This paper is an update to an earlier submission[1] and presents the current status and progress of several main EOR projects in Malaysia.
As of January 2005, the estimated oil-in-place from producing fields in Malaysia stands at about 17.0 Bstb[2], with estimated ultimate recovery (EUR) of 5.62 Bstb. This translates to an averaged recovery factor of only 33.0 percent for producing fields in Malaysia. PETRONAS had realized the importance to further increase the recovery factor and so far has been pursuing EOR implementation in its fields aggressively. To date, a full-field WAG application in Dulang field[3,4] is already at its final stages of implementation. In addition, EOR projects have also been planned for another ten fields i.e. Tabu, Tapis, Guntong, Tiong/Kepong and Angsi in Peninsular Malaysia and Baronia, West Lutong, St. Joseph, Bokor and Baram in East Malaysia.
Each of the project is currently at different level of maturity and some preliminary results for five selected EOR projects that are in the late stages of study or in the pilot phase; namely in Dulang[3,4], Tabu, Baronia, West Lutong5 and Tapis6 fields will be discussed in this paper.
Introduction
Malaysia oil reserves were in declining trend starting from 1994 to 2002 (Figure 1) but reversed its trend with the discoveries of deepwater fields. In 2004, Malaysia's average oil production was about 620 thousand barrels per day. With no new reserves addition, Malaysia would quickly deplete its reserves and at current rate of production, the expected reserves life is only about 19 years.
With responsibility of developing and adding value to these resources, PETRONAS, short for Petroliam Nasional Berhad, was established in 1974, has the responsibility of developing and adding value to these key national resources. The corporation is vested with the entire oil and gas resources in Malaysia and is engaged in a wide range of activities, including upstream exploration and production to downstream of oil refining, petrochemicals, retail business, marketing, trading, gas processing and liquefaction as well as in logistic and maritime.
Through various efforts undertaken by PETRONAS, the reserves have returned to an upward trend, and as at January 2005, the Malaysian oil reserves stood at 4.1 billion barrels2. In a matured exploration and producing area like Malaysia, one of the ways to increase oil recovery is through implementation of EOR projects. In view of this, PETRONAS had conducted a screening study in year 2000 to identify EOR potential in Malaysian oil reservoirs7. The outcome of the study indicated that an estimated un-risked incremental recovery from EOR is about 1 Bstb. It is also interesting to note that the year 2000 study identified CO2 miscible process as potential EOR in 4 out of the top 6 candidate reservoirs (Figure 2).
EOR Initiatives
Recognizing the potential of enhanced oil recovery in the fields, the national oil company endorsed a comprehensive IOR/EOR screening study in year 20007.The main processes studied were chemical, gas flooding and microbial enhanced oil recovery, processes that were considered having the most practical aspects in the Malaysian oil fields.The hydrocarbon and CO2 gas flooding in miscible or immiscible mode were found to be the most favorable processes, although the applications for miscible processes are limited due to depleted reservoir pressures.To further enhance sweep efficiency, mobility control (such as in WAG) and optimizing operating cost for the injectant seems to be the way forward.Most of the proposed gas flooding will be implemented together with water injection in water-alternating-gas (WAG) scheme.
