and reserves; and high water cut problems. This paper reviews a comprehensive study on rejuvenation of the matured fields in Pertamina DOH SBS by employing a cross function synergy team (multidiscipline team) and project management approaches. The teams consist of geophysicists, geologists, reservoir engineers, operation/ production and facility engineers, and professionals from supporting department such as finance, logistics, HSE, HRD, IT, etc. The project called Production Enhancement Projects (PEP) was established in 2001 and divided into phases. The first phase of PEP that was assessing detailed subsurface and surface facilities data has been done successfully resulting in 45.6 MMBO of additional oil reserves within 12 selected existing matured fields. Besides, the upside potentials are identified as a surprising spill over of the study. Plan of further development for each field has been proposed including the evaluation of economics and environment aspects by considering in-depth GGRP (geophysic-geology-reservor-production) study and intensive discussion among team leaders, team members, and management. After prioritizing the proposed work plan, several implementations of well work (such as: reopening; re-perforating; reparation; sidetracking, twin drilling; etc.) show some successful results. At least two wells will be drilled this year (2002) to prove the upside potentials of oil located in deep zones of the existing fields. Introduction Pertamina DOH SBS has 55 oil and fields extended in two operating areas. Those are East Operation Area and West Operating Area. The West area is located in Pendopo field complex, while the East Area is in Prabumulih field complex. Figure 1 shows the situation map of two areas and its surrounding fields. Based on the field assessment, the total number of fields is 55 consisting of 32 active fields (with 3 fields are relatively new) and 23 non-active fields. The non-active fields are mostly abandoned because of high water cut or depleted. The others are still under observation with limited number of wells. The most active fields have a potential remaining reserve, although those have been produced for tens of years, even for some more than a hundred years. The problems could be identified as follows: there are limited data available either the quantity or its quality; the most production facilities are old with a low efficiency; the reservoirs have been depleted in reserves and pressures; the most active wells have high water cut problems, and some need artificial lifts optimization. These problems affected the performance of success ratio of proposed workovers and development drilling activities, and finally, it does not meet a production forecast. Consequently, the production/operating cost is getting higher. With a spirit of solving these problems, especially for rejuvenating the matured fields, we have been conducting a new plan and strategy of integrated production enhancement projects (it is then called PEP). Accordingly, the knowledge, skills, tools, and techniques are applied on all activities of production optimization (developing and managing the matured fields with its all limitations). The steps of this project are Planning (Re-setting Strategy), Implementing, Monitoring and Evaluating, and Reporting. If the realization is far from the planning, then we do Revising. The detail of these steps will be provided in the next paragraph with a discussion of the problems encountered. History of Oil Fields in South Sumatra The first oil well in South Sumatra, Indonesia, was discovered in 1870, and developed in 1896 by Muara Enim Petroleum Company located in Kampong Minyak Block. In 1902, The Royal Dutch and Shell established Asiatic Petroleum Company that focused on oil transportation and trading. Since 1907, these companies merged with other oil companies established De Bataafshe Petroleum Maatschappij (BPM) to take the exploration-production activities, the Asiatic Petroleum to have a trading business, and the Anglo Saxon to provide the transportation services.